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Chen X, Fang Z, Pang T, Li D, Lei J, Jiang W, Li H. Identification of novel variations of oculocutaneous albinism type 2 with Prader-Willi syndrome/Angelman syndrome in two Chinese families. Front Genet 2023; 14:1135698. [PMID: 36950135 PMCID: PMC10025288 DOI: 10.3389/fgene.2023.1135698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 02/15/2023] [Indexed: 03/08/2023] Open
Abstract
Objective: Oculocutaneous albinism (OCA) is an autosomal recessive disorder caused by a variety of genomic variations. Our aim is to identify the molecular basis of OCA in two families and lay the foundation for prenatal diagnosis. Methods: Four types of OCA-causing mutations in the TYR, p, TYRP1, or SLC45A2 genes were screened. Linkage analysis was performed because the mutations found in the p gene violated the laws of classical Mendelian heredity. Primer-walking sequencing combined with microsatellite and single-nucleotide polymorphism analysis was used to ascertain deletion ranges. Bioinformatics methods were used to assess the pathogenicity of the new mutations. Results: Proband 1 was diagnosed as OCA2 with Prader-Willi syndrome (PWS) due to a novel atypical paternal deletion (chromosome 15: 22330347-26089649) and a pathogenic mutation, c.1327G>A (Val443Ile), in the p gene of the maternal chromosome. The prenatal diagnosis results for family 1 indicated the fetus was a heterozygous carrier (c.1327G>A in the p gene) with a normal phenotype. Proband 2 was diagnosed as OCA2 with Angelman syndrome (AS) due to a typical maternal deletion of chromosome 15q11-q13 and a novel mutation, c.1514T>C (Phe505Ser), in the p gene of the paternal chromosome. This novel mutation c.1514T>C (Phe505Ser) in the p gene was predicted as a pathogenic mutation. Conclusion: Our study has shown clear genotype-phenotype correlations in patients affected by distinct deletions of the PWS or AS region and missense mutations in the p gene. Our results have enriched the mutation spectrum of albinism diseases and provided insights for more accurate diagnosis and genetic counseling.
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Affiliation(s)
- XiaoFei Chen
- Maternity and Child Care Center of Dezhou, DeZhou, China
- Department of Medical Genetics, Zhongshan School of Medicine, Guangzhou, China
| | - ZiShui Fang
- Department of Medical Genetics, Zhongshan School of Medicine, Guangzhou, China
- Beijing Key Laboratory of Urogenital Diseases (Male) Molecular Diagnosis and Treatment Center, National Urological Cancer Center, Department of Urology, Peking University First Hospital, Institution of Urology, Peking University, Beijing, China
| | - Ting Pang
- Department of Medical Genetics, Zhongshan School of Medicine, Guangzhou, China
| | - DongZhi Li
- Prenatal Diagnosis Center, Guangzhou Women and Children’s Medical Center, Guangzhou, China
| | - Jie Lei
- Department of Medical Genetics, Zhongshan School of Medicine, Guangzhou, China
- Shenzhen Nanshan Maternity and Child Healthcare Hospital, Shenzhen, China
- *Correspondence: Jie Lei, ; WeiYing Jiang, ; HongYi Li,
| | - WeiYing Jiang
- Department of Medical Genetics, Zhongshan School of Medicine, Guangzhou, China
- *Correspondence: Jie Lei, ; WeiYing Jiang, ; HongYi Li,
| | - HongYi Li
- Department of Medical Genetics, Zhongshan School of Medicine, Guangzhou, China
- *Correspondence: Jie Lei, ; WeiYing Jiang, ; HongYi Li,
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Fukiyama Y, Tonari M, Matsuo J, Oku H, Sugasawa J, Shimakawa S, Ogihara T, Okamoto N, Ikeda T. A Case of Fundus Oculi Albinoticus Diagnosed as Angelman Syndrome by Genetic Testing. Case Rep Ophthalmol 2018; 9:102-107. [PMID: 29643790 PMCID: PMC5892312 DOI: 10.1159/000485964] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 12/03/2017] [Indexed: 11/19/2022] Open
Abstract
PURPOSE To report a case of fundus oculi albinoticus diagnosed as Angelman syndrome (AS) via genetic testing. CASE REPORT This study reports on a 4-year-old boy. Since he had been having respiratory disturbance since birth, he underwent a complete physical examination to investigate the cause. The results indicated that he had various brain congenital abnormalities, such as a thin corpus callosum, as well as hydronephrosis, an atrial septal defect, and skin similar to patients with fundus oculi albinoticus. Examination revealed bilateral fundus oculi albinoticus, mild iridic hypopigmentation, optic atrophy, and poor visual tracking. Genetic testing revealed a deletion in the Prader-Willi syndrome/AS region on chromosome 15, and together with the results of methylation analysis, his condition was diagnosed as AS. Follow-up examinations revealed no change in the fundus oculi albinoticus and optic atrophy, nor did they indicate poor visual tracking. CONCLUSIONS When fundus oculi albinoticus and optic atrophy are observed in patients with multiple malformations, AS should be considered as a differential diagnosis.
