1
|
Smith CEL, Laugel-Haushalter V, Hany U, Best S, Taylor RL, Poulter JA, Wortmann SB, Feichtinger RG, Mayr JA, Al Bahlani S, Nikolopoulos G, Rigby A, Black GC, Watson CM, Mansour S, Inglehearn CF, Mighell AJ, Bloch-Zupan A. Biallelic variants in Plexin B2 ( PLXNB2) cause amelogenesis imperfecta, hearing loss and intellectual disability. J Med Genet 2024:jmg-2023-109728. [PMID: 38458752 DOI: 10.1136/jmg-2023-109728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Accepted: 02/22/2024] [Indexed: 03/10/2024]
Abstract
BACKGROUND Plexins are large transmembrane receptors for the semaphorin family of signalling proteins. Semaphorin-plexin signalling controls cellular interactions that are critical during development as well as in adult life stages. Nine plexin genes have been identified in humans, but despite the apparent importance of plexins in development, only biallelic PLXND1 and PLXNA1 variants have so far been associated with Mendelian genetic disease. METHODS Eight individuals from six families presented with a recessively inherited variable clinical condition, with core features of amelogenesis imperfecta (AI) and sensorineural hearing loss (SNHL), with variable intellectual disability. Probands were investigated by exome or genome sequencing. Common variants and those unlikely to affect function were excluded. Variants consistent with autosomal recessive inheritance were prioritised. Variant segregation analysis was performed by Sanger sequencing. RNA expression analysis was conducted in C57Bl6 mice. RESULTS Rare biallelic pathogenic variants in plexin B2 (PLXNB2), a large transmembrane semaphorin receptor protein, were found to segregate with disease in all six families. The variants identified include missense, nonsense, splicing changes and a multiexon deletion. Plxnb2 expression was detected in differentiating ameloblasts. CONCLUSION We identify rare biallelic pathogenic variants in PLXNB2 as a cause of a new autosomal recessive, phenotypically diverse syndrome with AI and SNHL as core features. Intellectual disability, ocular disease, ear developmental abnormalities and lymphoedema were also present in multiple cases. The variable syndromic human phenotype overlaps with that seen in Plxnb2 knockout mice, and, together with the rarity of human PLXNB2 variants, may explain why pathogenic variants in PLXNB2 have not been reported previously.
Collapse
Affiliation(s)
- Claire E L Smith
- Institute of Medical Research, St James's University Hospital, University of Leeds Faculty of Medicine and Health, Leeds, UK
| | - Virginie Laugel-Haushalter
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U1258, CNRS-UMR7104, Université de Strasbourg, Strasbourg, France
| | - Ummey Hany
- Institute of Medical Research, St James's University Hospital, University of Leeds Faculty of Medicine and Health, Leeds, UK
| | - Sunayna Best
- Institute of Medical Research, St James's University Hospital, University of Leeds Faculty of Medicine and Health, Leeds, UK
- Yorkshire Regional Genetics Service, Leeds Teaching Hospitals NHS Trust, Leeds, UK
| | - Rachel L Taylor
- Manchester Centre for Genomic Medicine, St Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, UK
- Division of Evolution and Genomic Sciences, Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, School of Biological Sciences, University of Manchester, Manchester, UK
- EMQN CIC, Manchester, UK
| | - James A Poulter
- Institute of Medical Research, St James's University Hospital, University of Leeds Faculty of Medicine and Health, Leeds, UK
| | - Saskia B Wortmann
- Department of Paediatrics, University Children's Hospital, Salzburger Landesklinken (SALK) and Paracelsus Medical University, Salzburg, Austria
- Amalia Children's Hospital, Radboudumc, Nijmegen, The Netherlands
| | - Rene G Feichtinger
- Department of Paediatrics, University Children's Hospital, Salzburger Landesklinken (SALK) and Paracelsus Medical University, Salzburg, Austria
| | - Johannes A Mayr
- Department of Paediatrics, University Children's Hospital, Salzburger Landesklinken (SALK) and Paracelsus Medical University, Salzburg, Austria
| | - Suhaila Al Bahlani
- Dental & OMFS Clinic, Al Nahdha Hospital, Government of Oman Ministry of Health, Muscat, Oman
| | | | - Alice Rigby
- Institute of Medical Research, St James's University Hospital, University of Leeds Faculty of Medicine and Health, Leeds, UK
- School of Dentistry, University of Leeds Faculty of Medicine and Health, Leeds, UK
| | - Graeme C Black
- Manchester Centre for Genomic Medicine, St Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, UK
- Division of Evolution and Genomic Sciences, Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, School of Biological Sciences, University of Manchester, Manchester, UK
| | - Christopher M Watson
- Institute of Medical Research, St James's University Hospital, University of Leeds Faculty of Medicine and Health, Leeds, UK
- North East and Yorkshire Genomic Laboratory Hub, Central Lab, St James's University Hospital, Leeds Teaching Hospitals NHS Trust, Leeds, UK
| | - Sahar Mansour
- Lymphovascular Research Unit, Molecular and Clinical Sciences Research Institute, St George's Hospital, University of London, London, UK
- SW Thames Regional Centre for Genomics, St George's University Hospitals NHS Foundation Trust, London, UK
| | - Chris F Inglehearn
- Institute of Medical Research, St James's University Hospital, University of Leeds Faculty of Medicine and Health, Leeds, UK
| | - Alan J Mighell
- School of Dentistry, University of Leeds Faculty of Medicine and Health, Leeds, UK
| | - Agnès Bloch-Zupan
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U1258, CNRS-UMR7104, Université de Strasbourg, Strasbourg, France
- Faculté de Chirurgie Dentaire, Université de Strasbourg, Strasbourg, France
- Centre de référence des maladies rares orales et dentaires O-Rares, Filière Santé Maladies rares TETE COU, European Reference Network CRANIO, Pôle de Médecine et Chirurgie Bucco-dentaires, Hôpital Civil, Hôpitaux Universitaires de Strasbourg (HUS), Strasbourg, France
| |
Collapse
|
2
|
Hany U, Watson CM, Liu L, Smith CEL, Harfoush A, Poulter JA, Nikolopoulos G, Balmer R, Brown CJ, Patel A, Simmonds J, Charlton R, Acosta de Camargo MG, Rodd HD, Jafri H, Antanaviciute A, Moffat M, Al-Jawad M, Inglehearn CF, Mighell AJ. Heterozygous COL17A1 variants are a frequent cause of amelogenesis imperfecta. J Med Genet 2024; 61:347-355. [PMID: 37979963 PMCID: PMC10982616 DOI: 10.1136/jmg-2023-109510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 10/17/2023] [Indexed: 11/20/2023]
Abstract
BACKGROUND Collagen XVII is most typically associated with human disease when biallelic COL17A1 variants (>230) cause junctional epidermolysis bullosa (JEB), a rare, genetically heterogeneous, mucocutaneous blistering disease with amelogenesis imperfecta (AI), a developmental enamel defect. Despite recognition that heterozygous carriers in JEB families can have AI, and that heterozygous COL17A1 variants also cause dominant corneal epithelial recurrent erosion dystrophy (ERED), the importance of heterozygous COL17A1 variants causing dominant non-syndromic AI is not widely recognised. METHODS Probands from an AI cohort were screened by single molecule molecular inversion probes or targeted hybridisation capture (both a custom panel and whole exome sequencing) for COL17A1 variants. Patient phenotypes were assessed by clinical examination and analyses of affected teeth. RESULTS Nineteen unrelated probands with isolated AI (no co-segregating features) had 17 heterozygous, potentially pathogenic COL17A1 variants, including missense, premature termination codons, frameshift and splice site variants in both the endo-domains and the ecto-domains of the protein. The AI phenotype was consistent with enamel of near normal thickness and variable focal hypoplasia with surface irregularities including pitting. CONCLUSION These results indicate that COL17A1 variants are a frequent cause of dominantly inherited non-syndromic AI. Comparison of variants implicated in AI and JEB identifies similarities in type and distribution, with five identified in both conditions, one of which may also cause ERED. Increased availability of genetic testing means that more individuals will receive reports of heterozygous COL17A1 variants. We propose that patients with isolated AI or ERED, due to COL17A1 variants, should be considered as potential carriers for JEB and counselled accordingly, reflecting the importance of multidisciplinary care.
Collapse
Affiliation(s)
- Ummey Hany
- Leeds Institute of Medical Research, University of Leeds, St. James's University Hospital, Leeds, UK
| | - Christopher M Watson
- Leeds Institute of Medical Research, University of Leeds, St. James's University Hospital, Leeds, UK
- North East and Yorkshire Genomic Laboratory Hub, Central Lab, St. James's University Hospital, Leeds, UK
| | - Lu Liu
- Leeds Institute of Medical Research, University of Leeds, St. James's University Hospital, Leeds, UK
- School of Dentistry, Clarendon Way, University of Leeds, Leeds, UK
| | - Claire E L Smith
- Leeds Institute of Medical Research, University of Leeds, St. James's University Hospital, Leeds, UK
| | - Asmaa Harfoush
- School of Dentistry, Clarendon Way, University of Leeds, Leeds, UK
| | - James A Poulter
- Leeds Institute of Medical Research, University of Leeds, St. James's University Hospital, Leeds, UK
| | - Georgios Nikolopoulos
- Institute for Fundamental Biomedical Research, B.S.R.C. 'Alexander Fleming', Vari, Attica, Greece
| | - Richard Balmer
- School of Dentistry, Clarendon Way, University of Leeds, Leeds, UK
| | - Catriona J Brown
- Birmingham Dental Hospital, Mill Pool Way, Edgbaston, Birmingham, UK
| | - Anesha Patel
- LCRN West Midlands Core Team, NIHR Clinical Research Network (CRN), Birmingham Research Park (West Wing), Vincent Drive, Edgbaston, Birmingham, UK
| | - Jenny Simmonds
- North East and Yorkshire Genomic Laboratory Hub, Central Lab, St. James's University Hospital, Leeds, UK
| | - Ruth Charlton
- North East and Yorkshire Genomic Laboratory Hub, Central Lab, St. James's University Hospital, Leeds, UK
| | | | - Helen D Rodd
- Academic Unit of Oral Health Dentistry and Society, School of Clinical Dentistry, University of Sheffield, Sheffield, UK
| | - Hussain Jafri
- Fatima Jinnah Medical University, Punjab Thalassaemia and Other Genetic Disorders Prevention and Research Institute, Lahore, Pakistan
| | | | - Michelle Moffat
- Paediatric Dentistry, The Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Maisoon Al-Jawad
- School of Dentistry, Clarendon Way, University of Leeds, Leeds, UK
| | - Chris F Inglehearn
- Leeds Institute of Medical Research, University of Leeds, St. James's University Hospital, Leeds, UK
| | - Alan J Mighell
- School of Dentistry, Clarendon Way, University of Leeds, Leeds, UK
| |
Collapse
|
3
|
Moore RJ, Pretty I, Douglas GVA, Mighell AJ. Review of 1.75 million referrals over 34 months identifies the disruptive impact of the SARS-CoV-2 pandemic on oral surgery care in England: a service evaluation. Br Dent J 2023:10.1038/s41415-023-5526-1. [PMID: 36801960 PMCID: PMC9936481 DOI: 10.1038/s41415-023-5526-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 11/01/2022] [Accepted: 11/08/2022] [Indexed: 02/19/2023]
Abstract
Aims This study aimed to use electronic referral management system (eRMS) oral surgery data across multiple sites in England to evaluate the service over a 34-month period in relation to: 1) pre- and post-pandemic referral rates in oral surgery; 2) examining the data for signs of inequality in obtaining a referral for oral surgery; and 3) considering the impact on service provision for oral surgery in England.Methods Oral surgery referral data were available from an eRMS for areas of England covered by this service for the 34-month period of March 2019 to December 2021 (inclusive), which included 12 months of pre-pandemic data and the first 22 months of the pandemic. The data were from the following regions in England: Central Midlands; Cheshire and Merseyside; East Anglia and Essex; Greater Manchester; Lancashire; Thames Valley; and Yorkshire and the Humber.Results The total number of referrals received was 1,766,895 during this 34-month period, with pre-pandemic referral levels averaging at 25,498 per month, with a reduction to 698 per month in April 2020. Referrals have risen to a peak of 217,646 for the month of November 2021. An average of 1.5% of referrals were rejected pre-pandemic, compared with 2.7% per month post-pandemic.Discussion Pre-pandemic referral numbers were predictably stable within a narrow range which have then increased dramatically post-pandemic. The variations in oral surgery referral patterns place significant strain on oral surgery services across England. This not only has consequences on the patient experience, but also on workforce and workforce development, to ensure that there is not a long-term destabilising impact.Conclusion Analysis of 1.75 million referrals to oral surgery services in England has highlighted the ongoing impact of the pandemic and the need to actively minimise adverse impacts on patients, NHS services and the workforce.
Collapse
Affiliation(s)
- Richard J Moore
- Division of Oral Surgery and Oral Medicine, University of Leeds, UK.
| | - Iain Pretty
- School of Dentistry, University of Manchester, UK
| | - Gail V A Douglas
- Department of Dental Public Health, University of Leeds Dental School, UK
| | - Alan J Mighell
- Division of Oral Surgery and Oral Medicine, University of Leeds, UK
| |
Collapse
|
4
|
Moore RJ, Pretty I, Douglas G, Mighell AJ. An evaluation of referrer factors for 98,671 referrals made to the West Yorkshire oral surgery managed clinical network over a three-year period. Br Dent J 2022:10.1038/s41415-022-4034-z. [PMID: 35246623 PMCID: PMC8896068 DOI: 10.1038/s41415-022-4034-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 05/10/2021] [Indexed: 11/09/2022]
Abstract
Introduction Patients referred from primary dental care to hospital-based specialists in high volumes can contribute to significant NHS service pressures. Surprisingly, little is understood about what contributes to referral factors.Aims To gain new insight into the referral factors from primary dental care by interrogating the tri-speciality West Yorkshire managed clinical network (MCN) referral pathway data for a 36-month period (2016-2019).Methods Anonymised referrals from the electronic referral management system were collated for analyses.Results There were 98,671 referrals within the 36-month period, 12.3% of which were rejected. Of those accepted for triage, 76% were directed at oral surgery, with >60% accounted for by exodontia. In total, 10% of referrers accounted for 60% of all referrals. Peak referral occurred five years after General Dental Council registration.Discussion This is the first report of referral data from a tri-speciality MCN with exodontia referrals predominating. The data set demonstrates variation in referrer behaviours despite referral guidance. Referrals should be based upon patient need but patterns observed in this study suggested possible associations with high and low referral patterns which warrant further research.Conclusions Interrogation of the referral database suggests that there are interesting patterns of referral which may be associated with characteristics of the referrer as well as their patients' needs. Further investigation could inform improved processes and service design, as well as education delivery and workforce development.
