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Rraku E, Kerstjens-Frederikse WS, Swertz MA, Dijkhuizen T, van Ravenswaaij-Arts CMA, Engwerda A. The phenotypic spectrum of terminal and subterminal 6p deletions based on a social media-derived cohort and literature review. Orphanet J Rare Dis 2023; 18:68. [PMID: 36964621 PMCID: PMC10039519 DOI: 10.1186/s13023-023-02670-0] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 03/11/2023] [Indexed: 03/26/2023] Open
Abstract
BACKGROUND Terminal 6p deletions are rare, and information on their clinical consequences is scarce, which impedes optimal management and follow-up by clinicians. The parent-driven Chromosome 6 Project collaborates with families of affected children worldwide to better understand the clinical effects of chromosome 6 aberrations and to support clinical guidance. A microarray report is required for participation, and detailed phenotype information is collected directly from parents through a multilingual web-based questionnaire. Information collected from parents is then combined with case data from literature reports. Here, we present our findings on 13 newly identified patients and 46 literature cases with genotypically well-characterised terminal and subterminal 6p deletions. We provide phenotype descriptions for both the whole group and for subgroups based on deletion size and HI gene content. RESULTS The total group shared a common phenotype characterised by ocular anterior segment dysgenesis, vision problems, brain malformations, congenital defects of the cardiac septa and valves, mild to moderate hearing impairment, eye movement abnormalities, hypotonia, mild developmental delay and dysmorphic features. These characteristics were observed in all subgroups where FOXC1 was included in the deletion, confirming a dominant role for this gene. Additional characteristics were seen in individuals with terminal deletions exceeding 4.02 Mb, namely complex heart defects, corpus callosum abnormalities, kidney abnormalities and orofacial clefting. Some of these additional features may be related to the loss of other genes in the terminal 6p region, such as RREB1 for the cardiac phenotypes and TUBB2A and TUBB2B for the cerebral phenotypes. In the newly identified patients, we observed previously unreported features including gastrointestinal problems, neurological abnormalities, balance problems and sleep disturbances. CONCLUSIONS We present an overview of the phenotypic characteristics observed in terminal and subterminal 6p deletions. This reveals a common phenotype that can be highly attributable to haploinsufficiency of FOXC1, with a possible additional effect of other genes in the 6p25 region. We also delineate the developmental abilities of affected individuals and report on previously unrecognised features, showing the added benefit of collecting information directly from parents. Based on our overview, we provide recommendations for clinical surveillance to support clinicians, patients and families.
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Affiliation(s)
- Eleana Rraku
- Department of Genetics, University of Groningen, University Medical Centre Groningen, Groningen, The Netherlands
| | | | - Morris A Swertz
- Department of Genetics, University of Groningen, University Medical Centre Groningen, Groningen, The Netherlands
| | - Trijnie Dijkhuizen
- Department of Genetics, University of Groningen, University Medical Centre Groningen, Groningen, The Netherlands
| | - Conny M A van Ravenswaaij-Arts
- Department of Genetics, University of Groningen, University Medical Centre Groningen, Groningen, The Netherlands.
- ATN/Jonx, Groningen, The Netherlands.
| | - Aafke Engwerda
- Department of Genetics, University of Groningen, University Medical Centre Groningen, Groningen, The Netherlands
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Engwerda A, Frentz B, Rraku E, de Souza NFS, Swertz MA, Plantinga M, Kerstjens-Frederikse WS, Ranchor AV, van Ravenswaaij-Arts CMA. Parent-reported phenotype data on chromosome 6 aberrations collected via an online questionnaire: data consistency and data availability. Orphanet J Rare Dis 2023; 18:60. [PMID: 36935495 PMCID: PMC10024830 DOI: 10.1186/s13023-023-02657-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [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: 11/01/2022] [Accepted: 02/27/2023] [Indexed: 03/21/2023] Open
Abstract
BACKGROUND Even with the introduction of new genetic techniques that enable accurate genomic characterization, knowledge about the phenotypic spectrum of rare chromosomal disorders is still limited, both in literature and existing databases. Yet this clinical information is of utmost importance for health professionals and the parents of children with rare diseases. Since existing databases are often hampered by the limited time and willingness of health professionals to input new data, we collected phenotype data directly from parents of children with a chromosome 6 disorder. These parents were reached via social media, and the information was collected via the online Chromosome 6 Questionnaire, which includes 115 main questions on congenital abnormalities, medical problems, behaviour, growth and development. METHODS Here, we assess data consistency by comparing parent-reported phenotypes to phenotypes based on copies of medical files for the same individual (n = 20) and data availability by comparing the data available on specific characteristics reported by parents (n = 34) to data available in existing literature (n = 39). RESULTS The reported answers to the main questions on phenotype characteristics were 85-95% consistent, and the consistency of answers to subsequent more detailed questions was 77-96%. For all but two main questions, significantly more data was collected from parents via the Chromosome 6 Questionnaire than was currently available in literature. For the topics developmental delay and brain abnormalities, no significant difference in the amount of available data was found. The only feature for which significantly more data was available in literature was a sub-question on the type of brain abnormality present. CONCLUSION This is the first study to compare phenotype data collected directly from parents to data extracted from medical files on the same individuals. We found that the data was highly consistent, and phenotype data collected via the online Chromosome 6 Questionnaire resulted in more available information on most clinical characteristics when compared to phenotypes reported in literature reports thus far. We encourage active patient participation in rare disease research and have shown that parent-reported phenotypes are reliable and contribute to our knowledge of the phenotypic spectrum of rare chromosomal disorders.