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Affiliation(s)
- Yurie Fukiyama
- Department of Ophthalmology, Osaka Medical College, Takatsuki-City, Japan
| | - Masahiro Tonari
- Department of Ophthalmology, Osaka Medical College, Takatsuki-City, Japan
| | - Junko Matsuo
- Department of Ophthalmology, Osaka Medical College, Takatsuki-City, Japan
| | - Hidehiro Oku
- Department of Ophthalmology, Osaka Medical College, Takatsuki-City, Japan
| | - Jun Sugasawa
- Department of Ophthalmology, Osaka Medical College, Takatsuki-City, Japan
| | - Shuichi Shimakawa
- Department of Pediatrics, Osaka Medical College, Takatsuki-City, Japan
| | - Tohru Ogihara
- Department of Neonatology, Osaka Medical College, Takatsuki-City, Japan
| | - Nobuhiko Okamoto
- Department of Medical Genetics, Osaka Women's and Children's Hospital, Izumi-City, Japan
| | - Tsunehiko Ikeda
- Department of Ophthalmology, Osaka Medical College, Takatsuki-City, Japan
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3
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Kronick B, John RM. Unseen Impairment: Pediatric Primary Care Management of Oculocutaneous Albinism 2. J Nurse Pract 2016. [DOI: 10.1016/j.nurpra.2016.07.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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4
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Poot M, Haaf T. Mechanisms of Origin, Phenotypic Effects and Diagnostic Implications of Complex Chromosome Rearrangements. Mol Syndromol 2015; 6:110-34. [PMID: 26732513 DOI: 10.1159/000438812] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/23/2015] [Indexed: 01/08/2023] Open
Abstract
Complex chromosome rearrangements (CCRs) are currently defined as structural genome variations that involve more than 2 chromosome breaks and result in exchanges of chromosomal segments. They are thought to be extremely rare, but their detection rate is rising because of improvements in molecular cytogenetic technology. Their population frequency is also underestimated, since many CCRs may not elicit a phenotypic effect. CCRs may be the result of fork stalling and template switching, microhomology-mediated break-induced repair, breakage-fusion-bridge cycles, or chromothripsis. Patients with chromosomal instability syndromes show elevated rates of CCRs due to impaired DNA double-strand break responses during meiosis. Therefore, the putative functions of the proteins encoded by ATM, BLM, WRN, ATR, MRE11, NBS1, and RAD51 in preventing CCRs are discussed. CCRs may exert a pathogenic effect by either (1) gene dosage-dependent mechanisms, e.g. haploinsufficiency, (2) mechanisms based on disruption of the genomic architecture, such that genes, parts of genes or regulatory elements are truncated, fused or relocated and thus their interactions disturbed - these mechanisms will predominantly affect gene expression - or (3) mixed mutation mechanisms in which a CCR on one chromosome is combined with a different type of mutation on the other chromosome. Such inferred mechanisms of pathogenicity need corroboration by mRNA sequencing. Also, future studies with in vitro models, such as inducible pluripotent stem cells from patients with CCRs, and transgenic model organisms should substantiate current inferences regarding putative pathogenic effects of CCRs. The ramifications of the growing body of information on CCRs for clinical and experimental genetics and future treatment modalities are briefly illustrated with 2 cases, one of which suggests KDM4C (JMJD2C) as a novel candidate gene for mental retardation.