Collapse
Affiliation(s)
- Richard J Moore
- Division of Oral Surgery and Oral Medicine, University of Leeds, UK.
| | - Iain Pretty
- School of Dentistry, University of Manchester, UK
| | - Gail Douglas
- Department of Dental Public Health, University of Leeds Dental School, UK
| | - Alan J Mighell
- Division of Oral Surgery and Oral Medicine, University of Leeds, UK
| |
Collapse
|
5
|
Smith CEL, Whitehouse LLE, Poulter JA, Wilkinson Hewitt L, Nadat F, Jackson BR, Manfield IW, Edwards TA, Rodd HD, Inglehearn CF, Mighell AJ. A missense variant in specificity protein 6 (SP6) is associated with amelogenesis imperfecta. Hum Mol Genet 2021; 29:1417-1425. [PMID: 32167558 PMCID: PMC7268548 DOI: 10.1093/hmg/ddaa041] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 03/03/2020] [Accepted: 03/04/2020] [Indexed: 01/01/2023] Open
Abstract
Amelogenesis is the process of enamel formation. For amelogenesis to proceed, the cells of the inner enamel epithelium (IEE) must first proliferate and then differentiate into the enamel-producing ameloblasts. Amelogenesis imperfecta (AI) is a heterogeneous group of genetic conditions that result in defective or absent tooth enamel. We identified a 2 bp variant c.817_818GC>AA in SP6, the gene encoding the SP6 transcription factor, in a Caucasian family with autosomal dominant hypoplastic AI. The resulting missense protein change, p.(Ala273Lys), is predicted to alter a DNA-binding residue in the first of three zinc fingers. SP6 has been shown to be crucial to both proliferation of the IEE and to its differentiation into ameloblasts. SP6 has also been implicated as an AI candidate gene through its study in rodent models. We investigated the effect of the missense variant in SP6 (p.(Ala273Lys)) using surface plasmon resonance protein-DNA binding studies. We identified a potential SP6 binding motif in the AMBN proximal promoter sequence and showed that wild-type (WT) SP6 binds more strongly to it than the mutant protein. We hypothesize that SP6 variants may be a very rare cause of AI due to the critical roles of SP6 in development and that the relatively mild effect of the missense variant identified in this study is sufficient to affect amelogenesis causing AI, but not so severe as to be incompatible with life. We suggest that current AI cohorts, both with autosomal recessive and dominant disease, be screened for SP6 variants.
Collapse
Affiliation(s)
- Claire E L Smith
- Division of Molecular Medicine, Leeds Institute of Medical Research, Faculty of Medicine and Health, St James's University Hospital, University of Leeds, Leeds LS9 7TF, UK
| | - Laura L E Whitehouse
- School of Dentistry, Faculty of Medicine and Health, University of Leeds, Leeds LS2 9LU, UK
| | - James A Poulter
- Division of Molecular Medicine, Leeds Institute of Medical Research, Faculty of Medicine and Health, St James's University Hospital, University of Leeds, Leeds LS9 7TF, UK
| | - Laura Wilkinson Hewitt
- Protein Production Facility, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Fatima Nadat
- Protein Production Facility, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Brian R Jackson
- Protein Production Facility, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Iain W Manfield
- Centre for Biomolecular Interactions Technology Facility, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds LS2 9JT, UK
| | - Thomas A Edwards
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Helen D Rodd
- Academic Unit of Oral Health Dentistry and Society, School of Clinical Dentistry, University of Sheffield, Sheffield, S10 2TA, UK
| | - Chris F Inglehearn
- Division of Molecular Medicine, Leeds Institute of Medical Research, Faculty of Medicine and Health, St James's University Hospital, University of Leeds, Leeds LS9 7TF, UK
| | - Alan J Mighell
- School of Dentistry, Faculty of Medicine and Health, University of Leeds, Leeds LS2 9LU, UK
| |
Collapse
|
6
|
Whitehouse LLE, Smith CEL, Poulter JA, Brown CJ, Patel A, Lamb T, Brown LR, O'Sullivan EA, Mitchell RE, Berry IR, Charlton R, Inglehearn CF, Mighell AJ. NOVEL DLX3 VARIANTS IN AMELOGENESIS IMPERFECTA WITH ATTENUATED TRICHO-DENTO-OSSEOUS SYNDROME. Oral Surg Oral Med Oral Pathol Oral Radiol 2021. [DOI: 10.1016/j.oooo.2021.03.184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
7
|
Nikolopoulos G, Smith CEL, Poulter JA, Murillo G, Silva S, Lamb T, Berry IR, Brown CJ, Day PF, Soldani F, Al-Bahlani S, Harris SA, O'Connell MJ, Inglehearn CF, Mighell AJ. Spectrum of pathogenic variants and founder effects in amelogenesis imperfecta associated with MMP20. Hum Mutat 2021; 42:567-576. [PMID: 33600052 DOI: 10.1002/humu.24187] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 02/08/2021] [Accepted: 02/14/2021] [Indexed: 11/12/2022]
Abstract
Amelogenesis imperfecta (AI) describes a heterogeneous group of developmental enamel defects that typically have Mendelian inheritance. Exome sequencing of 10 families with recessive hypomaturation AI revealed four novel and one known variants in the matrix metallopeptidase 20 (MMP20) gene that were predicted to be pathogenic. MMP20 encodes a protease that cleaves the developing extracellular enamel matrix and is necessary for normal enamel crystal growth during amelogenesis. New homozygous missense changes were shared between four families of Pakistani heritage (c.625G>C; p.(Glu209Gln)) and two of Omani origin (c.710C>A; p.(Ser237Tyr)). In two families of UK origin and one from Costa Rica, affected individuals were homozygous for the previously reported c.954-2A>T; p.(Ile319Phefs*19) variant. For each of these variants, microsatellite haplotypes appeared to exclude a recent founder effect, but elements of haplotype were conserved, suggesting more distant founding ancestors. New compound heterozygous changes were identified in one family of the European heritage: c.809_811+12delinsCCAG; p.(?) and c.1122A>C; p.(Gln374His). This report further elucidates the mutation spectrum of MMP20 and the probable impact on protein function, confirms a consistent hypomaturation phenotype and shows that mutations in MMP20 are a common cause of autosomal recessive AI in some communities.
Collapse
Affiliation(s)
- Georgios Nikolopoulos
- Division of Molecular Medicine, Leeds Institute of Medical Research, University of Leeds, Leeds, UK.,Department of Oral Biology, School of Dentistry, St James's University Hospital, University of Leeds, Leeds, UK
| | - Claire E L Smith
- Division of Molecular Medicine, Leeds Institute of Medical Research, University of Leeds, Leeds, UK
| | - James A Poulter
- Division of Molecular Medicine, Leeds Institute of Medical Research, University of Leeds, Leeds, UK
| | - Gina Murillo
- School of Dentistry, Universidad de Costa Rica, Ciudad Universitaria Rodrigo Facio, San Pedro Montes De Oca, Costa Rica
| | - Sandra Silva
- Cellular and Molecular Biology Centre (CBCM), Universidad de Costa Rica, Ciudad Universitaria Rodrigo Facio, San Pedro Montes De Oca, Costa Rica
| | - Teresa Lamb
- Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Ian R Berry
- Leeds Genetics Laboratory, St James's University Hospital, Leeds, UK
| | | | - Peter F Day
- Department of Paediatric Dentistry, Leeds Dental Institute, University of Leeds, Leeds, UK.,Community Dental Service, Horton Park Health Centre, Bradford District Care NHS Foundation Trust, Bradford, UK
| | - Francesca Soldani
- Community Dental Service, Horton Park Health Centre, Bradford District Care NHS Foundation Trust, Bradford, UK
| | - Suhaila Al-Bahlani
- Dental & O.M.F.S Clinic, Al Nahdha Hospital, Ministry of Health, Muscat, Oman
| | - Sarah A Harris
- School of Physics, University of Leeds, Leeds, UK.,Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
| | - Mary J O'Connell
- School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK.,School of Life Sciences, Faculty of Medicine and Health Sciences, University of Nottingham, Nottingham, UK
| | - Chris F Inglehearn
- Division of Molecular Medicine, Leeds Institute of Medical Research, University of Leeds, Leeds, UK
| | - Alan J Mighell
- Department of Oral Biology, School of Dentistry, St James's University Hospital, University of Leeds, Leeds, UK
| |
Collapse
|
8
|
Sato K, Mogi C, Mighell AJ, Okajima F. A missense mutation of Leu74Pro of OGR1 found in familial amelogenesis imperfecta actually causes the loss of the pH-sensing mechanism. Biochem Biophys Res Commun 2020; 526:920-926. [DOI: 10.1016/j.bbrc.2020.04.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 04/02/2020] [Indexed: 02/06/2023]
|
9
|
Nikolopoulos G, Smith CEL, Brookes SJ, El-Asrag ME, Brown CJ, Patel A, Murillo G, O'Connell MJ, Inglehearn CF, Mighell AJ. New missense variants in RELT causing hypomineralised amelogenesis imperfecta. Clin Genet 2020; 97:688-695. [PMID: 32052416 PMCID: PMC7216828 DOI: 10.1111/cge.13721] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 02/04/2020] [Accepted: 02/05/2020] [Indexed: 12/18/2022]
Abstract
Amelogenesis imperfecta (AI) is a heterogeneous group of genetic diseases characterised by dental enamel malformation. Pathogenic variants in at least 33 genes cause syndromic or non-syndromic AI. Recently variants in RELT, encoding an orphan receptor in the tumour necrosis factor (TNF) superfamily, were found to cause recessive AI, as part of a syndrome encompassing small stature and severe childhood infections. Here we describe four additional families with autosomal recessive hypomineralised AI due to previously unreported homozygous mutations in RELT. Three families carried a homozygous missense variant in the fourth exon (c.164C>T, p.(T55I)) and a fourth family carried a homozygous missense variant in the 11th exon (c.1264C>T, p.(R422W)). We found no evidence of additional syndromic symptoms in affected individuals. Analyses of tooth microstructure with computerised tomography and scanning electron microscopy suggest a role for RELT in ameloblasts' coordination and interaction with the enamel matrix. Microsatellite genotyping in families segregating the T55I variant reveals a shared founder haplotype. These findings extend the RELT pathogenic variant spectrum, reveal a founder mutation in the UK Pakistani population and provide detailed analysis of human teeth affected by this hypomineralised phenotype, but do not support a possible syndromic presentation in all those with RELT-variant associated AI.
Collapse
Affiliation(s)
- Georgios Nikolopoulos
- Division of Molecular Medicine, Leeds Institute of Medical Research, The University of Leeds, Leeds, UK.,Department of Oral Biology, School of Dentistry, St James's University Hospital, The University of Leeds, Leeds, UK
| | - Claire E L Smith
- Division of Molecular Medicine, Leeds Institute of Medical Research, The University of Leeds, Leeds, UK
| | - Steven J Brookes
- Department of Oral Biology, School of Dentistry, St James's University Hospital, The University of Leeds, Leeds, UK
| | - Mohammed E El-Asrag
- Division of Molecular Medicine, Leeds Institute of Medical Research, The University of Leeds, Leeds, UK.,Division of Cardiovascular Sciences, School of Medicine, Faculty of Biology Medicine and Health, University of Manchester, Manchester, UK.,Department of Zoology, Faculty of Science, Benha University, Benha, Egypt
| | - Catriona J Brown
- Birmingham Dental Hospital, Mill Pool Way, Edgbaston, Birmingham, UK
| | - Anesha Patel
- Birmingham Dental Hospital, Mill Pool Way, Edgbaston, Birmingham, UK
| | - Gina Murillo
- School of Dentistry, Ciudad Universitaria Rodrigo Facio, Montes De Oca, Universidad de Costa Rica, San Jose, Costa Rica
| | - Mary J O'Connell
- School of Biology, Faculty of Biological Sciences, The University of Leeds, Leeds, UK.,School of Life Sciences, Faculty of Medicine and Health Sciences, The University of Nottingham, Nottingham, UK
| | - Chris F Inglehearn
- Division of Molecular Medicine, Leeds Institute of Medical Research, The University of Leeds, Leeds, UK
| | - Alan J Mighell
- Department of Oral Biology, School of Dentistry, St James's University Hospital, The University of Leeds, Leeds, UK
| |
Collapse
|
10
|
Whitehouse LLE, Smith CEL, Poulter JA, Brown CJ, Patel A, Lamb T, Brown LR, O’Sullivan EA, Mitchell RE, Berry IR, Charlton R, Inglehearn CF, Mighell AJ. Novel DLX3 variants in amelogenesis imperfecta with attenuated tricho-dento-osseous syndrome. Oral Dis 2019; 25:182-191. [PMID: 30095208 PMCID: PMC6334507 DOI: 10.1111/odi.12955] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 07/12/2018] [Accepted: 08/03/2018] [Indexed: 12/20/2022]
Abstract
OBJECTIVES Variants in DLX3 cause tricho-dento-osseous syndrome (TDO, MIM #190320), a systemic condition with hair, nail and bony changes, taurodontism and amelogenesis imperfecta (AI), inherited in an autosomal dominant fashion. Different variants found within this gene are associated with different phenotypic presentations. To date, six different DLX3 variants have been reported in TDO. The aim of this paper was to explore and discuss three recently uncovered new variants in DLX3. SUBJECTS AND METHODS Whole-exome sequencing identified a new DLX3 variant in one family, recruited as part of an ongoing study of genetic variants associated with AI. Targeted clinical exome sequencing of two further families revealed another new variant of DLX3 and complete heterozygous deletion of DLX3. For all three families, the phenotypes were shown to consist of AI and taurodontism, together with other attenuated features of TDO. RESULTS c.574delG p.(E192Rfs*66), c.476G>T (p.R159L) and a heterozygous deletion of the entire DLX3 coding region were identified in our families. CONCLUSION These previously unreported variants add to the growing literature surrounding AI, allowing for more accurate genetic testing and better understanding of the associated clinical consequences.