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Affiliation(s)
- Aafke Engwerda
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | | | - Eleana Rraku
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Nadia F Simoes de Souza
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Morris A Swertz
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Mirjam Plantinga
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | | | - Adelita V Ranchor
- Department of Health Psychology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Conny M A van Ravenswaaij-Arts
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
- ATN/Jonx, Groningen, The Netherlands.
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Engwerda A, Kerstjens-Frederikse WS, Corsten-Janssen N, Dijkhuizen T, van Ravenswaaij-Arts CMA. The phenotypic spectrum of terminal 6q deletions based on a large cohort derived from social media and literature: a prominent role for DLL1. Orphanet J Rare Dis 2023; 18:59. [PMID: 36935482 PMCID: PMC10024851 DOI: 10.1186/s13023-023-02658-w] [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: 10/31/2022] [Accepted: 02/27/2023] [Indexed: 03/21/2023] Open
Abstract
BACKGROUND Terminal 6q deletions are rare, and the number of well-defined published cases is limited. Since parents of children with these aberrations often search the internet and unite via international social media platforms, these dedicated platforms may hold valuable knowledge about additional cases. The Chromosome 6 Project is a collaboration between researchers and clinicians at the University Medical Center Groningen and members of a Chromosome 6 support group on Facebook. The aim of the project is to improve the surveillance of patients with chromosome 6 aberrations and the support for their families by increasing the available information about these rare aberrations. This parent-driven research project makes use of information collected directly from parents via a multilingual online questionnaire. Here, we report our findings on 93 individuals with terminal 6q deletions and 11 individuals with interstitial 6q26q27 deletions, a cohort that includes 38 newly identified individuals. RESULTS Using this cohort, we can identify a common terminal 6q deletion phenotype that includes microcephaly, dysplastic outer ears, hypertelorism, vision problems, abnormal eye movements, dental abnormalities, feeding problems, recurrent infections, respiratory problems, spinal cord abnormalities, abnormal vertebrae, scoliosis, joint hypermobility, brain abnormalities (ventriculomegaly/hydrocephaly, corpus callosum abnormality and cortical dysplasia), seizures, hypotonia, ataxia, torticollis, balance problems, developmental delay, sleeping problems and hyperactivity. Other frequently reported clinical characteristics are congenital heart defects, kidney problems, abnormalities of the female genitalia, spina bifida, anal abnormalities, positional foot deformities, hypertonia and self-harming behaviour. The phenotypes were comparable up to a deletion size of 7.1 Mb, and most features could be attributed to the terminally located gene DLL1. Larger deletions that include QKI (> 7.1 Mb) lead to a more severe phenotype that includes additional clinical characteristics. CONCLUSIONS Terminal 6q deletions cause a common but highly variable phenotype. Most clinical characteristics can be linked to the smallest terminal 6q deletions that include the gene DLL1 (> 500 kb). Based on our findings, we provide recommendations for clinical follow-up and surveillance of individuals with terminal 6q deletions.
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Affiliation(s)
- Aafke Engwerda
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | | | - Nicole Corsten-Janssen
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Trijnie Dijkhuizen
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Conny M A van Ravenswaaij-Arts
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
- ATN/Jonx, Groningen, The Netherlands.