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Affiliation(s)
- Martin Poot
- Department of Human Genetics, University of Würzburg, Würzburg, Germany
| | - Thomas Haaf
- Department of Human Genetics, University of Würzburg, Würzburg, Germany
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5
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Accordino RE, Lucarelli J, Yan AC. Cutaneous Disease in Autism Spectrum Disorder: A Review. Pediatr Dermatol 2015; 32:455-60. [PMID: 25824343 DOI: 10.1111/pde.12582] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Dermatologic comorbid symptoms and conditions in persons with autism spectrum disorder (ASD) are compelling for several reasons, including problems with tactile sensory dysfunction in this population, a large number of syndromes with dermatologic findings and high rates of autism, nutritional and hormonal problems in ASD and their dermatologic manifestations, and the potential for overrepresentation of dermatologic symptoms that are neurobehavioral in nature. The current article reviews the available literature on the prevalence of comorbid dermatologic symptoms and conditions in children with ASD and identifies strategies for diagnosing and managing cutaneous disease in this population.
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Affiliation(s)
- Robert E Accordino
- Division of Child and Adolescent Psychiatry, Massachusetts General Hospital, Boston, Massachusetts
| | - Jennifer Lucarelli
- Division of Developmental Medicine, Boston Children's Hospital, Boston, Massachusetts
| | - Albert C Yan
- Section of Pediatric Dermatology, Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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Abstract
"Angelman syndrome" (AS) is a neurodevelopmental disorder whose main features are intellectual disability, lack of speech, seizures, and a characteristic behavioral profile. The behavioral features of AS include a happy demeanor, easily provoked laughter, short attention span, hypermotoric behavior, mouthing of objects, sleep disturbance, and an affinity for water. Microcephaly and subtle dysmorphic features, as well as ataxia and other movement disturbances, are additional features seen in most affected individuals. AS is due to deficient expression of the ubiquitin protein ligase E3A (UBE3A) gene, which displays paternal imprinting. There are four molecular classes of AS, and some genotype-phenotype correlations have emerged. Much remains to be understood regarding how insufficiency of E6-AP, the protein product of UBE3A, results in the observed neurodevelopmental deficits. Studies of mouse models of AS have implicated UBE3A in experience-dependent synaptic remodeling.
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Affiliation(s)
- Lynne M Bird
- Department of Pediatrics, University of California, Division of Genetics, Rady Children’s Hospital, San Diego, California, USA
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7
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Rooryck C, Morice F, Lacombe D, Taieb A, Arveiler B. Genetic basis of oculocutaneous albinism. ACTA ACUST UNITED AC 2014. [DOI: 10.1586/edm.09.53] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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8
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Morice-Picard F, Lasseaux E, Cailley D, Gros A, Toutain J, Plaisant C, Simon D, François S, Gilbert-Dussardier B, Kaplan J, Rooryck C, Lacombe D, Arveiler B. High-resolution array-CGH in patients with oculocutaneous albinism identifies new deletions of theTYR, OCA2, andSLC45A2genes and a complex rearrangement of theOCA2gene. Pigment Cell Melanoma Res 2013; 27:59-71. [DOI: 10.1111/pcmr.12173] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Accepted: 09/20/2013] [Indexed: 11/29/2022]
Affiliation(s)
- Fanny Morice-Picard
- Service de Génétique Médicale; CHU de Bordeaux; Bordeaux France
- Maladies Rares: Génétique et Métabolisme (MRGM) EA4576; Univ. Bordeaux; Bordeaux France
| | | | | | - Audrey Gros
- Service de Génétique Médicale; CHU de Bordeaux; Bordeaux France
| | - Jérome Toutain
- Service de Génétique Médicale; CHU de Bordeaux; Bordeaux France
| | | | - Delphine Simon