Collapse
Affiliation(s)
| | - Claire E. L. Smith
- Section of Ophthalmology and Neuroscience, Leeds Institute of Biomedical and Clinical SciencesUniversity of LeedsLeedsUK
| | | | | | - Anesha Patel
- Birmingham Dental Hospital and School of DentistryBirminghamUK
| | - Teresa Lamb
- Oxford University Hospitals NHS Foundation TrustOxfordUK
| | | | | | | | - Ian R. Berry
- Leeds Genetics LaboratorySt James’s University HospitalLeedsUK
| | - Ruth Charlton
- Leeds Genetics LaboratorySt James’s University HospitalLeedsUK
| | - Chris F. Inglehearn
- Section of Ophthalmology and Neuroscience, Leeds Institute of Biomedical and Clinical SciencesUniversity of LeedsLeedsUK
| | | |
Collapse
|
11
|
Mighell AJ, Freeman C, Atkin PA, Bennett JH, Buchanan JAG, Carrozzo M, Crighton AJ, Escudier MP, Gibson J, Healy CM, Hegarty AM, Kerr JS, McCreary CE, Pemberton MN, Rajlawat B, Richards A, Staines K, Theaker ED, Willis A. Oral Medicine for undergraduate dental students in the United Kingdom and Ireland-A curriculum. Eur J Dent Educ 2018; 22:e661-e668. [PMID: 29877053 DOI: 10.1111/eje.12366] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 04/29/2018] [Indexed: 06/08/2023]
Abstract
INTRODUCTION Oral Medicine focuses on care for patients with chronic, recurrent and medically related disorders of the orofacial region that are distinct from diseases of the periodontal and tooth tissues, with an emphasis on non-surgical management. At present, there are no shared outcomes for Oral Medicine to define the standards to be achieved before new graduates become registered dentists engaged with ongoing professional development. CURRICULUM We present a consensus undergraduate curriculum in Oral Medicine agreed by representatives from 18 Dental Schools in the United Kingdom and Republic of Ireland. The scope of Oral Medicine practice includes conditions involving the oral mucosa, salivary glands, neurological system or musculoskeletal tissues that are not directly attributable to dental (tooth and periodontium) pathology. Account is taken of the priorities for practice and learning opportunities needed to support development of relevance to independent clinical practice. The outcomes triangulate with the requirements set out by the respective regulatory bodies in the UK and Republic of Ireland prior to first registration and are consistent with the framework for European undergraduate dental education and greater harmonisation of dental education. CONCLUSIONS This curriculum will act as a foundation for an increasingly shared approach between centres with respect to the outcomes to be achieved in Oral Medicine. The curriculum may also be of interest to others, such as those responsible for the training of dental hygienists and dental therapists. It provides a platform for future collective developments with the overarching goal of raising the quality of patient care.
Collapse
Affiliation(s)
| | - C Freeman
- The University of Sheffield, Sheffield, UK
| | | | | | | | - M Carrozzo
- The University of Newcastle, Newcastle, UK
| | | | - M P Escudier
- The University of London (Kings College), London, UK
| | - J Gibson
- The University of Glasgow, Glasgow, UK
| | - C M Healy
- The University of Dublin, Dublin, Ireland
| | | | - J S Kerr
- University of Central Lancashire, Preston, UK
| | | | | | - B Rajlawat
- The University of Liverpool, Liverpool, UK
| | - A Richards
- The University of Birmingham, Birmingham, UK
| | - K Staines
- The University of Bristol, Bristol, UK
| | | | - A Willis
- Queen's University Belfast, Belfast, UK
| |
Collapse
|
12
|
Atkin PA, Thomas S, Cook RJ, Greenwood M, Bennett JH, Willis A, Donachie C, Ni Riordain R, Galvin S, Crighton A, Mighell AJ, Bakri I. Human Disease/Clinical Medical Sciences in Dentistry: Current state and future directions of undergraduate teaching in the UK and Ireland. Eur J Dent Educ 2018; 22:e588-e593. [PMID: 29667358 DOI: 10.1111/eje.12356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 03/27/2018] [Indexed: 06/08/2023]
Abstract
In March 2017, a group of teachers of human disease/clinical medical science (HD/CMSD) representing the majority of schools from around the UK and Republic of Ireland met to discuss the current state of teaching of human disease and also to discuss how the delivery of this theme might evolve to inform improved healthcare. This study outlines how the original teaching in medicine and surgery to dental undergraduate students has developed into the theme of HD/CMSD reflecting changing needs as well as guidance from the regulators, and how different dental schools have developed their approaches to reach their current state. Each school was also asked to share a strengths, weakness, opportunities and threats (SWOT) analysis of their programme and to outline how they thought their HD/CMSD programme may develop. The school representatives who coordinate the delivery and assessment of HD/CMSD in the undergraduate curriculum have extensive insight in this area and are well-placed to shape the HD/CMSD development for the future.
Collapse
Affiliation(s)
- P A Atkin
- Department of Oral Medicine, Cardiff University, Cardiff, UK
| | - S Thomas
- Department of Oral & Maxillofacial Surgery, Bristol University, Bristol, UK
| | - R J Cook
- Department of Oral Medicine, King's College London, London, UK
| | - M Greenwood
- Department of Oral & Maxillofacial Surgery, Newcastle University, Newcastle, UK
| | - J H Bennett
- Department of Integrated Dental Sciences, Plymouth University, Plymouth, UK
| | - A Willis
- Department of Oral Medicine, Queens University Belfast, Belfast, UK
| | - C Donachie
- Department of Special Care Dentistry, University of Aberdeen, Aberdeen, UK
| | - R Ni Riordain
- Department of Oral Medicine, University College Cork, Cork, UK
| | - S Galvin
- Department of Oral Medicine, University of Dublin, Dublin, UK
| | - A Crighton
- Department of Oral Medicine, University of Glasgow, Glasgow, UK
| | - A J Mighell
- Department of Oral Medicine, University of Leeds, Leeds, UK
| | - I Bakri
- Department of Oral Surgery, University of Sheffield, Sheffield, UK
| |
Collapse
|
13
|
Abstract
Dentin dysplasia(DD) is a rare autosomal dominant disorder associated with disturbance of the dentin. While the crowns appear clinically normal, on radiography, the pulp spaces appear partially or completely obliterated, with short blunted roots, and multiple periapical radiolucencies affecting the apparently sound teeth. Clinical signs include spontaneous abscess formation or increased tooth mobility which can lead to exfoliation. DD can therefore have a significant impact on the patient's dentition, and treatment is often challenging. Shields' classification of dentin disorders has been recently criticised for failing to consider differential variations and expressions of these disorders. This paper describes a case of a 23-year-old woman with previously undiagnosed DD, who presented with clinical and histological features belonging to several of these diseases, thus highlighting the potential diagnostic challenges faced with Shields' classification.
Collapse
Affiliation(s)
- Ahmed Alhilou
- Restorative Dentistry, Leeds Dental Institute, Leeds, West Yorkshire, UK
| | - Hannah P Beddis
- Restorative Dentistry, Leeds Dental Institute, Leeds, West Yorkshire, UK
| | | | - Kathryn Durey
- Restorative Dentistry, Leeds Dental Institute, Leeds, West Yorkshire, UK
| |
Collapse
|
14
|
Brookes SJ, Barron MJ, Smith CEL, Poulter JA, Mighell AJ, Inglehearn CF, Brown CJ, Rodd H, Kirkham J, Dixon MJ. Amelogenesis imperfecta caused by N-terminal enamelin point mutations in mice and men is driven by endoplasmic reticulum stress. Hum Mol Genet 2017; 26:1863-1876. [PMID: 28334996 PMCID: PMC5411757 DOI: 10.1093/hmg/ddx090] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 03/02/2017] [Indexed: 12/30/2022] Open
Abstract
‘Amelogenesis imperfecta’ (AI) describes a group of inherited diseases of dental enamel that have major clinical impact. Here, we identify the aetiology driving AI in mice carrying a p.S55I mutation in enamelin; one of the most commonly mutated proteins underlying AI in humans. Our data indicate that the mutation inhibits the ameloblast secretory pathway leading to ER stress and an activated unfolded protein response (UPR). Initially, with the support of the UPR acting in pro-survival mode, Enamp.S55I heterozygous mice secreted structurally normal enamel. However, enamel secreted thereafter was structurally abnormal; presumably due to the UPR modulating ameloblast behaviour and function in an attempt to relieve ER stress. Homozygous mutant mice failed to produce enamel. We also identified a novel heterozygous ENAMp.L31R mutation causing AI in humans. We hypothesize that ER stress is the aetiological factor in this case of human AI as it shared the characteristic phenotype described above for the Enamp.S55I mouse. We previously demonstrated that AI in mice carrying the Amelxp.Y64H mutation is a proteinopathy. The current data indicate that AI in Enamp.S55I mice is also a proteinopathy, and based on comparative phenotypic analysis, we suggest that human AI resulting from the ENAMp.L31R mutation is another proteinopathic disease. Identifying a common aetiology for AI resulting from mutations in two different genes opens the way for developing pharmaceutical interventions designed to relieve ER stress or modulate the UPR during enamel development to ameliorate the clinical phenotype.
Collapse
Affiliation(s)
- Steven J Brookes
- Department of Oral Biology, School of Dentistry, Wellcome Trust Brenner Building University Of Leeds, St James's University Hospital, Leeds LS9 7TF, UK
| | - Martin J Barron
- Faculty of Biology, Medicine & Health, Manchester Academic Health Sciences Centre, University of Manchester, Michael Smith Building, Manchester M13 9PT, UK
| | - Claire E L Smith
- Department of Oral Medicine, School of Dentistry, University of Leeds, Leeds, UK
| | - James A Poulter
- Department of Oral Medicine, School of Dentistry, University of Leeds, Leeds, UK
| | - Alan J Mighell
- Leeds Institute of Biomedical and Clinical Sciences, St James's University Hospital, University of Leeds, Leeds LS9 7TF, UK
| | - Chris F Inglehearn
- Department of Oral Medicine, School of Dentistry, University of Leeds, Leeds, UK
| | - Catriona J Brown
- Birmingham Dental Hospital and School of Dentistry, Birmingham B5 7EG, UK
| | - Helen Rodd
- Unit of Oral Health and Development, School of Clinical Dentistry, University of Sheffield, Sheffield, UK
| | - Jennifer Kirkham
- Department of Oral Biology, School of Dentistry, Wellcome Trust Brenner Building University Of Leeds, St James's University Hospital, Leeds LS9 7TF, UK
| | - Michael J Dixon
- Faculty of Biology, Medicine & Health, Manchester Academic Health Sciences Centre, University of Manchester, Michael Smith Building, Manchester M13 9PT, UK
| |
Collapse
|
15
|
Smith CEL, Poulter JA, Antanaviciute A, Kirkham J, Brookes SJ, Inglehearn CF, Mighell AJ. Amelogenesis Imperfecta; Genes, Proteins, and Pathways. Front Physiol 2017; 8:435. [PMID: 28694781 PMCID: PMC5483479 DOI: 10.3389/fphys.2017.00435] [Citation(s) in RCA: 143] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 06/08/2017] [Indexed: 01/11/2023] Open
Abstract
Amelogenesis imperfecta (AI) is the name given to a heterogeneous group of conditions characterized by inherited developmental enamel defects. AI enamel is abnormally thin, soft, fragile, pitted and/or badly discolored, with poor function and aesthetics, causing patients problems such as early tooth loss, severe embarrassment, eating difficulties, and pain. It was first described separately from diseases of dentine nearly 80 years ago, but the underlying genetic and mechanistic basis of the condition is only now coming to light. Mutations in the gene AMELX, encoding an extracellular matrix protein secreted by ameloblasts during enamel formation, were first identified as a cause of AI in 1991. Since then, mutations in at least eighteen genes have been shown to cause AI presenting in isolation of other health problems, with many more implicated in syndromic AI. Some of the encoded proteins have well documented roles in amelogenesis, acting as enamel matrix proteins or the proteases that degrade them, cell adhesion molecules or regulators of calcium homeostasis. However, for others, function is less clear and further research is needed to understand the pathways and processes essential for the development of healthy enamel. Here, we review the genes and mutations underlying AI presenting in isolation of other health problems, the proteins they encode and knowledge of their roles in amelogenesis, combining evidence from human phenotypes, inheritance patterns, mouse models, and in vitro studies. An LOVD resource (http://dna2.leeds.ac.uk/LOVD/) containing all published gene mutations for AI presenting in isolation of other health problems is described. We use this resource to identify trends in the genes and mutations reported to cause AI in the 270 families for which molecular diagnoses have been reported by 23rd May 2017. Finally we discuss the potential value of the translation of AI genetics to clinical care with improved patient pathways and speculate on the possibility of novel treatments and prevention strategies for AI.
Collapse
Affiliation(s)
- Claire E L Smith
- Division of Oral Biology, School of Dentistry, St. James's University Hospital, University of LeedsLeeds, United Kingdom.,Section of Ophthalmology and Neuroscience, St. James's University Hospital, University of LeedsLeeds, United Kingdom
| | - James A Poulter
- Section of Ophthalmology and Neuroscience, St. James's University Hospital, University of LeedsLeeds, United Kingdom
| | - Agne Antanaviciute
- Section of Genetics, School of Medicine, St. James's University Hospital, University of LeedsLeeds, United Kingdom
| | - Jennifer Kirkham
- Division of Oral Biology, School of Dentistry, St. James's University Hospital, University of LeedsLeeds, United Kingdom
| | - Steven J Brookes
- Division of Oral Biology, School of Dentistry, St. James's University Hospital, University of LeedsLeeds, United Kingdom
| | - Chris F Inglehearn
- Section of Ophthalmology and Neuroscience, St. James's University Hospital, University of LeedsLeeds, United Kingdom
| | - Alan J Mighell
- Section of Ophthalmology and Neuroscience, St. James's University Hospital, University of LeedsLeeds, United Kingdom.,Oral Medicine, School of Dentistry, University of LeedsLeeds, United Kingdom
| |
Collapse
|
16
|
Smith CEL, Kirkham J, Day PF, Soldani F, McDerra EJ, Poulter JA, Inglehearn CF, Mighell AJ, Brookes SJ. A Fourth KLK4 Mutation Is Associated with Enamel Hypomineralisation and Structural Abnormalities. Front Physiol 2017; 8:333. [PMID: 28611678 PMCID: PMC5447068 DOI: 10.3389/fphys.2017.00333] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 05/08/2017] [Indexed: 12/30/2022] Open
Abstract
“Amelogenesis imperfecta” (AI) describes a group of genetic conditions that result in defects in tooth enamel formation. Mutations in many genes are known to cause AI, including the gene encoding the serine protease, kallikrein related peptidase 4 (KLK4), expressed during the maturation stage of amelogenesis. In this study we report the fourth KLK4 mutation to be identified in autosomal recessively-inherited hypomaturation type AI, c.632delT, p.(L211Rfs*37) (NM_004917.4, NP_004908.4). This homozygous variant was identified in five Pakistani AI families and is predicted to result in a transcript with a premature stop codon that escapes nonsense mediated decay. However, the protein may misfold, as three of six disulphide bonds would be disrupted, and may be degraded or non-functional as a result. Primary teeth were obtained from one affected individual. The enamel phenotype was characterized using high-resolution computerized X-ray tomography (CT), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and microhardness testing (MH). Enamel from the affected individual (referred to as KLK4 enamel) was hypomineralised in comparison with matched control enamel. Furthermore, KLK4 inner enamel was hypomineralised compared with KLK4 outer enamel. SEM showed a clear structural demarcation between KLK4 inner and outer enamel, although enamel structure was similar to control tissue overall. EDX showed that KLK4 inner enamel contained less calcium and phosphorus and more nitrogen than control inner enamel and KLK4 outer enamel. MH testing showed that KLK4 inner enamel was significantly softer than KLK4 outer enamel (p < 0.001). However, the hardness of control inner enamel was not significantly different to that of control outer enamel. Overall, these findings suggest that the KLK4 c.632delT mutation may be a common cause of autosomal recessive AI in the Pakistani population. The phenotype data obtained mirror findings in the Klk4−/− mouse and suggest that KLK4 is required for the hardening and mineralization of the inner enamel layer but is less essential for hardening and mineralization of the outer enamel layer.