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Thomas C, Thierfelder F, Träger M, Soschinski P, Müther M, Edelmann D, Förster A, Geiler C, Kim HY, Filipski K, Harter PN, Schittenhelm J, Eckert F, Ntoulias G, May SA, Stummer W, Onken J, Vajkoczy P, Schüller U, Heppner FL, Capper D, Koch A, Kaul D, Paulus W, Hasselblatt M, Schweizer L. TERT promoter mutation and chromosome 6 loss define a high-risk subtype of ependymoma evolving from posterior fossa subependymoma. Acta Neuropathol 2021; 141:959-970. [PMID: 33755803 PMCID: PMC8113189 DOI: 10.1007/s00401-021-02300-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [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: 02/26/2021] [Revised: 03/16/2021] [Accepted: 03/17/2021] [Indexed: 02/06/2023]
Abstract
Subependymomas are benign tumors characteristically encountered in the posterior fossa of adults that show distinct epigenetic profiles assigned to the molecular group “subependymoma, posterior fossa” (PFSE) of the recently established DNA methylation-based classification of central nervous system tumors. In contrast, most posterior fossa ependymomas exhibit a more aggressive biological behavior and are allocated to the molecular subgroups PFA or PFB. A subset of ependymomas shows epigenetic similarities with subependymomas, but the precise biology of these tumors and their potential relationships remain unknown. We therefore set out to characterize epigenetic traits, mutational profiles, and clinical outcomes of 50 posterior fossa ependymal tumors of the PFSE group. On histo-morphology, these tumors comprised 12 ependymomas, 14 subependymomas and 24 tumors with mixed ependymoma–subependymoma morphology. Mixed ependymoma–subependymoma tumors varied in their extent of ependymoma differentiation (2–95%) but consistently exhibited global epigenetic profiles of the PFSE group. Selective methylome analysis of microdissected tumor components revealed CpG signatures in mixed tumors that coalesce with their pure counterparts. Loss of chr6 (20/50 cases), as well as TERT mutations (21/50 cases), were frequent events enriched in tumors with pure ependymoma morphology (p < 0.001) and confined to areas with ependymoma differentiation in mixed tumors. Clinically, pure ependymoma phenotype, chr6 loss, and TERT mutations were associated with shorter progression-free survival (each p < 0.001). In conclusion, our results suggest that subependymomas may acquire genetic and epigenetic changes throughout tumor evolution giving rise to subclones with ependymoma morphology (resulting in mixed tumors) that eventually overpopulate the subependymoma component (pure PFSE ependymomas).
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Affiliation(s)
- Christian Thomas
- Institute of Neuropathology, University Hospital Münster, Münster, Germany
| | - Felix Thierfelder
- German Cancer Consortium (DKTK), Partner Site Berlin, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Malte Träger
- Department of Radiation Oncology and Radiotherapy, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Augustenburger Platz 1, 13353, Berlin, Germany
| | - Patrick Soschinski
- Institute of Neuropathology, University Hospital Münster, Münster, Germany
| | - Michael Müther
- Department of Neurosurgery, University Hospital Münster, Münster, Germany
| | - Dominic Edelmann
- Division of Biostatistics, German Cancer Research Center, Heidelberg, Germany
| | - Alexandra Förster
- Department of Neuropathology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Charitéplatz 1, 10117, Berlin, Germany
| | - Carola Geiler
- Department of Neuropathology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Charitéplatz 1, 10117, Berlin, Germany
| | - Hee-Yeong Kim
- German Cancer Consortium (DKTK), Partner Site Berlin, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Katharina Filipski
- Neurological Institute (Edinger Institute), Goethe University, Frankfurt am Main, Germany
- German Cancer Consortium (DKTK), Partner Site Frankfurt/Mainz, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Patrick N Harter
- Neurological Institute (Edinger Institute), Goethe University, Frankfurt am Main, Germany
- German Cancer Consortium (DKTK), Partner Site Frankfurt/Mainz, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Frankfurt Cancer Institute (FCI), Frankfurt am Main, Germany
| | - Jens Schittenhelm
- Department of Neuropathology, Institute of Pathology and Neuropathology, University of Tübingen, Tübingen, Germany
| | - Franziska Eckert
- Department of Radiooncology, University Hospital Tübingen, Tübingen, Germany
| | - Georgios Ntoulias
- Department of Neurosurgery, Vivantes Klinikum Neukölln, Berlin, Germany
| | - Sven-Axel May
- Department of Neurosurgery, Klinikum Chemnitz, Chemnitz, Germany
| | - Walter Stummer
- Department of Neurosurgery, University Hospital Münster, Münster, Germany
| | - Julia Onken
- Department of Neurosurgery, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Charitéplatz 1, 10117, Berlin, Germany
| | - Peter Vajkoczy
- Department of Neurosurgery, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Charitéplatz 1, 10117, Berlin, Germany
| | - Ulrich Schüller
- Department of Neuropathology, University Hospital Hamburg-Eppendorf, Hamburg, Germany
- Research Institute Children's Cancer Center Hamburg, Hamburg, Germany
- Department of Pediatric Hematology and Oncology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Frank L Heppner
- German Cancer Consortium (DKTK), Partner Site Berlin, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Department of Neuropathology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Charitéplatz 1, 10117, Berlin, Germany
- Cluster of Excellence, NeuroCure, Charitéplatz 1, 10117, Berlin, Germany
- German Center for Neurodegenerative Diseases (DZNE) Berlin, 10117, Berlin, Germany
| | - David Capper
- German Cancer Consortium (DKTK), Partner Site Berlin, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Department of Neuropathology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Charitéplatz 1, 10117, Berlin, Germany
| | - Arend Koch
- German Cancer Consortium (DKTK), Partner Site Berlin, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Department of Neuropathology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Charitéplatz 1, 10117, Berlin, Germany
| | - David Kaul
- Department of Radiation Oncology and Radiotherapy, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Augustenburger Platz 1, 13353, Berlin, Germany
| | - Werner Paulus
- Institute of Neuropathology, University Hospital Münster, Münster, Germany
| | - Martin Hasselblatt
- Institute of Neuropathology, University Hospital Münster, Münster, Germany
| | - Leonille Schweizer
- German Cancer Consortium (DKTK), Partner Site Berlin, German Cancer Research Center (DKFZ), Heidelberg, Germany.