- Maladies Rares: Génétique et Métabolisme (MRGM) EA4576; Univ. Bordeaux; Bordeaux France
| | - Stéphane François
- Maladies Rares: Génétique et Métabolisme (MRGM) EA4576; Univ. Bordeaux; Bordeaux France
| | | | - Josseline Kaplan
- Laboratoire de Génétique; CHU Paris -Hôpital Necker - Enfants Malades; Paris France
| | - Caroline Rooryck
- Service de Génétique Médicale; CHU de Bordeaux; Bordeaux France
- Maladies Rares: Génétique et Métabolisme (MRGM) EA4576; Univ. Bordeaux; Bordeaux France
| | - Didier Lacombe
- Service de Génétique Médicale; CHU de Bordeaux; Bordeaux France
- Maladies Rares: Génétique et Métabolisme (MRGM) EA4576; Univ. Bordeaux; Bordeaux France
| | - Benoit Arveiler
- Service de Génétique Médicale; CHU de Bordeaux; Bordeaux France
- Maladies Rares: Génétique et Métabolisme (MRGM) EA4576; Univ. Bordeaux; Bordeaux France
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Simeonov DR, Wang X, Wang C, Sergeev Y, Dolinska M, Bower M, Fischer R, Winer D, Dubrovsky G, Balog JZ, Huizing M, Hart R, Zein WM, Gahl WA, Brooks BP, Adams DR. DNA variations in oculocutaneous albinism: an updated mutation list and current outstanding issues in molecular diagnostics. Hum Mutat 2013; 34:827-35. [PMID: 23504663 DOI: 10.1002/humu.22315] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 03/08/2013] [Indexed: 12/20/2022]
Abstract
Oculocutaneous albinism (OCA) is a rare genetic disorder of melanin synthesis that results in hypopigmented hair, skin, and eyes. There are four types of OCA caused by mutations in TYR (OCA-1), OCA2 (OCA-2), TYRP1 (OCA-3), or SLC45A2 (OCA-4). Here we report 22 novel mutations in the OCA genes; 14 from a cohort of 61 patients seen as part of the NIH OCA Natural History Study and eight from a prior study at the University of Minnesota. We also include a comprehensive list of almost 600 previously reported OCA mutations along with ethnicity information, carrier frequencies, and in silico pathogenicity predictions as a supplement. In addition to discussing the clinical and molecular features of OCA, we address the cases of apparent missing heritability. In our cohort, 26% of patients did not have two mutations in a single OCA gene. We demonstrate the utility of multiple detection methods to reveal mutations missed by Sanger sequencing. Finally, we review the TYR p.R402Q temperature-sensitive variant and confirm its association with cases of albinism with only one identifiable TYR mutation.
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Affiliation(s)
- Dimitre R Simeonov
- National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
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Reissmann M, Ludwig A. Pleiotropic effects of coat colour-associated mutations in humans, mice and other mammals. Semin Cell Dev Biol 2013; 24:576-86. [PMID: 23583561 DOI: 10.1016/j.semcdb.2013.03.014] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 03/27/2013] [Accepted: 03/28/2013] [Indexed: 12/20/2022]
Abstract
The characterisation of the pleiotropic effects of coat colour-associated mutations in mammals illustrates that sensory organs and nerves are particularly affected by disorders because of the shared origin of melanocytes and neurocytes in the neural crest; e.g. the eye-colour is a valuable indicator of disorders in pigment production and eye dysfunctions. Disorders related to coat colour-associated alleles also occur in the skin (melanoma), reproductive tract and immune system. Additionally, the coat colour phenotype of an individual influences its general behaviour and fitness. Mutations in the same genes often produce similar coat colours and pleiotropic effects in different species (e.g., KIT [reproductive disorders, lethality], EDNRB [megacolon] and LYST [CHS]). Whereas similar disorders and similar-looking coat colour phenotypes sometimes have a different genetic background (e.g., deafness [EDN3/EDNRB, MITF, PAX and SNAI2] and visual diseases [OCA2, RAB38, SLC24A5, SLC45A2, TRPM1 and TYR]). The human predilection for fancy phenotypes that ignore disorders and genetic defects is a major driving force for the increase of pleiotropic effects in domestic species and laboratory subjects since domestication has commenced approximately 18,000 years ago.