Collapse
Affiliation(s)
- Claire E L Smith
- Department of Oral Biology, School of Dentistry, St James's University Hospital, University of LeedsLeeds, United Kingdom.,Section of Ophthalmology and Neuroscience, St James's University Hospital, University of LeedsLeeds, United Kingdom
| | - Jennifer Kirkham
- Department of Oral Biology, School of Dentistry, St James's University Hospital, University of LeedsLeeds, United Kingdom
| | - Peter F Day
- School of Dentistry, University of LeedsLeeds, United Kingdom.,Bradford District Care NHS Foundation Trust, Community Dental Service, Horton Park Health CentreBradford, United Kingdom
| | - Francesca Soldani
- Bradford District Care NHS Foundation Trust, Community Dental Service, Horton Park Health CentreBradford, United Kingdom
| | - Esther J McDerra
- School of Dentistry, University of LeedsLeeds, United Kingdom.,Locala Dental Care, Dental Department, Batley Health CentreBatley, United Kingdom
| | - James A Poulter
- Section of Ophthalmology and Neuroscience, St James's University Hospital, University of LeedsLeeds, United Kingdom
| | - Christopher F Inglehearn
- Section of Ophthalmology and Neuroscience, St James's University Hospital, University of LeedsLeeds, United Kingdom
| | - Alan J Mighell
- Section of Ophthalmology and Neuroscience, St James's University Hospital, University of LeedsLeeds, United Kingdom.,School of Dentistry, University of LeedsLeeds, United Kingdom
| | - Steven J Brookes
- Department of Oral Biology, School of Dentistry, St James's University Hospital, University of LeedsLeeds, United Kingdom
| |
Collapse
|
17
|
Smith CE, Whitehouse LLE, Poulter JA, Brookes SJ, Day PF, Soldani F, Kirkham J, Inglehearn CF, Mighell AJ. Defects in the acid phosphatase ACPT cause recessive hypoplastic amelogenesis imperfecta. Eur J Hum Genet 2017; 25:1015-1019. [PMID: 28513613 PMCID: PMC5511509 DOI: 10.1038/ejhg.2017.79] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 03/03/2017] [Accepted: 04/05/2017] [Indexed: 11/09/2022] Open
Abstract
We identified two homozygous missense variants (c.428C>T, p.(T143M) and c.746C>T, p.(P249L)) in ACPT, the gene encoding acid phosphatase, testicular, which segregates with hypoplastic amelogenesis imperfecta in two unrelated families. ACPT is reported to play a role in odontoblast differentiation and mineralisation by supplying phosphate during dentine formation. Analysis by computerised tomography and scanning electron microscopy of a primary molar tooth from an individual homozygous for the c.746C>T variant revealed an enamel layer that was hypoplastic, but mineralised with prismatic architecture. These findings implicate variants in ACPT as a cause of early failure of amelogenesis during the secretory phase.
Collapse
Affiliation(s)
- Claire El Smith
- Department of Oral Biology, School of Dentistry, St James's University Hospital, University of Leeds, Leeds, UK.,Leeds Institute of Biomedical and Clinical Sciences, St. James's University Hospital, University of Leeds, Leeds, UK
| | - Laura LE Whitehouse
- Leeds Institute of Biomedical and Clinical Sciences, St. James's University Hospital, University of Leeds, Leeds, UK
| | - James A Poulter
- Leeds Institute of Biomedical and Clinical Sciences, St. James's University Hospital, University of Leeds, Leeds, UK
| | - Steven J Brookes
- Department of Oral Biology, School of Dentistry, St James's University Hospital, University of Leeds, Leeds, UK
| | - Peter F Day
- School of Dentistry, University of Leeds, Leeds, UK.,Bradford District Care NHS Foundation Trust, Community Dental Service, Horton Park Health Centre, Bradford, UK
| | - Francesca Soldani
- Bradford District Care NHS Foundation Trust, Community Dental Service, Horton Park Health Centre, Bradford, UK
| | - Jennifer Kirkham
- Department of Oral Biology, School of Dentistry, St James's University Hospital, University of Leeds, Leeds, UK
| | - Chris F Inglehearn
- Leeds Institute of Biomedical and Clinical Sciences, St. James's University Hospital, University of Leeds, Leeds, UK
| | - Alan J Mighell
- Leeds Institute of Biomedical and Clinical Sciences, St. James's University Hospital, University of Leeds, Leeds, UK.,School of Dentistry, University of Leeds, Leeds, UK
| |
Collapse
|
18
|
Parry DA, Smith CE, El-Sayed W, Poulter JA, Shore RC, Logan CV, Mogi C, Sato K, Okajima F, Harada A, Zhang H, Koruyucu M, Seymen F, Hu JCC, Simmer JP, Ahmed M, Jafri H, Johnson CA, Inglehearn CF, Mighell AJ. Mutations in the pH-Sensing G-protein-Coupled Receptor GPR68 Cause Amelogenesis Imperfecta. Am J Hum Genet 2016; 99:984-990. [PMID: 27693231 PMCID: PMC5065684 DOI: 10.1016/j.ajhg.2016.08.020] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 08/17/2016] [Indexed: 01/11/2023] Open
Abstract
Amelogenesis is the process of dental enamel formation, leading to the deposition of the hardest tissue in the human body. This process requires the intricate regulation of ion transport and controlled changes to the pH of the developing enamel matrix. The means by which the enamel organ regulates pH during amelogenesis is largely unknown. We identified rare homozygous variants in GPR68 in three families with amelogenesis imperfecta, a genetically and phenotypically heterogeneous group of inherited conditions associated with abnormal enamel formation. Each of these homozygous variants (a large in-frame deletion, a frameshift deletion, and a missense variant) were predicted to result in loss of function. GPR68 encodes a proton-sensing G-protein-coupled receptor with sensitivity in the pH range that occurs in the developing enamel matrix during amelogenesis. Immunohistochemistry of rat mandibles confirmed localization of GPR68 in the enamel organ at all stages of amelogenesis. Our data identify a role for GPR68 as a proton sensor that is required for proper enamel formation.
Collapse
|
19
|
Smith CEL, Murillo G, Brookes SJ, Poulter JA, Silva S, Kirkham J, Inglehearn CF, Mighell AJ. Deletion of amelotin exons 3-6 is associated with amelogenesis imperfecta. Hum Mol Genet 2016; 25:3578-3587. [PMID: 27412008 PMCID: PMC5179951 DOI: 10.1093/hmg/ddw203] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 06/17/2016] [Accepted: 06/21/2016] [Indexed: 11/15/2022] Open
Abstract
Amelogenesis imperfecta (AI) is a heterogeneous group of genetic conditions that result in defective dental enamel formation. Amelotin (AMTN) is a secreted protein thought to act as a promoter of matrix mineralization in the final stage of enamel development, and is strongly expressed, almost exclusively, in maturation stage ameloblasts. Amtn overexpression and Amtn knockout mouse models have defective enamel with no other associated phenotypes, highlighting AMTN as an excellent candidate gene for human AI. However, no AMTN mutations have yet been associated with human AI. Using whole exome sequencing, we identified an 8,678 bp heterozygous genomic deletion encompassing exons 3-6 of AMTN in a Costa Rican family segregating dominant hypomineralised AI. The deletion corresponds to an in-frame deletion of 92 amino acids, shortening the protein from 209 to 117 residues. Exfoliated primary teeth from an affected family member had enamel that was of a lower mineral density compared to control enamel and exhibited structural defects at least some of which appeared to be associated with organic material as evidenced using elemental analysis. This study demonstrates for the first time that AMTN mutations cause non-syndromic human AI and explores the human phenotype, comparing it with that of mice with disrupted Amtn function.
Collapse
Affiliation(s)
- Claire E L Smith
- Leeds Institute of Biomedical and Clinical Sciences, St James's University Hospital, University of Leeds, Leeds LS9 7TF, UK.,Department of Oral Biology, St James's University Hospital, University of Leeds, Leeds LS9 7TF, UK
| | - Gina Murillo
- University of Costa Rica, School of Dentistry, San Pedro, Costa Rica
| | - Steven J Brookes
- Department of Oral Biology, St James's University Hospital, University of Leeds, Leeds LS9 7TF, UK
| | - James A Poulter
- Leeds Institute of Biomedical and Clinical Sciences, St James's University Hospital, University of Leeds, Leeds LS9 7TF, UK
| | - Sandra Silva
- University of Costa Rica, Molecular Biology Cellular Centre (CBCM), San Pedro, Costa Rica and
| | - Jennifer Kirkham
- Department of Oral Biology, St James's University Hospital, University of Leeds, Leeds LS9 7TF, UK
| | - Chris F Inglehearn
- Leeds Institute of Biomedical and Clinical Sciences, St James's University Hospital, University of Leeds, Leeds LS9 7TF, UK
| | - Alan J Mighell
- Leeds Institute of Biomedical and Clinical Sciences, St James's University Hospital, University of Leeds, Leeds LS9 7TF, UK, .,School of Dentistry, University of Leeds, Leeds LS2 9LU, UK
| |
Collapse
|
20
|
Smith CEL, Poulter JA, Levin AV, Capasso JE, Price S, Ben-Yosef T, Sharony R, Newman WG, Shore RC, Brookes SJ, Mighell AJ, Inglehearn CF. Spectrum of PEX1 and PEX6 variants in Heimler syndrome. Eur J Hum Genet 2016; 24:1565-1571. [PMID: 27302843 PMCID: PMC5026821 DOI: 10.1038/ejhg.2016.62] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 04/12/2016] [Accepted: 04/27/2016] [Indexed: 12/30/2022] Open
Abstract
Heimler syndrome (HS) consists of recessively inherited sensorineural hearing loss, amelogenesis imperfecta (AI) and nail abnormalities, with or without visual defects. Recently HS was shown to result from hypomorphic mutations in PEX1 or PEX6, both previously implicated in Zellweger Syndrome Spectrum Disorders (ZSSD). ZSSD are a group of conditions consisting of craniofacial and neurological abnormalities, sensory defects and multi-organ dysfunction. The finding of HS-causing mutations in PEX1 and PEX6 shows that HS represents the mild end of the ZSSD spectrum, though these conditions were previously thought to be distinct nosological entities. Here, we present six further HS families, five with PEX6 variants and one with PEX1 variants, and show the patterns of Pex1, Pex14 and Pex6 immunoreactivity in the mouse retina. While Ratbi et al. found more HS-causing mutations in PEX1 than in PEX6, as is the case for ZSSD, in this cohort PEX6 variants predominate, suggesting both genes play a significant role in HS. The PEX6 variant c.1802G>A, p.(R601Q), reported previously in compound heterozygous state in one HS and three ZSSD cases, was found in compound heterozygous state in three HS families. Haplotype analysis suggests a common founder variant. All families segregated at least one missense variant, consistent with the hypothesis that HS results from genotypes including milder hypomorphic alleles. The clinical overlap of HS with the more common Usher syndrome and lack of peroxisomal abnormalities on plasma screening suggest that HS may be under-diagnosed. Recognition of AI is key to the accurate diagnosis of HS.