- Department of Neuropathology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Charitéplatz 1, 10117, Berlin, Germany.
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Holzmann C, Helmke B, Bullerdiek J. Gross genetic alterations and genetic heterogeneity in a periductal stromal tumor of the breast. Mol Cytogenet 2020; 13:49. [PMID: 33292379 DOI: 10.1186/s13039-020-00516-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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: 06/25/2020] [Accepted: 11/02/2020] [Indexed: 12/05/2022] Open
Abstract
Background Periductal stromal tumors of the breast are exceedingly rare biphasic breast tumors with close morphological relationship to phyllodes tumors. So far, results of genetic analyses on these tumors have not been reported. Case presentation A 50 year old female patient was admitted to the hospital because of a palpable lump in her right breast with a diameter of approximately 5–6 cm which was surgically removed by lumpectomy. Histologic examination revealed a biphasic breast tumor classified as periductal stromal tumor. Array analysis showed a pseudotetraploid tumor with a copy number of 4 for most of the chromosomes. In addition, further changes of chromosomes 1, 5, and 6 were noted but there were no mutations of MED12 as those frequently seen in fibroadenomas or phyllodes tumors. Conclusions The genetic alterations observed indicate karyotypic evolution leading to marked heterogeneity which fits with the tumor´s histologic and cytologic appearance as well as with its malignant behavior. Because of the absence of genetic similarities with phyllodes tumors, the case does not offer evidence for a common entity but rather suggests the existence of two independent entities.
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Korsgaard T, Joshi S, Andersen RF, Moeller K, Seeman T, Podracká L, Eiberg H, Rittig S. Human leukocyte antigen association with familial steroid-sensitive nephrotic syndrome. Eur J Pediatr 2020; 179:1481-1486. [PMID: 32198629 DOI: 10.1007/s00431-020-03634-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 03/11/2020] [Accepted: 03/11/2020] [Indexed: 12/26/2022]
Abstract
Steroid-sensitive nephrotic syndrome (SSNS) is the most common form of nephrotic syndrome in childhood. Cases with the familial occurrence of SSNS suggest that genetics may play a role in the disease. Human leucocyte antigen (HLA) alleles have been associated with SSNS. We present genetic findings in nine families (44 participants), each with at least two affected siblings. A total of 19 patients were affected with familial SSNS. Six of nine families showed linkage to markers on chromosome 6p (27.29-33.97 Mbp) (Hg19), especially to markers D6S1629 and D6S1560 on HLA dense region in this location. Interestingly, we also found linkage of disease phenotype of familial SSNS on chromosome 15 (91.7-96.9 Mbp) (Hg19) with a logarithm of odds (LOD) score Z = 3.02.Conclusion: Our findings confirm the linkage of HLA markers on chromosome 6, which strengthens the association of HLA alleles in SSNS. What is Known: • Human leukocyte antigen (HLA) alleles have been associated with idiopathic steroid-sensitive nephrotic syndrome (SSNS). Only few studies have investigated the association between HLA alleles and familial SSNS. What is New: • We present evidence of linkage of familial SSNS to chromosome 6p (27.29-33.97 Mbp) (Hg19), especially to markers D6S1629 and D6S1560 on HLA dense region in this location. We also found linkage of the disease phenotype of familial SSNS on chromosome 15 (91.7-96.9 Mbp) (Hg19) with a logarithm of odds (LOD) score of Z = 3.02 following autosomal recessive inheritance pattern.
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Affiliation(s)
- Trine Korsgaard
- Department of Pediatric and Adolescent Medicine, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, DK-8200, Aarhus N, Denmark.