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Key Words
- AS
- ASIP
- ATRN
- Agouti signalling protein
- Albino
- Angelman syndrome
- Attractin (mahogany)
- BLOC
- Biogenesis of lysosomal organelles complex
- CCSD
- CHS
- CSD
- CSNB
- Canine congenital sensorineural deafness
- Chediak-Higashi syndrome
- Coat colour gene
- Congenital sensorineural deafness
- Congenital stationary night blindness
- Disorder
- EDN3
- EDNRB
- Endothelin 3
- Endothelin receptor type B
- Epistasis
- Fitness
- GS
- Griscelli syndrome (type 1 or 2)
- HPS
- HSCR
- Hermansky-Pudlak syndrome with different types
- Hirschsprung disease
- IPE
- Iris pigment epithelium
- KIT
- KIT ligand (steel factor)
- KITLG
- LFS
- LYST
- Lavender foal syndrome
- Lethal
- Leucism
- Lysosomal trafficking regulator
- MC1R
- MCOA
- MCOLN3
- MGRN1
- MITF
- MYO5A
- Mahogunin ring finger 1 (E3 ubiquitin protein ligase)
- Melanocortin 1 receptor
- Melanoma
- Microphthalmia-associated transcription factor
- Mucolipin 3 (TRPML3)
- Multiple congenital ocular anomalies
- Myosin VA (heavy chain 12, myoxin)
- OA
- OCA
- OCA2
- OLWS
- OSTM1
- Ocular albinism
- Oculocutaneous albinism II (pink-eye dilution homolog)
- Oculocutaneous albinism type 1–4
- Osteopetrosis associated transmembrane protein 1 (Grey lethal osteopetrosis)
- Overo lethal white syndrome
- PAX3
- PMEL
- PWS
- Paired box 3
- Pleiotropy
- Prader-Willi syndrome
- Premelanosome protein (Pmel17, SILV)
- RAB27A
- RAB27A member RAS oncogene family
- RAB38
- RAB38 member RAS oncogene family
- RPE
- Reproduction
- Retinal pigmented epithelium
- SLC24A5
- SLC2A9
- SLC45A2
- SNAI2
- STX17
- Snail homolog 2 (Drosophila), (SLUG), SOX10, SRY (sex determining region Y)-box 10
- Solute carrier family 2 (facilitated glucose transporter), member 9
- Solute carrier family 24, member 5
- Solute carrier family 45, member 2, MATP
- Syntaxin 17
- TRPM1
- TYR
- Tameness
- Transient receptor potential cation channel, subfamily M, member 1 (melastatin-1)
- Tyrosinase, TYRP1, Tyrosinase-related protein 1
- V-kit Hardy-Zuckerman 4 feline sarcoma viral oncogene homolog, tyrosine kinase receptor (c-kit)
- WS
- Waardenburg syndrome (type 1, type 2 combined with Tietz syndrome type 3 Klein-Waardenburg syndrome, type 4 Waardenburg-Shah syndrome)
- alpha-melanocyte-stimulating hormone
- αMSH
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Affiliation(s)
- Monika Reissmann
- Humboldt University Berlin, Department for Crop and Animal Sciences, Berlin, Germany.
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Abstract
Array-based genome-wide segmental aneuploidy screening detects both de novo and inherited copy number variations (CNVs). In sporadic patients de novo CNVs are interpreted as potentially pathogenic. However, a deletion, transmitted from a healthy parent, may be pathogenic if it overlaps with a mutated second allele inherited from the other healthy parent. To detect such events, we performed multiplex enrichment and next-generation sequencing of the entire coding sequence of all genes within unique hemizygous deletion regions in 20 patients (1.53 Mb capture footprint). Out of the detected 703 non-synonymous single-nucleotide variants (SNVs), 8 represented variants being unmasked by a hemizygous deletion. Although evaluation of inheritance patterns, Grantham matrix scores, evolutionary conservation and bioinformatic predictions did not consistently indicate pathogenicity of these variants, no definitive conclusions can be drawn without functional validation. However, in one patient with severe mental retardation, lack of speech, microcephaly, cheilognathopalatoschisis and bilateral hearing loss, we discovered a second smaller deletion, inherited from the other healthy parent, resulting in loss of both alleles of the highly conserved heat shock factor binding protein 1 (HSBP1) gene. Conceivably, inherited deletions may unmask rare pathogenic variants that may exert a phenotypic impact through a recessive mode of gene action.