Collapse
Affiliation(s)
- Claire E L Smith
- Leeds Institute of Biomedical and Clinical Sciences, St. James's University Hospital, University of Leeds, Leeds, UK
| | - James A Poulter
- Leeds Institute of Biomedical and Clinical Sciences, St. James's University Hospital, University of Leeds, Leeds, UK
| | - Alex V Levin
- Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA, USA.,Children's Hospital of the King's Daughters, Norfolk, VA, USA.,Pediatric Ophthalmology and Ocular Genetics, Philadelphia, PA, USA
| | - Jenina E Capasso
- Pediatric Ophthalmology and Ocular Genetics, Philadelphia, PA, USA
| | - Susan Price
- Department of Clinical Genetics, Northampton General Hospital, NHS Trust, Northampton, UK
| | | | - Reuven Sharony
- The Genetic Institute and Obstetrics and Gynaecology Department, Meir Medical Center, Kfar Saba, Israel
| | - William G Newman
- Manchester Centre for Genomic Medicine, St. Mary's Hospital, Manchester Academic Health Sciences Centre, Manchester, UK.,Manchester Centre for Genomic Medicine, Institute of Human Development, University of Manchester, Manchester, UK
| | - Roger C Shore
- School of Dentistry, Department of Oral Biology, St. James's University Hospital, University of Leeds, Leeds, UK
| | - Steven J Brookes
- School of Dentistry, Department of Oral Biology, St. James's University Hospital, University of Leeds, Leeds, UK
| | - Alan J Mighell
- Leeds Institute of Biomedical and Clinical Sciences, St. James's University Hospital, University of Leeds, Leeds, UK.,Department of Oral Medicine, School of Dentistry, University of Leeds, Leeds, UK
| | - Chris F Inglehearn
- Leeds Institute of Biomedical and Clinical Sciences, St. James's University Hospital, University of Leeds, Leeds, UK
| |
Collapse
|
21
|
Parry DA, Holmes TD, Gamper N, El-Sayed W, Hettiarachchi NT, Ahmed M, Cook GP, Logan CV, Johnson CA, Joss S, Peers C, Prescott K, Savic S, Inglehearn CF, Mighell AJ. A homozygous STIM1 mutation impairs store-operated calcium entry and natural killer cell effector function without clinical immunodeficiency. J Allergy Clin Immunol 2015; 137:955-7.e8. [PMID: 26560041 PMCID: PMC4775071 DOI: 10.1016/j.jaci.2015.08.051] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 08/07/2015] [Accepted: 08/25/2015] [Indexed: 11/25/2022]
Affiliation(s)
- David A Parry
- Section of Ophthalmology and Neuroscience, School of Medicine, St James's University Hospital, University of Leeds, Leeds, United Kingdom; Section of Genetics, School of Medicine, St James's University Hospital, University of Leeds, Leeds, United Kingdom
| | - Tim D Holmes
- Leeds Institute of Cancer and Pathology, School of Medicine, St James's University Hospital, University of Leeds, Leeds, United Kingdom; Center for Infectious Medicine, Karolinska University Hospital, Stockholm, Sweden
| | - Nikita Gamper
- School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
| | - Walid El-Sayed
- School of Dentistry, University of Leeds, Leeds, United Kingdom; Oral Biology Department, Dental Collage, Gulf Medical University, Ajman, United Arab Emirates
| | - Nishani T Hettiarachchi
- Division of Cardiovascular and Diabetes Research, School of Medicine, University of Leeds, Leeds, United Kingdom
| | - Mushtaq Ahmed
- Clinical Genetics, Leeds Teaching Hospitals NHS Trust, Chapel Allerton Hospital, Leeds, United Kingdom
| | - Graham P Cook
- Leeds Institute of Cancer and Pathology, School of Medicine, St James's University Hospital, University of Leeds, Leeds, United Kingdom
| | - Clare V Logan
- Section of Genetics, School of Medicine, St James's University Hospital, University of Leeds, Leeds, United Kingdom
| | - Colin A Johnson
- Section of Ophthalmology and Neuroscience, School of Medicine, St James's University Hospital, University of Leeds, Leeds, United Kingdom
| | - Shelagh Joss
- Clinical Genetics, Southern General Hospital, Glasgow, United Kingdom
| | - Chris Peers
- Division of Cardiovascular and Diabetes Research, School of Medicine, University of Leeds, Leeds, United Kingdom
| | - Katrina Prescott
- Clinical Genetics, Leeds Teaching Hospitals NHS Trust, Chapel Allerton Hospital, Leeds, United Kingdom
| | - Sinisa Savic
- Department of Clinical Immunology and Allergy, Leeds Teaching Hospitals NHS Trust, St James's University Hospital, University of Leeds, Leeds, United Kingdom
| | - Chris F Inglehearn
- Section of Ophthalmology and Neuroscience, School of Medicine, St James's University Hospital, University of Leeds, Leeds, United Kingdom
| | - Alan J Mighell
- Section of Ophthalmology and Neuroscience, School of Medicine, St James's University Hospital, University of Leeds, Leeds, United Kingdom; School of Dentistry, University of Leeds, Leeds, United Kingdom.
| |
Collapse
|
22
|
Poulter JA, Smith CEL, Murrillo G, Silva S, Feather S, Howell M, Crinnion L, Bonthron DT, Carr IM, Watson CM, Inglehearn CF, Mighell AJ. A distinctive oral phenotype points to FAM20A mutations not identified by Sanger sequencing. Mol Genet Genomic Med 2015; 3:543-9. [PMID: 26740946 PMCID: PMC4694127 DOI: 10.1002/mgg3.164] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Revised: 06/10/2015] [Accepted: 06/11/2015] [Indexed: 11/25/2022] Open
Abstract
Biallelic FAM20A mutations cause two conditions where Amelogenesis Imperfecta (AI) is the presenting feature: Amelogenesis Imperfecta and Gingival Fibromatosis Syndrome; and Enamel Renal Syndrome. A distinctive oral phenotype is shared in both conditions. On Sanger sequencing of FAM20A in cases with that phenotype, we identified two probands with single, likely pathogenic heterozygous mutations. Given the recessive inheritance pattern seen in all previous FAM20A mutation‐positive families and the potential for renal disease, further screening was carried out to look for a second pathogenic allele. Reverse transcriptase‐PCR on cDNA was used to determine transcript levels. CNVseq was used to screen for genomic insertions and deletions. In one family, FAM20A cDNA screening revealed only a single mutated FAM20A allele with the wild‐type allele not transcribed. In the second family, CNV detection by whole genome sequencing (CNVseq) revealed a heterozygous 54.7 kb duplication encompassing exons 1 to 4 of FAM20A. This study confirms the link between biallelic FAM20A mutations and the characteristic oral phenotype. It highlights for the first time examples of FAM20A mutations missed by the most commonly used mutation screening techniques. This information informed renal assessment and ongoing clinical care.
Collapse
Affiliation(s)
- James A Poulter
- Section of Ophthalmology and Neuroscience University of Leeds Leeds United Kingdom
| | - Claire E L Smith
- Section of Ophthalmology and Neuroscience University of Leeds Leeds United Kingdom
| | - Gina Murrillo
- School of Dentistry University of Costa Rica San Pedro Costa Rica
| | - Sandra Silva
- Biology Molecular Cellular Centre (CBCM) University of Costa Rica San Pedro Costa Rica
| | - Sally Feather
- Paediatric Nephrology Leeds Teaching Hospitals NHS Trust Leeds United Kingdom
| | - Marianella Howell
- Paediatric Nephrology National Children's Hospital San Jose Costa Rica
| | - Laura Crinnion
- Yorkshire Regional Genetics ServiceLeeds Teaching Hospitals NHS TrustLeedsUnited Kingdom; Section of GeneticsSchool of MedicineUniversity of LeedsLeedsUnited Kingdom
| | - David T Bonthron
- Yorkshire Regional Genetics ServiceLeeds Teaching Hospitals NHS TrustLeedsUnited Kingdom; Section of GeneticsSchool of MedicineUniversity of LeedsLeedsUnited Kingdom
| | - Ian M Carr
- Section of Genetics School of Medicine University of Leeds Leeds United Kingdom
| | - Christopher M Watson
- Yorkshire Regional Genetics ServiceLeeds Teaching Hospitals NHS TrustLeedsUnited Kingdom; Section of GeneticsSchool of MedicineUniversity of LeedsLeedsUnited Kingdom
| | - Chris F Inglehearn
- Section of Ophthalmology and Neuroscience University of Leeds Leeds United Kingdom
| | - Alan J Mighell
- Section of Ophthalmology and NeuroscienceUniversity of LeedsLeedsUnited Kingdom; Department of Oral MedicineSchool of DentistryUniversity of LeedsLeedsUnited Kingdom
| |
Collapse
|
23
|
Ratbi I, Falkenberg KD, Sommen M, Al-Sheqaih N, Guaoua S, Vandeweyer G, Urquhart JE, Chandler KE, Williams SG, Roberts NA, El Alloussi M, Black GC, Ferdinandusse S, Ramdi H, Heimler A, Fryer A, Lynch SA, Cooper N, Ong KR, Smith CEL, Inglehearn CF, Mighell AJ, Elcock C, Poulter JA, Tischkowitz M, Davies SJ, Sefiani A, Mironov AA, Newman WG, Waterham HR, Van Camp G. Heimler Syndrome Is Caused by Hypomorphic Mutations in the Peroxisome-Biogenesis Genes PEX1 and PEX6. Am J Hum Genet 2015; 97:535-45. [PMID: 26387595 PMCID: PMC4596894 DOI: 10.1016/j.ajhg.2015.08.011] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Accepted: 08/21/2015] [Indexed: 11/17/2022] Open
Abstract
Heimler syndrome (HS) is a rare recessive disorder characterized by sensorineural hearing loss (SNHL), amelogenesis imperfecta, nail abnormalities, and occasional or late-onset retinal pigmentation. We ascertained eight families affected by HS and, by using a whole-exome sequencing approach, identified biallelic mutations in PEX1 or PEX6 in six of them. Loss-of-function mutations in both genes are known causes of a spectrum of autosomal-recessive peroxisome-biogenesis disorders (PBDs), including Zellweger syndrome. PBDs are characterized by leukodystrophy, hypotonia, SNHL, retinopathy, and skeletal, craniofacial, and liver abnormalities. We demonstrate that each HS-affected family has at least one hypomorphic allele that results in extremely mild peroxisomal dysfunction. Although individuals with HS share some subtle clinical features found in PBDs, the diagnosis was not suggested by routine blood and skin fibroblast analyses used to detect PBDs. In conclusion, our findings define HS as a mild PBD, expanding the pleiotropy of mutations in PEX1 and PEX6.
Collapse
Affiliation(s)
- Ilham Ratbi
- Centre de Génomique Humaine, Faculté de Médecine et de Pharmacie, Université Mohammed V, 10100 Rabat, Morocco
| | - Kim D Falkenberg
- Laboratory Genetic Metabolic Diseases, Academic Medical Center, University of Amsterdam, Amsterdam 1105 AZ, the Netherlands
| | - Manou Sommen
- Department of Medical Genetics, University of Antwerp, Antwerp 2610, Belgium
| | - Nada Al-Sheqaih
- Manchester Centre for Genomic Medicine, St. Mary's Hospital, Manchester Academic Health Sciences Centre, Manchester M13 9WL, UK; Manchester Centre for Genomic Medicine, Institute of Human Development, University of Manchester, Manchester M13 9WL, UK
| | - Soukaina Guaoua
- Centre de Génomique Humaine, Faculté de Médecine et de Pharmacie, Université Mohammed V, 10100 Rabat, Morocco
| | - Geert Vandeweyer
- Department of Medical Genetics, University of Antwerp, Antwerp 2610, Belgium
| | - Jill E Urquhart
- Manchester Centre for Genomic Medicine, St. Mary's Hospital, Manchester Academic Health Sciences Centre, Manchester M13 9WL, UK; Manchester Centre for Genomic Medicine, Institute of Human Development, University of Manchester, Manchester M13 9WL, UK
| | - Kate E Chandler
- Manchester Centre for Genomic Medicine, St. Mary's Hospital, Manchester Academic Health Sciences Centre, Manchester M13 9WL, UK; Manchester Centre for Genomic Medicine, Institute of Human Development, University of Manchester, Manchester M13 9WL, UK
| | - Simon G Williams
- Manchester Centre for Genomic Medicine, St. Mary's Hospital, Manchester Academic Health Sciences Centre, Manchester M13 9WL, UK; Manchester Centre for Genomic Medicine, Institute of Human Development, University of Manchester, Manchester M13 9WL, UK
| | - Neil A Roberts
- Manchester Centre for Genomic Medicine, St. Mary's Hospital, Manchester Academic Health Sciences Centre, Manchester M13 9WL, UK; Manchester Centre for Genomic Medicine, Institute of Human Development, University of Manchester, Manchester M13 9WL, UK
| | - Mustapha El Alloussi
- Département de Pédodontie-Prévention, Faculté de Médecine Dentaire, Université Mohammed V, BP 6212 Madinat Al Irfane, 10100 Rabat, Morocco; Service d'Odontologie, Hôpital Militaire d'Instruction Mohamed V, Avenue des Far, Hay Riad, 10100 Rabat, Morocco
| | - Graeme C Black
- Manchester Centre for Genomic Medicine, St. Mary's Hospital, Manchester Academic Health Sciences Centre, Manchester M13 9WL, UK; Manchester Centre for Genomic Medicine, Institute of Human Development, University of Manchester, Manchester M13 9WL, UK
| | - Sacha Ferdinandusse
- Laboratory Genetic Metabolic Diseases, Academic Medical Center, University of Amsterdam, Amsterdam 1105 AZ, the Netherlands
| | - Hind Ramdi
- Département de Pédodontie-Prévention, Faculté de Médecine Dentaire, Université Mohammed V, BP 6212 Madinat Al Irfane, 10100 Rabat, Morocco
| | - Audrey Heimler
- Division of Human Genetics, Schneider Children's Hospital of Long Island Jewish Medical Center, New Hyde Park, NY 11042, USA
| | - Alan Fryer
- Department of Clinical Genetics, Liverpool Women's NHS Foundation Trust, Liverpool L8 7SS, UK
| | - Sally-Ann Lynch
- National Centre for Medical Genetics, Our Lady's Children's Hospital, Crumlin, Dublin 12, Ireland; Department of Genetics, Children's University Hospital, Dublin 12, Ireland
| | - Nicola Cooper
- West Midlands Regional Genetics Service, Birmingham Women's Hospital NHS Trust, Birmingham B15 2TG, UK
| | - Kai Ren Ong
- West Midlands Regional Genetics Service, Birmingham Women's Hospital NHS Trust, Birmingham B15 2TG, UK
| | - Claire E L Smith
- Leeds Institute of Biomedical and Clinical Sciences, St. James's University Hospital, University of Leeds, Leeds LS9 7TF, UK
| | - Christopher F Inglehearn
- Leeds Institute of Biomedical and Clinical Sciences, St. James's University Hospital, University of Leeds, Leeds LS9 7TF, UK
| | - Alan J Mighell
- Leeds Institute of Biomedical and Clinical Sciences, St. James's University Hospital, University of Leeds, Leeds LS9 7TF, UK; School of Dentistry, University of Leeds, Leeds LS2 9JT, UK
| | - Claire Elcock
- Academic Unit of Oral Health and Development, School of Clinical Dentistry, University of Sheffield, S10 2TA, UK
| | - James A Poulter
- Leeds Institute of Biomedical and Clinical Sciences, St. James's University Hospital, University of Leeds, Leeds LS9 7TF, UK
| | - Marc Tischkowitz
- Department of Medical Genetics and National Institute for Health Research Cambridge Biomedical Research Centre, University of Cambridge, Cambridge CB2 0QQ, UK; Department of Clinical Genetics, East Anglian Regional Genetics Service, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Sally J Davies
- Institute of Medical Genetics, University Hospital of Wales, Cardiff CF14 4XW, UK
| | - Abdelaziz Sefiani
- Centre de Génomique Humaine, Faculté de Médecine et de Pharmacie, Université Mohammed V, 10100 Rabat, Morocco; Département de Génétique Médicale, Institut National d'Hygiène, BP 769 Agdal, 10090 Rabat, Morocco
| | | | - William G Newman
- Manchester Centre for Genomic Medicine, St. Mary's Hospital, Manchester Academic Health Sciences Centre, Manchester M13 9WL, UK; Manchester Centre for Genomic Medicine, Institute of Human Development, University of Manchester, Manchester M13 9WL, UK
| | - Hans R Waterham
- Laboratory Genetic Metabolic Diseases, Academic Medical Center, University of Amsterdam, Amsterdam 1105 AZ, the Netherlands.
| | - Guy Van Camp
- Department of Medical Genetics, University of Antwerp, Antwerp 2610, Belgium.
| |
Collapse
|
24
|
Cottom H, Mighell AJ, High A, Bateman AC. Are plasma cell-rich inflammatory conditions of the oral mucosa manifestations of IgG4-related disease? J Clin Pathol 2015; 68:802-7. [DOI: 10.1136/jclinpath-2014-202814] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 05/24/2015] [Indexed: 12/24/2022]
Abstract
AimThe aim of this study was to characterise plasma cell infiltrates, in terms of IgG4 positivity, in specific and non-specific plasma cell-rich chronic inflammatory conditions of the oral mucosa. Exploring the possibility that specific plasma cell-rich oral inflammatory conditions have association with or represent an oral manifestation of immunoglobulin G4-related disease (IgG4-RD).MethodsTen patients with plasma cell-rich chronic inflammatory conditions of the oral mucosa were identified (seven—plasma cell mucositis and three—non-specific diffuse oral mucosal inflammation with ulceration). For each patient, the clinical record and H&E-stained sections were reviewed. Immunohistochemistry for IgG and IgG4 antibodies was performed on sections from the corresponding paraffin block, permitting calculation of the mean number of IgG4+ plasma cells per high-power field (HPF) and the IgG4+/IgG+ plasma cell ratio.ResultsIn all the cases, only one histological hallmark of IgG4-RD—a dense lymphoplasmacytic infiltrate—was seen. Review of the medical histories did not reveal any features representing other manifestations of IgG4-RD. The number of IgG4+ plasma cells exceeded 100 per HPF in half of the cases. Only two cases had an IgG4+/IgG+ plasma cell ratio of >40%; both of which were in the non-specific oral inflammatory group.ConclusionsOur study suggests that plasma cell mucositis does not meet microscopic criteria for IgG4-RD. It importantly reinforces the opinion that IgG4+ plasma cells are major components of chronic inflammation in the oral cavity and the pertinence of correct contextual interpretation of histopathological features with clinical findings.