| | - Shivani Joshi
- Department of Clinical Medicine, Child and Youth Research Laboratory, Aarhus University, Palle Juul-Jensens Boulevard 99, DK-8200, Aarhus N, Denmark
| | - Rene F Andersen
- Department of Pediatric and Adolescent Medicine, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, DK-8200, Aarhus N, Denmark
| | - Kristina Moeller
- Department of Pediatrics and Adolescent Medicine, Klinkum Link der Weser, Bremen, Germany
| | - Tomás Seeman
- Department of Pediatrics, Charles University in Prague - 2nd Faculty of Medicine, Praha 5, Czech Republic
| | - Ludmila Podracká
- 1st Department of Pediatrics, Children's Hospital and Medical School Comenius University Bratislava, Bratislava, Slovakia
| | - Hans Eiberg
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Science, The Panum Institute, 3B Blegdamsvej, 2200, Copenhagen N, Denmark
| | - Søren Rittig
- Department of Pediatric and Adolescent Medicine, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, DK-8200, Aarhus N, Denmark
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Kerr ER, Stuhlmiller GM, Maha GC, Ladd MA, Mikhail FM, Koester RP, Hurst ACE. Maternal uniparental isodisomy for chromosome 6 discovered by paternity testing: a case report. Mol Cytogenet 2018; 11:60. [PMID: 30598700 DOI: 10.1186/s13039-018-0411-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [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: 08/29/2018] [Accepted: 12/10/2018] [Indexed: 01/14/2023] Open
Abstract
Background Uniparental disomy (UPD) is a rare condition in which a child inherits both copies of a chromosome or chromosome segment from one parent. Medical consequences of UPD may include abnormal imprinting, unmasking of genetic disease, and somatic mosaicism; alternatively, the condition may be clinically silent. We present a case of maternal UPD for chromosome 6, a rare condition previously reported less than 20 times. In our patient with a normal phenotype, the condition was discovered through abnormal paternity testing results. Uniparental isodisomy is a rare cause of discordant parentage testing results, but it is an important phenomenon to recognize. Case presentation We present a female born at 32 weeks gestational age with birth weight 10–25%ile when corrected for prematurity. Paternity testing was obtained for legal reasons, and initial results appeared to exclude the alleged father. However, the lab performed additional testing which indicated that the patient was homozygous for maternal alleles for all three tested loci located on chromosome 6. Based on these results, the patient was referred for a medical genetics evaluation for possible maternal uniparental disomy. She presented for her consultation at 10 months of age and appeared to be developing appropriately. Her age-adjusted weight, length, and head circumference were <3%ile, 10%ile, and 25%ile respectively. Chromosomal microarray testing confirmed maternal UPD6. The patient was seen again at 14 months of age, and her weight and length were 10–25%ile. She had not developed concerning symptoms or physical exam findings. Conclusions The presence of UPD, especially in asymptomatic patients, has implications for paternity testing, as standard methods may miss cases of both isodisomy and heterodisomy. This rare inheritance pattern should be considered when discordant paternity results come under suspicion. It is unusual for a parentage testing lab to perform the amount of testing done for this case, but the initial inconsistencies necessitated further investigation. UPD6 has uncertain effects and variable phenotypes, so this patient’s genetic abnormality likely would have gone undiscovered if not for the non-medical indication for the laboratory analysis. Her asymptomatic presentation raises the possibility that UPD may be more common than previously estimated.
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Abstract
Neuroblastoma (NB) is the most common extracranial solid tumor in childhood. This malignancy shows a wide spectrum of clinical outcome and its prognosis is conditioned by manifold biological and genetic factors. We investigated the tumor genetic profile and clinical data of 29 patients with NB by multiplex ligation-dependent probe amplification (MLPA) to assess therapeutic risk. In 18 of these tumors, MYCN status was assessed by fluorescence in situ hybridization (FISH). Copy number variation was also determined for confirming MLPA findings in two 6p loci. We found 2p, 7q and 17q gains, and 1p and 11q losses as the most frequent chromosome alterations in this cohort. FISH confirmed all cases of MYCN amplification detected by MLPA. In view of unexpected 6p imbalance, copy number variation of two 6p loci was assessed for validating MLPA findings. Based on clinical data and genetic profiles, patients were stratified in pretreatment risk groups according to international consensus. MLPA proved to be effective for detecting multiple genetic alterations in all chromosome regions as requested by the International Neuroblastoma Risk Group (INRG) for therapeutic stratification. Moreover, this technique proved to be cost effective, reliable, only requiring standard PCR equipment, and attractive for routine analysis. However, the observed 6p imbalances made PKHD1 and DCDC2 inadequate for control loci. This must be considered when designing commercial MLPA kits for NB. Finally, four patients showed a normal MLPA profile, suggesting that NB might have a more complex genetic pattern than the one assessed by presently available MLPA kits.