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Low D, Chen KS. UBE3A regulates MC1R expression: a link to hypopigmentation in Angelman syndrome. Pigment Cell Melanoma Res 2011; 24:944-52. [DOI: 10.1111/j.1755-148x.2011.00884.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Michieletto P, Bonanni P, Pensiero S. Ophthalmic findings in Angelman syndrome. J AAPOS 2011; 15:158-61. [PMID: 21596294 DOI: 10.1016/j.jaapos.2010.12.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Revised: 12/03/2010] [Accepted: 12/06/2010] [Indexed: 01/16/2023]
Abstract
PURPOSE To provide detailed information about opthalmological findings in a group of patients with Angelman syndrome (AS). METHODS Consecutive patients with a genetically confirmed diagnosis of AS were submitted to ophthalmic and orthoptic examinations. Strabismus, visual acuity, cycloplegic refraction, and iris and fundus pigmentation were evaluated. Parents were also examined to compare the extent of fundus pigmentation. RESULTS A total of 34 patients were identified, representing 3 genetic classes: deletion, uniparental disomy, and mutation. Ametropia >1 D was present in 97% of cases: myopia in 9%, hyperopia in 76%, and astigmatism in 94%. Myopia and anisometropia were found only in the genetic deletion group. Strabismus, most frequently exotropia, was found in 24 patients (75%). Ocular hypopigmentation was observed in 18 subjects (53%), with choroidal involvement in 3 cases and isolated iris involvement in 4. Hypopigmentation was observed in all of the 3 genetic classes. CONCLUSIONS Ophthalmic alterations in AS were observed more frequently than has been previously reported, except for ocular hypopigmentation, which was observed less frequently.
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Affiliation(s)
- Paola Michieletto
- IRCCS Eugenio Medea, polo di Conegliano e Pieve di Soligo (TV), Italy
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14
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Poot M, van der Smagt J, Brilstra E, Bourgeron T. Disentangling the Myriad Genomics of Complex Disorders, Specifically Focusing on Autism, Epilepsy, and Schizophrenia. Cytogenet Genome Res 2011; 135:228-40. [DOI: 10.1159/000334064] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
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15
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High resolution mapping of OCA2 intragenic rearrangements and identification of a founder effect associated with a deletion in Polish albino patients. Hum Genet 2010; 129:199-208. [DOI: 10.1007/s00439-010-0913-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2010] [Accepted: 11/03/2010] [Indexed: 11/26/2022]
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Abstract
Angelman syndrome is characterized by severe developmental delay, speech impairment, gait ataxia and/or tremulousness of the limbs, and a unique behavioral phenotype that includes happy demeanor and excessive laughter. Microcephaly and seizures are common. Developmental delays are first noted at 3 to 6 months age, but the unique clinical features of the syndrome do not become manifest until after age 1 year. Management includes treatment of gastrointestinal symptoms, use of antiepileptic drugs for seizures, and provision of physical, occupational, and speech therapy with an emphasis on nonverbal methods of communication. The diagnosis rests on a combination of clinical criteria and molecular and/or cytogenetic testing. Analysis of parent-specific DNA methylation imprints in the 15q11.2-q13 chromosome region detects approximately 78% of individuals with lack of maternal contribution. Less than 1% of individuals have a visible chromosome rearrangement. UBE3A sequence analysis detects mutations in an additional 11% of individuals. The remaining 10% of individuals with classic phenotypic features of Angelman syndrome have a presently unidentified genetic mechanism and thus are not amenable to diagnostic testing. The risk to sibs of a proband depends on the genetic mechanism of the loss of the maternally contributed Angelman syndrome/Prader-Willi syndrome region: typically <1% for probands with a deletion or uniparental disomy; as high as 50% for probands with an imprinting defect or a mutation of UBE3A. Members of the mother's extended family are also at increased risk when an imprinting defect or a UBE3A mutation is present. Chromosome rearrangements may be inherited or de novo. Prenatal testing is possible for certain genetic mechanisms.