Collapse
|
25
|
Acevedo AC, Poulter JA, Alves PG, de Lima CL, Castro LC, Yamaguti PM, Paula LM, Parry DA, Logan CV, Smith CEL, Johnson CA, Inglehearn CF, Mighell AJ. Variability of systemic and oro-dental phenotype in two families with non-lethal Raine syndrome with FAM20C mutations. BMC Med Genet 2015; 16:8. [PMID: 25928877 PMCID: PMC4422040 DOI: 10.1186/s12881-015-0154-5] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Accepted: 02/06/2015] [Indexed: 12/30/2022]
Abstract
Background Raine syndrome (RS) is a rare autosomal recessive bone dysplasia typified by osteosclerosis and dysmorphic facies due to FAM20C mutations. Initially reported as lethal in infancy, survival is possible into adulthood. We describe the molecular analysis and clinical phenotypes of five individuals from two consanguineous Brazilian families with attenuated Raine Syndrome with previously unreported features. Methods The medical and dental clinical records were reviewed. Extracted deciduous and permanent teeth as well as oral soft tissues were analysed. Whole exome sequencing was undertaken and FAM20C cDNA sequenced in family 1. Results Family 1 included 3 siblings with hypoplastic Amelogenesis Imperfecta (AI) (inherited abnormal dental enamel formation). Mild facial dysmorphism was noted in the absence of other obvious skeletal or growth abnormalities. A mild hypophosphataemia and soft tissue ectopic mineralization were present. A homozygous FAM20C donor splice site mutation (c.784 + 5 g > c) was identified which led to abnormal cDNA sequence. Family 2 included 2 siblings with hypoplastic AI and tooth dentine abnormalities as part of a more obvious syndrome with facial dysmorphism. There was hypophosphataemia, soft tissue ectopic mineralization, but no osteosclerosis. A homozygous missense mutation in FAM20C (c.1487C > T; p.P496L) was identified. Conclusions The clinical phenotype of non-lethal Raine Syndrome is more variable, including between affected siblings, than previously described and an adverse impact on bone growth and health may not be a prominent feature. By contrast, a profound failure of dental enamel formation leading to a distinctive hypoplastic AI in all teeth should alert clinicians to the possibility of FAM20C mutations. Electronic supplementary material The online version of this article (doi:10.1186/s12881-015-0154-5) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Ana Carolina Acevedo
- Oral Care Center for Inherited Diseases, University Hospital of Brasilia, Department of Dentistry, Health Sciences School, University of Brasilia, Brasilia, Brazil.
| | - James A Poulter
- Section of Ophthalmology and Neuroscience, University of Leeds, Leeds, UK.
| | - Priscila Gomes Alves
- Oral Care Center for Inherited Diseases, University Hospital of Brasilia, Department of Dentistry, Health Sciences School, University of Brasilia, Brasilia, Brazil.
| | - Caroline Lourenço de Lima
- Oral Care Center for Inherited Diseases, University Hospital of Brasilia, Department of Dentistry, Health Sciences School, University of Brasilia, Brasilia, Brazil.
| | - Luiz Claudio Castro
- Department of Pediatrics, School of Medicine, University of Brasilia, Brasilia, Brazil.
| | - Paulo Marcio Yamaguti
- Oral Care Center for Inherited Diseases, University Hospital of Brasilia, Department of Dentistry, Health Sciences School, University of Brasilia, Brasilia, Brazil.
| | - Lilian M Paula
- Oral Care Center for Inherited Diseases, University Hospital of Brasilia, Department of Dentistry, Health Sciences School, University of Brasilia, Brasilia, Brazil.
| | - David A Parry
- Section of Genetics, School of Medicine, University of Leeds, Leeds, UK.
| | - Clare V Logan
- Section of Ophthalmology and Neuroscience, University of Leeds, Leeds, UK.
| | - Claire E L Smith
- Section of Ophthalmology and Neuroscience, University of Leeds, Leeds, UK.
| | - Colin A Johnson
- Section of Ophthalmology and Neuroscience, University of Leeds, Leeds, UK.
| | - Chris F Inglehearn
- Section of Ophthalmology and Neuroscience, University of Leeds, Leeds, UK.
| | - Alan J Mighell
- Section of Ophthalmology and Neuroscience, University of Leeds, Leeds, UK. .,Department of Oral Medicine, School of Dentistry, University of Leeds, Leeds, UK.
| |
Collapse
|
26
|
de la Dure-Molla M, Quentric M, Yamaguti PM, Acevedo AC, Mighell AJ, Vikkula M, Huckert M, Berdal A, Bloch-Zupan A. Pathognomonic oral profile of Enamel Renal Syndrome (ERS) caused by recessive FAM20A mutations. Orphanet J Rare Dis 2014; 9:84. [PMID: 24927635 PMCID: PMC4071802 DOI: 10.1186/1750-1172-9-84] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Accepted: 05/26/2014] [Indexed: 12/28/2022] Open
Abstract
Amelogenesis imperfecta (AI) is a genetically and clinically heterogeneous group of inherited dental enamel defects. Commonly described as an isolated trait, it may be observed concomitantly with other orodental and/or systemic features such as nephrocalcinosis in Enamel Renal Syndrome (ERS, MIM#204690), or gingival hyperplasia in Amelogenesis Imperfecta and Gingival Fibromatosis Syndrome (AIGFS, MIM#614253). Patients affected by ERS/AIGFS present a distinctive orodental phenotype consisting of generalized hypoplastic AI affecting both the primary and permanent dentition, delayed tooth eruption, pulp stones, hyperplastic dental follicles, and gingival hyperplasia with variable severity and calcified nodules. Renal exam reveals a nephrocalcinosis which is asymptomatic in children affected by ERS. FAM20A recessive mutations are responsible for both syndromes. We suggest that AIGFS and ERS are in fact descriptions of the same syndrome, but that the kidney phenotype has not always been investigated fully in AIGFS. The aim of this review is to highlight the distinctive and specific orodental features of patients with recessive mutations in FAM20A. We propose ERS to be the preferred term for all the phenotypes arising from recessive FAM20A mutations. A differential diagnosis has to be made with other forms of AI, isolated or syndromic, where only a subset of the clinical signs may be shared. When ERS is suspected, the patient should be assessed by a dentist, nephrologist and clinical geneticist. Confirmed cases require long-term follow-up. Management of the orodental aspects can be extremely challenging and requires the input of multi-disciplinary specialized dental team, especially when there are multiple unerupted teeth.
Collapse
Affiliation(s)
- Muriel de la Dure-Molla
- Laboratory of Molecular Oral Pathophysiology, INSERM UMRS 1138, Cordeliers Research Center, Paris, France.
| | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Poulter JA, Murillo G, Brookes SJ, Smith CEL, Parry DA, Silva S, Kirkham J, Inglehearn CF, Mighell AJ. Deletion of ameloblastin exon 6 is associated with amelogenesis imperfecta. Hum Mol Genet 2014; 23:5317-24. [PMID: 24858907 PMCID: PMC4168819 DOI: 10.1093/hmg/ddu247] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Amelogenesis imperfecta (AI) describes a heterogeneous group of inherited dental enamel defects reflecting failure of normal amelogenesis. Ameloblastin (AMBN) is the second most abundant enamel matrix protein expressed during amelogenesis. The pivotal role of AMBN in amelogenesis has been confirmed experimentally using mouse models. However, no AMBN mutations have been associated with human AI. Using autozygosity mapping and exome sequencing, we identified genomic deletion of AMBN exon 6 in a second cousin consanguineous family with three of the six children having hypoplastic AI. The genomic deletion corresponds to an in-frame deletion of 79 amino acids, shortening the protein from 447 to 368 residues. Exfoliated primary teeth (unmatched to genotype) were available from family members. The most severely affected had thin, aprismatic enamel (similar to that reported in mice homozygous for Ambn lacking exons 5 and 6). Other teeth exhibited thicker but largely aprismatic enamel. One tooth had apparently normal enamel. It has been suggested that AMBN may function in bone development. No clinically obvious bone or other co-segregating health problems were identified in the family investigated. This study confirms for the first time that AMBN mutations cause non-syndromic human AI and that mouse models with disrupted Ambn function are valid.
Collapse
Affiliation(s)
- James A Poulter
- Leeds Institute of Biomedical and Clinical Sciences, St James's University Hospital, University of Leeds, Leeds LS9 7TF, UK
| | | | | | - Claire E L Smith
- Leeds Institute of Biomedical and Clinical Sciences, St James's University Hospital, University of Leeds, Leeds LS9 7TF, UK
| | - David A Parry
- Leeds Institute of Biomedical and Clinical Sciences, St James's University Hospital, University of Leeds, Leeds LS9 7TF, UK
| | - Sandra Silva
- Biology, Molecular Cellular Centre (CBCM), University of Costa Rica, San Pedro, Costa Rica
| | | | - Chris F Inglehearn
- Leeds Institute of Biomedical and Clinical Sciences, St James's University Hospital, University of Leeds, Leeds LS9 7TF, UK
| | - Alan J Mighell
- Leeds Institute of Biomedical and Clinical Sciences, St James's University Hospital, University of Leeds, Leeds LS9 7TF, UK School of Dentistry, University of Leeds, Leeds LS2 9LU, UK
| |
Collapse
|
28
|
Poulter JA, El-Sayed W, Shore RC, Kirkham J, Inglehearn CF, Mighell AJ. Whole-exome sequencing, without prior linkage, identifies a mutation in LAMB3 as a cause of dominant hypoplastic amelogenesis imperfecta. Eur J Hum Genet 2014; 22:132-5. [PMID: 23632796 PMCID: PMC3865405 DOI: 10.1038/ejhg.2013.76] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Accepted: 03/24/2013] [Indexed: 01/13/2023] Open
Abstract
The conventional approach to identifying the defective gene in a family with an inherited disease is to find the disease locus through family studies. However, the rapid development and decreasing cost of next generation sequencing facilitates a more direct approach. Here, we report the identification of a frameshift mutation in LAMB3 as a cause of dominant hypoplastic amelogenesis imperfecta (AI). Whole-exome sequencing of three affected family members and subsequent filtering of shared variants, without prior genetic linkage, sufficed to identify the pathogenic variant. Simultaneous analysis of multiple family members confirms segregation, enhancing the power to filter the genetic variation found and leading to rapid identification of the pathogenic variant. LAMB3 encodes a subunit of Laminin-5, one of a family of basement membrane proteins with essential functions in cell growth, movement and adhesion. Homozygous LAMB3 mutations cause junctional epidermolysis bullosa (JEB) and enamel defects are seen in JEB cases. However, to our knowledge, this is the first report of dominant AI due to a LAMB3 mutation in the absence of JEB.
Collapse
Affiliation(s)
- James A Poulter
- Section of Ophthalmology and Neuroscience, Leeds Institute of Molecular Medicine, University of Leeds, Leeds, UK
| | - Walid El-Sayed
- Section of Ophthalmology and Neuroscience, Leeds Institute of Molecular Medicine, University of Leeds, Leeds, UK
- Department of Oral Biology, Dental School, Suez Canal University, Ismailia, Egypt
- Department of Oral Medicine, Leeds Dental Institute, University of Leeds, Leeds, UK
| | - Roger C Shore
- Department of Oral Biology, Leeds Dental Institute, University of Leeds, Leeds, UK
| | - Jennifer Kirkham
- Department of Oral Biology, Leeds Dental Institute, University of Leeds, Leeds, UK
| | - Chris F Inglehearn
- Section of Ophthalmology and Neuroscience, Leeds Institute of Molecular Medicine, University of Leeds, Leeds, UK
| | - Alan J Mighell
- Section of Ophthalmology and Neuroscience, Leeds Institute of Molecular Medicine, University of Leeds, Leeds, UK
- Department of Oral Medicine, Leeds Dental Institute, University of Leeds, Leeds, UK
| |
Collapse
|
29
|
Poulter JA, Brookes SJ, Shore RC, Smith CEL, Abi Farraj L, Kirkham J, Inglehearn CF, Mighell AJ. A missense mutation in ITGB6 causes pitted hypomineralized amelogenesis imperfecta. Hum Mol Genet 2013; 23:2189-97. [PMID: 24319098 PMCID: PMC3959822 DOI: 10.1093/hmg/ddt616] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We identified a family in which pitted hypomineralized amelogenesis imperfecta (AI) with premature enamel failure segregated in an autosomal recessive fashion. Whole-exome sequencing revealed a missense mutation (c.586C>A, p.P196T) in the I-domain of integrin-β6 (ITGB6), which is consistently predicted to be pathogenic by all available programmes and is the only variant that segregates with the disease phenotype. Furthermore, a recent study revealed that mice lacking a functional allele of Itgb6 display a hypomaturation AI phenotype. Phenotypic characterization of affected human teeth in this study showed areas of abnormal prismatic organization, areas of low mineral density and severe abnormal surface pitting in the tooth's coronal portion. We suggest that the pathogenesis of this form of AI may be due to ineffective ligand binding of ITGB6 resulting in either compromised cell-matrix interaction or compromised ITGB6 activation of transforming growth factor-β (TGF-β) impacting indirectly on ameloblast-ameloblast interactions and proteolytic processing of extracellular matrix proteins via MMP20. This study adds to the list of genes mutated in AI and further highlights the importance of cell-matrix interactions during enamel formation.