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Affiliation(s)
- Régis Afonso Costa
- Genetics Program, Instituto Nacional de Câncer, Rua André Cavalcanti 37, Rio de Janeiro, RJ, 20231-050, Brazil.,Department of Genetics, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Héctor N Seuánez
- Genetics Program, Instituto Nacional de Câncer, Rua André Cavalcanti 37, Rio de Janeiro, RJ, 20231-050, Brazil. .,Department of Genetics, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
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Eggermann T, Oehl-Jaschkowitz B, Dicks S, Thomas W, Kanber D, Albrecht B, Begemann M, Kurth I, Beygo J, Buiting K. The maternal uniparental disomy of chromosome 6 (upd(6)mat) "phenotype": result of placental trisomy 6 mosaicism? Mol Genet Genomic Med 2017; 5:668-677. [PMID: 29178649 PMCID: PMC5702562 DOI: 10.1002/mgg3.324] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [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: 05/12/2017] [Revised: 06/28/2017] [Accepted: 07/05/2017] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Maternal uniparental disomy of chromosome 6 (upd(6)mat) is a rare finding and its clinical relevance is currently unclear. Based on clinical data from two new cases and patients from the literature, the pathogenetic significance of upd(6)mat is delineated. METHODS Own cases were molecularly characterized for isodisomic uniparental regions on chromosome 6. For further cases with upd(6)mat, a literature search was conducted and genetic and clinical data were ascertained. RESULTS Comparison of isodisomic regions between the new upd(6)mat cases and those from four reports did not reveal any common isodisomic region. Among the patients with available cytogenetic data, five had a normal karyotype in lymphocytes, whereas a trisomy 6 (mosaicism) was detected prenatally in four cases. A common clinical picture was not obvious in upd(6)mat, but intrauterine growth restriction (IUGR) and preterm delivery were frequent. CONCLUSION A common upd(6)mat phenotype is not obvious, but placental dysfunction due to trisomy 6 mosaicism probably contributes to IUGR and preterm delivery. In fact, other clinical features observed in upd(6)mat patients might be caused by homozygosity of recessive mutations or by an undetected trisomy 6 cell line. Upd(6)mat itself is not associated with clinical features, and can rather be regarded as a biomarker. In case upd(6)mat is detected, the cause for the phenotype is identified indirectly, but the UPD is not the basic cause.
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Affiliation(s)
- Thomas Eggermann
- Medical Faculty, Institute of Human Genetics, RWTH Aachen University, Aachen, Germany
| | | | - Severin Dicks
- Medical Faculty, Institute of Human Genetics, RWTH Aachen University, Aachen, Germany
| | | | - Deniz Kanber
- Institute of Human Genetics, University of Essen, Essen, Germany
| | - Beate Albrecht
- Institute of Human Genetics, University of Essen, Essen, Germany
| | - Matthias Begemann
- Medical Faculty, Institute of Human Genetics, RWTH Aachen University, Aachen, Germany
| | - Ingo Kurth
- Medical Faculty, Institute of Human Genetics, RWTH Aachen University, Aachen, Germany
| | - Jasmin Beygo
- Institute of Human Genetics, University of Essen, Essen, Germany
| | - Karin Buiting
- Institute of Human Genetics, University of Essen, Essen, Germany
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10
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Fernández Pineda M, Ramírez-Cheyne J, Isaza C, Saldarriaga W. [A case of partial 1p36.1 deletion and partial trisomy 6p diagnosed by karyotype]. ACTA ACUST UNITED AC 2016; 87:395-400. [PMID: 27262749 DOI: 10.1016/j.rchipe.2016.04.010] [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: 05/20/2015] [Revised: 04/16/2016] [Accepted: 04/28/2016] [Indexed: 11/30/2022]
Abstract
The deletion of chromosomal region 1p36 is one of the most common sub-telomeric microdeletion syndromes and has distinctive dysmorphic features. On the other hand, partial trisomy of the short arm of chromosome 6 is a rare chromosomal abnormality with a variable phenotype. OBJECTIVE To report a case with both chromosome abnormalities, and to highlight the importance of the karyotype as a diagnostic tool in dysmorphology. CLINICAL CASE The case of is presented of a two month-old infant with several craniofacial anomalies, neck haemangioma, sacral pit, rhizomelic shortening, small hands and feet, left unilateral cryptorchidism, and hypotonia. The infant also suffered intrauterine growth restriction and is the product of the eighth pregnancy of a 28 years old woman. Due to the unspecific findings in phenotype, a karyotype was requested, which showed a partial deletion of 1p36.1 and a partial trisomy of chromosome 6. CONCLUSION The development of new techniques in molecular biology has improved diagnostic possibilities in medical genetics. However, the traditional karyotype remains as an important diagnostic tool in patients with multiple congenital anomalies.