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Genome-wide gene expression profiling of the Angelman syndrome mice with Ube3a mutation. Eur J Hum Genet 2010; 18:1228-35. [PMID: 20571502 DOI: 10.1038/ejhg.2010.95] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Angelman syndrome (AS) is a human neurological disorder caused by lack of maternal UBE3A expression in the brain. UBE3A is known to function as both an ubiquitin-protein ligase (E3) and a coactivator for steroid receptors. Many ubiquitin targets, as well as interacting partners, of UBE3A have been identified. However, the pathogenesis of AS, and how deficiency of maternal UBE3A can upset cellular homeostasis, remains vague. In this study, we performed a genome-wide microarray analysis on the maternal Ube3a-deficient (Ube3a(m-/p+)) AS mouse to search for genes affected in the absence of Ube3a. We observed 64 differentially expressed transcripts (7 upregulated and 57 downregulated) showing more than 1.5-fold differences in expression (P<0.05). Pathway analysis shows that these genes are implicated in three major networks associated with cell signaling, nervous system development and cell death. Using quantitative reverse-transcription PCR, we validated the differential expression of genes (Fgf7, Glra1, Mc1r, Nr4a2, Slc5a7 and Epha6) that show functional relevance to AS phenotype. We also show that the protein level of melanocortin 1 receptor (Mc1r) and nuclear receptor subfamily 4, group A, member 2 (Nr4a2) in the AS mice cerebellum is decreased relative to that of the wild-type mice. Consistent with this finding, expression of small-interfering RNA that targets Ube3a in P19 cells caused downregulation of Mc1r and Nr4a2, whereas overexpression of Ube3a results in the upregulation of Mc1r and Nr4a2. These observation help in providing insights into the genesis of neurodevelopmental phenotype of AS and highlight specific area for future research.
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Friedman J, Adam S, Arbour L, Armstrong L, Baross A, Birch P, Boerkoel C, Chan S, Chai D, Delaney AD, Flibotte S, Gibson WT, Langlois S, Lemyre E, Li HI, MacLeod P, Mathers J, Michaud JL, McGillivray BC, Patel MS, Qian H, Rouleau GA, Van Allen MI, Yong SL, Zahir FR, Eydoux P, Marra MA. Detection of pathogenic copy number variants in children with idiopathic intellectual disability using 500 K SNP array genomic hybridization. BMC Genomics 2009; 10:526. [PMID: 19917086 PMCID: PMC2781027 DOI: 10.1186/1471-2164-10-526] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2009] [Accepted: 11/16/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Array genomic hybridization is being used clinically to detect pathogenic copy number variants in children with intellectual disability and other birth defects. However, there is no agreement regarding the kind of array, the distribution of probes across the genome, or the resolution that is most appropriate for clinical use. RESULTS We performed 500 K Affymetrix GeneChip array genomic hybridization in 100 idiopathic intellectual disability trios, each comprised of a child with intellectual disability of unknown cause and both unaffected parents. We found pathogenic genomic imbalance in 16 of these 100 individuals with idiopathic intellectual disability. In comparison, we had found pathogenic genomic imbalance in 11 of 100 children with idiopathic intellectual disability in a previous cohort who had been studied by 100 K GeneChip array genomic hybridization. Among 54 intellectual disability trios selected from the previous cohort who were re-tested with 500 K GeneChip array genomic hybridization, we identified all 10 previously-detected pathogenic genomic alterations and at least one additional pathogenic copy number variant that had not been detected with 100 K GeneChip array genomic hybridization. Many benign copy number variants, including one that was de novo, were also detected with 500 K array genomic hybridization, but it was possible to distinguish the benign and pathogenic copy number variants with confidence in all but 3 (1.9%) of the 154 intellectual disability trios studied. CONCLUSION Affymetrix GeneChip 500 K array genomic hybridization detected pathogenic genomic imbalance in 10 of 10 patients with idiopathic developmental disability in whom 100 K GeneChip array genomic hybridization had found genomic imbalance, 1 of 44 patients in whom 100 K GeneChip array genomic hybridization had found no abnormality, and 16 of 100 patients who had not previously been tested. Effective clinical interpretation of these studies requires considerable skill and experience.
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Affiliation(s)
- Jm Friedman
- Department of Medical Genetics, University of British Columbia, Vancouver, Canada.