Collapse
Affiliation(s)
- James A Poulter
- Leeds Institutes of Molecular Medicine, University of Leeds, Leeds LS9 7TF, UK
| | | | | | | | | | | | | | | |
Collapse
|
30
|
Mighell AJ, Atkin PA, Webster K, Thomas SJ, McCreary CE, Healy CM, Gibson J, Crighton AJ, Dawson LJ, Smalley JO, Allan RB, Oliver RJ, Pattrick MG, Pemberton MN, Theaker ED, Poate TW, Buchanan JAG, Greenwood M, Bee D, Yates JM, Crean SJ, Napier SS. Clinical medical sciences for undergraduate dental students in the United Kingdom and Ireland - a curriculum. Eur J Dent Educ 2011; 15:179-188. [PMID: 21762323 DOI: 10.1111/j.1600-0579.2010.00654.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The technical aspects of dentistry need to be practised with insight into the spectrum of human diseases and illnesses and how these impact upon individuals and society. Application of this insight is critical to decision-making related to the planning and delivery of safe and appropriate patient-centred healthcare tailored to the needs of the individual. Provision for the necessary training is included in undergraduate programmes, but in the United Kingdom and Ireland there is considerable variation between centres without common outcomes. In 2009 representatives from 17 undergraduate dental schools in the United Kingdom and Ireland agreed to move towards a common, shared approach to meet their own immediate needs and that might also be of value to others in keeping with the Bologna Process. To provide a clear identity the term 'Clinical Medical Sciences in Dentistry' was agreed in preference to other names such as 'Human Disease' or 'Medicine and Surgery'. The group was challenged to define consensus outcomes. Contemporary dental education documents informed, but did not drive the process. The consensus curriculum for undergraduate Clinical Medical Sciences in Dentistry teaching agreed by the participating centres is reported. Many of the issues are generic and it includes elements that are likely to be applicable to others. This document will act as a focus for a more unified approach to the outcomes required by graduates of the participating centres and act as a catalyst for future developments that ultimately aim to enhance the quality of patient care.
Collapse
Affiliation(s)
- A J Mighell
- The University of Leeds, Leeds Dental Institute, Leeds, UK.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Kerr AR, Warnakulasuriya S, Mighell AJ, Dietrich T, Nasser M, Rimal J, Jalil A, Bornstein MM, Nagao T, Fortune F, Hazarey VH, Reichart PA, Silverman S, Johnson NW. A systematic review of medical interventions for oral submucous fibrosis and future research opportunities. Oral Dis 2011; 17 Suppl 1:42-57. [DOI: 10.1111/j.1601-0825.2011.01791.x] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
|
32
|
El-Sayed W, Shore RC, Parry DA, Inglehearn CF, Mighell AJ. Hypomaturation amelogenesis imperfecta due to WDR72 mutations: a novel mutation and ultrastructural analyses of deciduous teeth. Cells Tissues Organs 2010; 194:60-6. [PMID: 21196691 PMCID: PMC3128158 DOI: 10.1159/000322036] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/14/2010] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Mutations in WDR72 have been identified in autosomal recessive hypomaturation amelogenesis imperfecta (AI). OBJECTIVE to describe a novel WDR72 mutation and report the ultrastructural enamel phenotype associated with a different WDR72 mutation. METHODS A family segregating autosomal recessive hypomaturation AI was recruited, genomic DNA obtained and WDR72 sequenced. Four deciduous teeth from one individual with a previously published WDR72 mutation, extracted as part of clinical care, were subjected to scanning electron microscopy, energy-dispersive X-ray analysis and transverse microradiography. RESULTS A novel homozygous nonsense mutation, R897X, was identified in WDR72 in a family originating from Pakistan. Ultrastructural analysis of enamel from the deciduous teeth of an AI patient with the WDR72 mutation S783X revealed energy-dispersive X-ray analysis spectra with normal carbon and nitrogen peaks, excluding retention of enamel matrix protein. However, transverse microradiography values were significantly lower for affected teeth when compared to normal teeth, consistent with reduced mineralisation. On scanning electron microscopy the enamel rod form observed was normal, yet with inter-rod enamel more prominent than in controls. This appearance was unaltered following incubation with either α-chymotrypsin or lipase. CONCLUSIONS The novel WDR72 mutation described brings the total reported WDR72 mutations to four. Analyses of deciduous tooth enamel in an individual with a homozygous WDR72 mutation identified changes consistent with a late failure of enamel maturation without retention of matrix proteins. The mechanisms by which intracellular WDR72 influences enamel maturation remain unknown.
Collapse
Affiliation(s)
- W El-Sayed
- Leeds Dental Institute, University of Leeds, Leeds, UK
| | | | | | | | | |
Collapse
|
33
|
Abstract
The British Society for Oral Medicine (www.bsom.org.uk) defines oral medicine as 'the specialty of dentistry concerned with the oral health care of patients with chronic recurrent and medically related disorders of the oral and maxillofacial region, and with their diagnosis and non-surgical management.'
Collapse
Affiliation(s)
- Anne M Hegarty
- Oral Medicine, Charles Clifford Dental Hospital, Sheffield S10 2SZ
| | | |
Collapse
|
34
|
El-Sayed W, Parry DA, Shore RC, Ahmed M, Jafri H, Rashid Y, Al-Bahlani S, Al Harasi S, Kirkham J, Inglehearn CF, Mighell AJ. Mutations in the beta propeller WDR72 cause autosomal-recessive hypomaturation amelogenesis imperfecta. Am J Hum Genet 2009; 85:699-705. [PMID: 19853237 PMCID: PMC2775821 DOI: 10.1016/j.ajhg.2009.09.014] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2009] [Revised: 09/22/2009] [Accepted: 09/25/2009] [Indexed: 11/26/2022] Open
Abstract
Healthy dental enamel is the hardest and most highly mineralized human tissue. Though acellular, nonvital, and without capacity for turnover or repair, it can nevertheless last a lifetime. Amelogenesis imperfecta (AI) is a collective term for failure of normal enamel development, covering diverse clinical phenotypes that typically show Mendelian inheritance patterns. One subset, known as hypomaturation AI, is characterised by near-normal volumes of organic enamel matrix but with weak, creamy-brown opaque enamel that fails prematurely after tooth eruption. Mutations in genes critical to enamel matrix formation have been documented, but current understanding of other key events in enamel biomineralization is limited. We investigated autosomal-recessive hypomaturation AI in a consanguineous Pakistani family. A whole-genome SNP autozygosity screen identified a locus on chromosome 15q21.3. Sequencing candidate genes revealed a point mutation in the poorly characterized WDR72 gene. Screening of WDR72 in a panel of nine additional hypomaturation AI families revealed the same mutation in a second, apparently unrelated, Pakistani family and two further nonsense mutations in Omani families. Immunohistochemistry confirmed intracellular localization in maturation-stage ameloblasts. WDR72 function is unknown, but as a putative β propeller is expected to be a scaffold for protein-protein interactions. The nearest homolog, WDR7, is involved in vesicle mobilization and Ca2+-dependent exocytosis at synapses. Vesicle trafficking is important in maturation-stage ameloblasts with respect to secretion into immature enamel and removal of cleaved enamel matrix proteins via endocytosis. This raises the intriguing possibility that WDR72 is critical to ameloblast vesicle turnover during enamel maturation.
Collapse
|
35
|
El-Sayed W, Shore RC, Parry DA, Inglehearn CF, Mighell AJ. Ultrastructural analyses of deciduous teeth affected by hypocalcified amelogenesis imperfecta from a family with a novel Y458X FAM83H nonsense mutation. Cells Tissues Organs 2009; 191:235-9. [PMID: 20160442 DOI: 10.1159/000252801] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/17/2009] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Nonsense mutations in FAM83H are a recently described underlying cause of autosomal dominant (AD) hypocalcified amelogenesis imperfecta (AI). OBJECTIVE This study aims to report a novel c.1374C>A p.Y458X nonsense mutation and describe the associated ultrastructural phenotype of deciduous teeth. METHODS A family of European origin from the Iberian Peninsula with AD-inherited AI was ascertained. Family members were assessed through clinical examination and supporting investigations. Naturally exfoliated deciduous teeth from 2 siblings were investigated by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and transverse microradiography (TMR). RESULTS On clinical and radiographic investigation the appearances of the affected deciduous and permanent teeth were consistent with hypocalcified AI with small focal areas of more normal looking enamel. DNA sequencing identified a novel c.1374C>A p.Y458X FAM83H nonsense mutation in affected, but not in either unaffected family members or unrelated controls. Exfoliated teeth were characterised by substantial post-eruptive enamel loss on gross examination. Irregular, poor quality enamel prisms were observed on SEM. These were coated in amorphous material. TMR and EDX confirmed reduced mineral and increased organic content in enamel, respectively. CONCLUSIONS FAM83H nonsense mutations have recently been recognised as a cause of AD hypocalcified AI. We report a novel nonsense FAM83H mutation and describe the associated preliminary ultrastructural phenotype in deciduous teeth. This is characterised by poorly formed enamel rods with inappropriate retention of amorphous material, which is likely to represent retained organic matrix that contributes to the overall hypomineralised phenotype.
Collapse
Affiliation(s)
- W El-Sayed
- Leeds Dental Institute, University of Leeds, UK
| | | | | | | | | |
Collapse
|
36
|
Bransfield KL, Askham JM, Leek JP, Robinson PA, Mighell AJ. Phenotypic changes associated with DYNACTIN-2 (DCTN2) over expression characterise SJSA-1 osteosarcoma cells. Mol Carcinog 2006; 45:157-63. [PMID: 16369996 DOI: 10.1002/mc.20151] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
DYNACTIN-2 (DCTN2) localises to chromosome 12q13-q15, a region prone to stable amplification in several cancers. Transient DCTN2 overexpression has a significant impact on cellular phenotype primarily due to disruption of the DYNEIN-dynactin motor. Changes reported include alterations of microtubule-directed movement of molecular (e.g. TP53) and organelle (e.g. Golgi) cargoes towards the nucleus, centrosome biology, cellular movement and mitosis with a potential predisposition to mitotic block and polyploidy. These changes would be expected to be of relevance to carcinogenesis. To investigate this, we report the first study of DCTN2 genomic amplification and sustained DCTN2 overexpression in cancer cells. QFMPCR was employed to characterise the extent of chromosome 12q13-q15 amplicons in SJSA-1, SJRH30, U373MG and CCF-STTG1 cancer cells. DCTN2 amplification was present in SJSA-1, U373MG and SJRH30 cells, yet was incomplete at the 5'-end in SJRH30 cells. Only SJSA-1 cells were characterised by DCTN2 overexpression on Western blot analyses. Microscopy studies distinguished SJSA-1 cells by greater DCTN2 immunofluorescence and diminished centrosome and 58K protein Golgi-marker focus compared to SJRH30 cells. Indirect evidence derived from the published work of others indicated that TP53 transport into the nucleus was unimpaired. Furthermore, we observed that SJSA-1 cells were easy to propagate. In conclusion, persistent DCTN2 overexpression can be tolerated in SJSA-1 cancer cells despite phenotypic abnormalities predicted from transient overexpression studies. This preliminary study does not support a major role for DCTN2 overexpression in carcinogenesis, although further studies would be necessary to confirm this.
Collapse
Affiliation(s)
- Kieran L Bransfield
- Molecular Medicine Unit, The University of Leeds, St. James's University Hospital, Leeds, United Kingdom
| | | | | | | | | |
Collapse
|
37
|
Ponchel F, Toomes C, Bransfield K, Leong FT, Douglas SH, Field SL, Bell SM, Combaret V, Puisieux A, Mighell AJ, Robinson PA, Inglehearn CF, Isaacs JD, Markham AF. Real-time PCR based on SYBR-Green I fluorescence: an alternative to the TaqMan assay for a relative quantification of gene rearrangements, gene amplifications and micro gene deletions. BMC Biotechnol 2003; 3:18. [PMID: 14552656 PMCID: PMC270040 DOI: 10.1186/1472-6750-3-18] [Citation(s) in RCA: 221] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2003] [Accepted: 10/13/2003] [Indexed: 02/08/2023] Open
Abstract
Background Real-time PCR is increasingly being adopted for RNA quantification and genetic analysis. At present the most popular real-time PCR assay is based on the hybridisation of a dual-labelled probe to the PCR product, and the development of a signal by loss of fluorescence quenching as PCR degrades the probe. Though this so-called 'TaqMan' approach has proved easy to optimise in practice, the dual-labelled probes are relatively expensive. Results We have designed a new assay based on SYBR-Green I binding that is quick, reliable, easily optimised and compares well with the published assay. Here we demonstrate its general applicability by measuring copy number in three different genetic contexts; the quantification of a gene rearrangement (T-cell receptor excision circles (TREC) in peripheral blood mononuclear cells); the detection and quantification of GLI, MYC-C and MYC-N gene amplification in cell lines and cancer biopsies; and detection of deletions in the OPA1 gene in dominant optic atrophy. Conclusion Our assay has important clinical applications, providing accurate diagnostic results in less time, from less biopsy material and at less cost than assays currently employed such as FISH or Southern blotting.
Collapse
Affiliation(s)
| | - Carmel Toomes
- Molecular Medicine Unit, University of Leeds, Leeds, UK
| | | | - Fong T Leong
- Molecular Medicine Unit, University of Leeds, Leeds, UK
| | | | - Sarah L Field
- Molecular Medicine Unit, University of Leeds, Leeds, UK
| | - Sandra M Bell
- Molecular Medicine Unit, University of Leeds, Leeds, UK
| | | | | | | | | | | | - John D Isaacs
- Molecular Medicine Unit, University of Leeds, Leeds, UK
| | | |
Collapse
|
38
|
Adu J, Leong FT, Smith NR, Leek JP, Markham AF, Robinson PA, Mighell AJ. Expression of mOb1, a novel atypical 73 amino acid K50-homeodomain protein, during mouse development. Mech Dev 2002; 119 Suppl 1:S43-7. [PMID: 14516659 DOI: 10.1016/s0925-4773(03)00090-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We report the initial characterization of mOb1 (Odd homeoBox 1), which encodes an atypical 73 amino acid K50-homeodomain protein localised in the cytoplasm and absent from nuclei during mouse development. Conserved orthologues were present in man, rat, cow, pig and chicken, but not in fish, amphibians or invertebrates. Temporo-spatial patterns of mOb1 transcript and mOb1 protein expression were coincident in developing mouse embryos. Cardiac expression was first observed at E8.25 in linear heart tube myocardium and briefly in both horns of the sinus venosus. Myocardial expression peaked at E13.5, where after it diminished and was not detectable above background by adulthood. At no stage was expression observed in endocardium, endocardial cushion tissue, the coronary arteries or great vessels. At E13.5 and E15.5, mOb1 expression broadened to include skeletal muscle, stratified epithelium (upper aerodigestive tract and skin), epithelium of developing airways, vibrissae, midbrain/hindbrain junction, meninges, mesenchymal cellular condensations that preceded cartilage formation and chondrocytes.