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Affiliation(s)
| | - Julián Ramírez-Cheyne
- Profesor, Departamento de Morfología, Escuela de Ciencias Básicas Médicas, Universidad del Valle, Cali, Colombia.
| | - Carolina Isaza
- Profesor, Departamento de Morfología, Escuela de Ciencias Básicas Médicas, Universidad del Valle, Cali, Colombia
| | - Wilmar Saldarriaga
- Profesor, Departamento de Morfología, Escuela de Ciencias Básicas Médicas, Universidad del Valle, Cali, Colombia; Gineco Obstetra, Hospital Universitario del Valle, Cali, Colombia
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11
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Joshi PA, Poduri A, Kothare SV. Juvenile myoclonic epilepsy and narcolepsy: A series of three cases. Epilepsy Behav 2015; 51:163-5. [PMID: 26283305 DOI: 10.1016/j.yebeh.2015.07.030] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2015] [Revised: 07/20/2015] [Accepted: 07/22/2015] [Indexed: 10/23/2022]
Abstract
OBJECTIVE This paper sets out to demonstrate the coexistence of juvenile myoclonic epilepsy (JME) and narcolepsy that raises the possibility of a shared genetic predisposition to both conditions. METHODS The electronic medical records (EMRs) were searched for narcolepsy and JME over 10years. RESULTS We identified three young adult women diagnosed with JME in their teenage years, with myoclonic, generalized tonic-clonic, and absence seizure semiologies, along with psychiatric comorbidity, well managed on lamotrigine and/or levetiracetam. Our patients were also found to have disturbed sleep preceding the diagnosis of JME by many years, including excessive daytime sleepiness (EDS), fragmented nocturnal sleep, hypnagogic vivid hallucinations, and REM behavior disorder along with daytime cataplexy. They were ultimately diagnosed with coexisting narcolepsy, confirmed by sleep studies and multiple sleep latency testing, along with positive genetic testing for HLA-DQB1*0602 in all three patients. Stimulants, selective serotonin receptor inhibitors, and/or sodium oxybate were used to successfully treat their narcolepsy. SIGNIFICANCE The coexistence of JME and narcolepsy has not been well recognized and may be clinically relevant. In addition, it raises the possibility of a shared genetic predisposition to both conditions.
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Affiliation(s)
- Puja Aggarwal Joshi
- Department of Neurology, New York University Langone School of Medicine, New York, NY 10016, USA
| | - Annapurna Poduri
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Children's Hospital Boston and Harvard Medical School, Boston, MA 02115, USA
| | - Sanjeev V Kothare
- Comprehensive Epilepsy Center, Department of Neurology, New York University Langone Medical Center, New York, NY 10016, USA.
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12
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Spiegel S, Chiu A, James AS, Jentsch JD, Karlsgodt KH. Recognition deficits in mice carrying mutations of genes encoding BLOC-1 subunits pallidin or dysbindin. Genes Brain Behav 2015; 14:618-24. [PMID: 26294018 DOI: 10.1111/gbb.12240] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Revised: 08/04/2015] [Accepted: 08/14/2015] [Indexed: 01/31/2023]
Abstract
Numerous studies have implicated DTNBP1, the gene encoding dystrobrevin-binding protein or dysbindin, as a candidate risk gene for schizophrenia, though this relationship remains somewhat controversial. Variation in dysbindin, and its location on chromosome 6p, has been associated with cognitive processes, including those relying on a complex system of glutamatergic and dopaminergic interactions. Dysbindin is one of the seven protein subunits that comprise the biogenesis of lysosome-related organelles complex 1 (BLOC-1). Dysbindin protein levels are lower in mice with null mutations in pallidin, another gene in the BLOC-1, and pallidin levels are lower in mice with null mutations in the dysbindin gene, suggesting that multiple subunit proteins must be present to form a functional oligomeric complex. Furthermore, pallidin and dysbindin have similar distribution patterns in a mouse and human brain. Here, we investigated whether the apparent correspondence of pallid and dysbindin at the level of gene expression is also found at the level of behavior. Hypothesizing a mutation leading to underexpression of either of these proteins should show similar phenotypic effects, we studied recognition memory in both strains using the novel object recognition task (NORT) and social novelty recognition task (SNRT). We found that mice with a null mutation in either gene are impaired on SNRT and NORT when compared with wild-type controls. These results support the conclusion that deficits consistent with recognition memory impairment, a cognitive function that is impaired in schizophrenia, result from either pallidin or dysbindin mutations, possibly through degradation of BLOC-1 expression and/or function.
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Affiliation(s)
- S Spiegel
- Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA
| | - A Chiu
- Department of Pharmacology, University of California Irvine, Irvine
| | - A S James
- Department of Psychology, UCLA, Los Angeles, CA
| | - J D Jentsch
- Department of Psychology, UCLA, Los Angeles, CA.,Department of Psychiatry, UCLA, Los Angeles, CA
| | - K H Karlsgodt
- Psychiatry Research Division, Zucker Hillside Hospital, Glen Oaks.,Psychiatry Research Division, Feinstein Institute for Medical Research, Manhasset.,Department of Psychiatry, Hofstra North Shore-LIJ School of Medicine, Hempstead, NY, USA
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13
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Borchers CH, Kast J, Foster LJ, Siu KWM, Overall CM, Binkowski TA, Hildebrand WH, Scherer A, Mansoor M, Keown PA. The Human Proteome Organization Chromosome 6 Consortium: integrating chromosome-centric and biology/disease driven strategies. J Proteomics 2014; 100:60-7. [PMID: 23933161 PMCID: PMC4096956 DOI: 10.1016/j.jprot.2013.08.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [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: 06/25/2013] [Accepted: 08/01/2013] [Indexed: 11/20/2022]
Abstract
The Human Proteome Project (HPP) is designed to generate a comprehensive map of the protein-based molecular architecture of the human body, to provide a resource to help elucidate biological and molecular function, and to advance diagnosis and treatment of diseases. Within this framework, the chromosome-based HPP (C-HPP) has allocated responsibility for mapping individual chromosomes by country or region, while the biology/disease HPP (B/D-HPP) coordinates these teams in cross-functional disease-based groups. Chromosome 6 (Ch6) provides an excellent model for integration of these two tasks. This metacentric chromosome has a complement of 1002-1034 genes that code for known, novel or putative proteins. Ch6 is functionally associated with more than 120 major human diseases, many with high population prevalence, devastating clinical impact and profound societal consequences. The unique combination of genomic, proteomic, metabolomic, phenomic and health services data being drawn together within the Ch6 program has enormous potential to advance personalized medicine by promoting robust biomarkers, subunit vaccines and new drug targets. The strong liaison between the clinical and laboratory teams, and the structured framework for technology transfer and health policy decisions within Canada will increase the speed and efficacy of this transition, and the value of this translational research. BIOLOGICAL SIGNIFICANCE Canada has been selected to play a leading role in the international Human Proteome Project, the global counterpart of the Human Genome Project designed to understand the structure and function of the human proteome in health and disease. Canada will lead an international team focusing on chromosome 6, which is functionally associated with more than 120 major human diseases, including immune and inflammatory disorders affecting the brain, skeletal system, heart and blood vessels, lungs, kidney, liver, gastrointestinal tract and endocrine system. Many of these chronic and persistent diseases have a high population prevalence, devastating clinical impact and profound societal consequences. As a result, they impose a multi-billion dollar economic burden on Canada and on all advanced societies through direct costs of patient care, the loss of health and productivity, and extensive caregiver burden. There is no definitive treatment at the present time for any of these disorders. The manuscript outlines the research which will involve a systematic assessment of all chromosome 6 genes, development of a knowledge base, and development of assays and reagents for all chromosome 6 proteins. We feel that the informatic infrastructure and MRM assays developed will place the chromosome 6 consortium in an excellent position to be a leading player in this major international research initiative. This article is part of a Special Issue: Can Proteomics Fill the Gap Between Genomics and Phenotypes?
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Affiliation(s)
- C H Borchers
- University of Victoria/Genome BC Proteomics Centre, Victoria, BC, Canada
| | - J Kast
- Biomedical Research Centre, University of British Columbia, Vancouver, BC, Canada
| | - L J Foster
- Centre for High Throughput Biology, University of British Columbia, BC, Canada
| | - K W M Siu
- Centre for Research in Mass Spectrometry, York University, Ontario, Canada
| | - C M Overall
- Centre for Blood Research, Faculty of Dentistry, University of British Columbia, Canada
| | - T A Binkowski
- Midwest Centre for Structural Genomics, Argonne National Laboratory and Computation Institute, University of Chicago, USA
| | - W H Hildebrand
- Department of Microbiology and Immunology, University of Oklahoma, OK, USA
| | - A Scherer
- Australian Genome Research Facility, Walter and Eliza Hall Institute, Parkville, Australia
| | - M Mansoor
- Department Medicine, University of British Columbia, Vancouver, BC, Canada
| | - P A Keown
- Department Medicine, University of British Columbia, Vancouver, BC, Canada; Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada.
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14
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Abstract
Familial aggregation and the studies of twins indicate that heredity contributes to multiple sclerosis (MS) risk. Immunologic studies of leukocyte antigens subsequently followed by gene-mapping techniques identified the primary MS susceptibility locus to be within the major histocompatibility complex (MHC). The primary risk allele is HLA-DRB1*15, although other alleles of this gene also influence MS susceptibility. Other genes within the MHC also contribute to MS susceptibility. Genome-wide association studies have identified over 50 additional common variants of genes across the genome. Estimates suggest that there may be as many as 200 genes involved in MS susceptibility. In addition to these common polymorphisms, studies have identified several rare risk alleles in some families. Interestingly, the majority of the genes identified have known immunologic functions and many contribute to the risk of inheriting other autoimmune diseases. Genetic variants in the vitamin D metabolic pathway have also been identified. That vitamin D contributes to MS susceptibility as both an environmental as well as genetic risk factor underscores the importance of this metabolic pathway in disease pathogenesis. Current efforts are focused on understanding how the myriad of genetic risk alleles interact within networks to influence MS risk at family level as well as within populations.
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Affiliation(s)
- Bruce A C Cree
- Department of Neurology, University of California, San Francisco, USA.
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