Collapse
Affiliation(s)
- Jimi Adu
- Molecular Medicine Unit, Clinical Sciences Building, St. James's University Hospital, The University of Leeds, Leeds, LS9 7TF, UK
| | | | | | | | | | | | | |
Collapse
|
39
|
Adu J, Leong FT, Smith NR, Leek JP, Markham AF, Robinson PA, Mighell AJ. Expression of mOb1, a novel atypical 73 amino acid K50-homeodomain protein, during mouse development. Gene Expr Patterns 2002; 2:39-43. [PMID: 12617835 DOI: 10.1016/s0925-4773(02)00354-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We report the initial characterization of mOb1 (Odd homeoBox 1), which encodes an atypical 73 amino acid K50-homeodomain protein localised in the cytoplasm and absent from nuclei during mouse development. Conserved orthologues were present in man, rat, cow, pig and chicken, but not in fish, amphibians or invertebrates. Temporo-spatial patterns of mOb1 transcript and mOb1 protein expression were coincident in developing mouse embryos. Cardiac expression was first observed at E8.25 in linear heart tube myocardium and briefly in both horns of the sinus venosus. Myocardial expression peaked at E13.5, where after it diminished and was not detectable above background by adulthood. At no stage was expression observed in endocardium, endocardial cushion tissue, the coronary arteries or great vessels. At E13.5 and E15.5, mOb1 expression broadened to include skeletal muscle, stratified epithelium (upper aerodigestive tract and skin), epithelium of developing airways, vibrissae, midbrain/hindbrain junction, meninges, mesenchymal cellular condensations that preceded cartilage formation and chondrocytes.
Collapse
Affiliation(s)
- Jimi Adu
- Molecular Medicine Unit, Clinical Sciences Building, St. James's University Hospital, The University of Leeds, Leeds, LS9 7TF, UK
| | | | | | | | | | | | | |
Collapse
|
40
|
Jackson AP, Eastwood H, Bell SM, Adu J, Toomes C, Carr IM, Roberts E, Hampshire DJ, Crow YJ, Mighell AJ, Karbani G, Jafri H, Rashid Y, Mueller RF, Markham AF, Woods CG. Identification of microcephalin, a protein implicated in determining the size of the human brain. Am J Hum Genet 2002; 71:136-42. [PMID: 12046007 PMCID: PMC419993 DOI: 10.1086/341283] [Citation(s) in RCA: 292] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2002] [Accepted: 04/15/2002] [Indexed: 11/03/2022] Open
Abstract
Primary microcephaly (MIM 251200) is an autosomal recessive neurodevelopmental condition in which there is a global reduction in cerebral cortex volume, to a size comparable with that of early hominids. We previously mapped the MCPH1 locus, for primary microcephaly, to chromosome 8p23, and here we report that a gene within this interval, encoding a BRCA1 C-terminal domain-containing protein, is mutated in MCPH1 families sharing an ancestral 8p23 haplotype. This gene, microcephalin, is expressed in the developing cerebral cortex of the fetal brain. Further study of this and related genes may provide important new insights into neocortical development and evolution.
Collapse
|
41
|
Abstract
Pseudogenes are commonly encountered during investigation of the genomes of a wide range of life forms. This review concentrates on vertebrate, and in particular mammalian, pseudogenes and describes their origin and subsequent evolution. Consideration is also given to pseudogenes that are transcribed and to the unusual group of genes that exist at the interface between functional genes and non-functional pseudogenes. As the sequences of different genomes are characterised, the recognition and interpretation of pseudogene sequences will become more important and have a greater impact in the field of molecular genetics.
Collapse
Affiliation(s)
- A J Mighell
- Molecular Medicine Unit, The University of Leeds, Clinical Sciences Building, St. James's University Hospital, Leeds, UK.
| | | | | | | |
Collapse
|
42
|
Abstract
Immunohistochemistry has the potential to be a powerful research tool. However, immunohistochemical studies are frequently undertaken without regard to the complexities and subtleties of these useful techniques. This review aims to address the problems and limitations that are often encountered, and the procedures that should be considered in both the planning and interpretation of immunohistochemical studies. Particular reference is made to the generation of functionally different protein isoforms from a single gene by alternative splicing and post-translational modifications, primary antibody selection, the effects of tissue manipulation such as fixation and antigen retrieval, the need for appropriate controls and interpretation of staining patterns.
Collapse
|
43
|
Mighell AJ, High AS. Histological identification of carcinoma in 21 gauge needle tracks after fine needle aspiration biopsy of head and neck carcinoma. J Clin Pathol 1998; 51:241-3. [PMID: 9659269 PMCID: PMC500648 DOI: 10.1136/jcp.51.3.241] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Six cancer resection specimens were thoroughly sectioned and microscopically examined at areas known to have been around 21 gauge fine needle aspiration (FNA) biopsy sites, in an attempt to identify needle tracks. All cases had an interval of not less than 10 days between FNA biopsy and surgery. Foci of tumour were identified histologically in needle tracks from two patients with carcinoma. This is the first instance, outside of experimental animal models, of histologically confirmed, viable tumour spread in FNA biopsy tracks. Although this complication is not common and is of unknown clinical significance, it is one that all clinicians who undertake FNA of malignant neoplasms should be aware of.
Collapse
Affiliation(s)
- A J Mighell
- Diagnostic Services, Leeds Dental Institute, UK
| | | |
Collapse
|
44
|
Abstract
Alu sequences are frequently encountered during study of human genomic nucleic acid and form a major component of repetitive DNA. This review describes the origin of Alu sequences and their subsequent amplification and evolution into distinct subfamilies. In recent years a number of different functional roles for Alu sequences have been described. The multiple influences of Alu sequences on RNA polymerase II-mediated gene expression and the presence of Alu sequences in RNA polymerase III-generated transcripts are discussed.
Collapse
Affiliation(s)
- A J Mighell
- Molecular Medicine Unit, The University of Leeds, St. James's University Hospital, UK.
| | | | | |
Collapse
|
45
|
Mighell AJ, Thompson J, Hume WJ, Markham AF, Robinson PA. Human tenascin-C: identification of a novel type III repeat in oral cancer and of novel splice variants in normal, malignant and reactive oral mucosae. Int J Cancer 1997; 72:236-40. [PMID: 9219826 DOI: 10.1002/(sici)1097-0215(19970717)72:2<236::aid-ijc6>3.0.co;2-s] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Tenascin-C is a mosaic, linear glycoprotein that is up-regulated during many normal and pathological processes involving either cell migration or tissue morphogenesis, such as invasion of malignant cells and wound healing. Human tenascin-C contains 8 consecutive type III fibronectin (TNCfn) domains that are involved in alternative splicing and potentially generate a large number of isoforms that code for tenascin-C proteins with subtly different functions. Human tenascin-C splice variants were investigated by RT-PCR in a range of normal and pathological oral mucosal tissues. A novel, 9th human TNCfn domain involved in alternative splicing was identified. It shares 70% nucleic acid and 55% protein sequence homology with chicken TNCfn-ad2. As in avians, this novel repeat was located between TNCfn-B and TNCfn-ad1 and accordingly was designated human TNCfn-ad2. Human TNCfn-ad2 was detected in only 2 of 10 oral cancers. However, TNCfn-ad2 was absent from 40 normal, reactive, pre-malignant and other oral mucosal specimens investigated. Previous studies have described 8 splice variant transcripts for human tenascin-C. By systematic investigation we identified further novel splice variants for human tenascin-C. Furthermore, our results indicate that many potential splice variants probably do not exist in the tissues investigated. Thus, we have demonstrated that human tenascin-C transcripts generate a complex but selected repertoire of different alternative splice products.
Collapse
Affiliation(s)
- A J Mighell
- Molecular Medicine Unit, St. James's University Hospital, Leeds, UK.
| | | | | | | | | |
Collapse
|
46
|
Abstract
This study aimed to establish patterns of cellular fibronectin mRNA splice variants in normal oral mucosa, oral squamous cell carcinoma, oral leukoplakias with and without atypia, and focal reactive overgrowths of oral mucosa. Particular emphasis was placed on evaluation of either the EDA or EDB domains as markers of malignancy. Total RNA was extracted from normal oral mucosa, oral squamous cell carcinoma, oral leukoplakias with and without atypia, reactive epulides, fibroepithelial polyps and denture-related hyperplasia. Reverse transcriptase polymerase chain reaction (RT-PCR) was used to identify different fibronectin transcripts at three splice sites (EDA, EDB and IIICS). All the tissues investigated produced EDA+, EDA-, EDB+ and EDB- splice variants, and this study did not support RT-PCR-based detection of either EDA or EDB domains as markers of malignancy in oral tissues. Variations in IIICS splice patterns were observed, although these were not specific to any lesion group. In particular, there were differences in either the inclusion or omission of the domain coding for the CS-5 binding site for alpha 4 beta 1 integrin, whereas the CS-1 binding site for alpha 4 beta 1 integrin was typically present when additional domains were included at the IIICS splice site. In conclusion, complex patterns of fibronectin splice variant transcripts exist in normal and pathological oral mucosa. This may reflect the multiple biological functions identified for fibronectin proteins, although the significance of different specific fibronectin splice variants has yet to be fully elucidated.
Collapse
Affiliation(s)
- A J Mighell
- Molecular Medicine Unit, St James's University Hospital, Leeds, UK
| | | | | | | | | |
Collapse
|
47
|
Mighell AJ, Robinson PA, Hume WJ. Histochemical and immunohistochemical localisation of elastic system fibres in focal reactive overgrowths of oral mucosa. J Oral Pathol Med 1997; 26:153-8. [PMID: 9176788 DOI: 10.1111/j.1600-0714.1997.tb00450.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Eight specimens each of the following groups were investigated: gingival pyogenic granuloma, fibrous epulis, calcifying fibrous epulis, peripheral giant cell granuloma, giant cell fibroma (four gingival, four non-gingival), denture-irritation hyperplasia and fibroepithelial polyp. These lesions have diverse histopathological appearances but the composition of their connective tissue is poorly defined. The elastic system consists of a complex mixture of glycoproteins that in normal oral mucosa form three differentially distributed fibre types; oxytalan, elaunin and elastic. The elastic system was investigated by Verhoeff's haematoxylin stain, aldehyde fuchsin staining and an anti-elastin monoclonal antibody. Elastin was identified in all fibroepithelial polyps and denture-irritation hyperplasias, but in none of the other lesions. In particular, this identified a distinct difference in the extracellular matrix between the giant cell fibroma and fibroepithelial polyp. Many of the epulides included only oxytalan fibres, but the presence of oxytalan fibres did not follow any pattern within either a single lesion group, or between different lesions. However, the presence of oxytalan fibres in the absence of elastin does not necessarily support a periodontal ligament origin for reactive epulides.
Collapse
Affiliation(s)
- A J Mighell
- Division of Dental Surgery, Leeds Dental Institute, UK
| | | | | |
Collapse
|
48
|
Abstract
Immunohistochemical investigation of PCNA and Ki-67, two diverse nuclear proteins essential to the cell cycle, was undertaken in archival, formalin-fixed and paraffin-embedded specimens of giant cell fibroma (GCF) and peripheral giant cell granuloma (PGCG++). GCF multinucleated cell nuclei were mostly PCNA+, although there was variability in staining intensity. This indicates heterogeneity in nuclear PCNA metabolism of GCF multinucleated cells, and it is possible that the most intensely stained nuclei have passed through the cell cycle more recently compared to the less immunoreactive nuclei. However, the absence of Ki-67 immunoreactivity in GCF multinucleated cells, and absence of mitoses in GCF multinucleated cells, suggests that cell cycling in the absence of cytokinesis is not involved in GCF multinucleated cell formation. Alternatively, GCF multinucleated cells possibly form by fusion of mononuclear cells previously identified as fibroblasts, although this theory cannot be confirmed by the data presented in this study, and the histogenesis of GCF multinucleated cells remains unclear. In contrast, absence of either PCNA or Ki-67 immunoreactivity in PGCG multinucleated cells is consistent with an osteoclast lineage and formation from differentiated mononuclear cells.
Collapse
Affiliation(s)
- A J Mighell
- Division of Dental Surgery, Leeds Dental Institute, United Kingdom
| | | | | |
Collapse
|
49
|
Abstract
Focal reactive overgrowths of oral mucosa were investigated in the following groups: gingival pyogenic granuloma, fibrous epulis, calcifying fibrous epulis, peripheral giant cell granuloma, giant cell fibroma, fibroepithelial polyp and denture-related fibrous hyperplasia (n = 8 for each group). We hypothesised that immunoreactivity to tenascin-C, a functional protein associated with connective tissue organisation and cell migration, would be differentially distributed in individual lesions and between lesion groups. Staining patterns for giant cell fibromas and fibroepithelial polyps were similar to those reported for normal mucosa. By contrast, additional staining was observed in the other lesion groups, although immunoreactivity was variable and not specific to each lesion group. Strong immunoreactivity was observed around blood vessels lined with plump endothelial cells and in regions where keratinocytes were migrating over ulcerated surfaces. Interlacing collagenous fascicles could be either strongly or weakly immunoreactive, with either fibrillar or diffuse staining. Localised staining was observed around, but not within, areas of calcification.
Collapse
Affiliation(s)
- A J Mighell
- Division of Dental Surgery, Leeds Dental Institute, United Kingdom
| | | | | |
Collapse
|
50
|
Abstract
A report of an 87-year-old Caucasian female with an extensive sebaceous carcinoma of the parotid gland is presented. The computed tomographic characteristics of this rare neoplasm are reported for the first time.
Collapse
Affiliation(s)
- A J Mighell
- Department of Oral & Facial Surgery, Sunderland District General Hospital, UK
| | | | | |
Collapse
|