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19
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Friedman JM. High-resolution array genomic hybridization in prenatal diagnosis. Prenat Diagn 2008; 29:20-8. [DOI: 10.1002/pd.2129] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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20
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Chiang PW, Spector E, Tsai ACH. Evidence suggesting the inheritance mode of the humanP gene in skin complexion is not strictly recessive. Am J Med Genet A 2008; 146A:1493-6. [DOI: 10.1002/ajmg.a.32321] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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21
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Flipsen-ten Berg K, van Hasselt PM, Eleveld MJ, van der Wijst SE, Hol FA, de Vroede MAM, Beemer FA, Hochstenbach PFR, Poot M. Unmasking of a hemizygous WFS1 gene mutation by a chromosome 4p deletion of 8.3 Mb in a patient with Wolf–Hirschhorn syndrome. Eur J Hum Genet 2007; 15:1132-8. [PMID: 17637805 DOI: 10.1038/sj.ejhg.5201899] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The Wolf-Hirschhorn syndrome (WHS (MIM 194190)), which is characterized by growth delay, mental retardation, epilepsy, facial dysmorphisms, and midline fusion defects, shows extensive phenotypic variability. Several of the proposed mutational and epigenetic mechanisms in this and other chromosomal deletion syndromes fail to explain the observed phenotypic variability. To explain the complex phenotype of a patient with WHS and features reminiscent of Wolfram syndrome (WFS (MIM 222300)), we performed extensive clinical evaluation and classical and molecular cytogenetic (GTG banding, FISH and array-CGH) and WFS1 gene mutation analyses. We detected an 8.3 Mb terminal deletion and an adjacent 2.6 Mb inverted duplication in the short arm of chromosome 4, which encompasses a gene associated with WFS (WFS1). In addition, a nonsense mutation in exon 8 of the WFS1 gene was found on the structurally normal chromosome 4. The combination of the 4p deletion with the WFS1 point mutation explains the complex phenotype presented by our patient. This case further illustrates that unmasking of hemizygous recessive mutations by chromosomal deletions represents an additional explanation for the phenotypic variability observed in chromosomal deletion disorders.
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Affiliation(s)
- Klara Flipsen-ten Berg
- Department of Medical Genetics, University Medical Centre Utrecht, Utrecht, The Netherlands.
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Friedman JM, Baross A, Delaney AD, Ally A, Arbour L, Armstrong L, Asano J, Bailey DK, Barber S, Birch P, Brown-John M, Cao M, Chan S, Charest DL, Farnoud N, Fernandes N, Flibotte S, Go A, Gibson WT, Holt RA, Jones SJM, Kennedy GC, Krzywinski M, Langlois S, Li HI, McGillivray BC, Nayar T, Pugh TJ, Rajcan-Separovic E, Schein JE, Schnerch A, Siddiqui A, Van Allen MI, Wilson G, Yong SL, Zahir F, Eydoux P, Marra MA. Oligonucleotide microarray analysis of genomic imbalance in children with mental retardation. Am J Hum Genet 2006; 79:500-13. [PMID: 16909388 PMCID: PMC1559542 DOI: 10.1086/507471] [Citation(s) in RCA: 225] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2006] [Accepted: 07/06/2006] [Indexed: 11/03/2022] Open
Abstract
The cause of mental retardation in one-third to one-half of all affected individuals is unknown. Microscopically detectable chromosomal abnormalities are the most frequently recognized cause, but gain or loss of chromosomal segments that are too small to be seen by conventional cytogenetic analysis has been found to be another important cause. Array-based methods offer a practical means of performing a high-resolution survey of the entire genome for submicroscopic copy-number variants. We studied 100 children with idiopathic mental retardation and normal results of standard chromosomal analysis, by use of whole-genome sampling analysis with Affymetrix GeneChip Human Mapping 100K arrays. We found de novo deletions as small as 178 kb in eight cases, de novo duplications as small as 1.1 Mb in two cases, and unsuspected mosaic trisomy 9 in another case. This technology can detect at least twice as many potentially pathogenic de novo copy-number variants as conventional cytogenetic analysis can in people with mental retardation.
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Affiliation(s)
- J M Friedman
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada.
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23
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Zou YS, McGrann PS, Uphoff TS, Van Dyke DL. A case of mosaic supernumerary ring chromosome 15 with two copies of the segment 15p11.1-q14. Am J Med Genet A 2006; 140:1663-8. [PMID: 16830338 DOI: 10.1002/ajmg.a.31339] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Although supernumerary marker chromosomes derived from chromosome 15 (SMC(15)) are the most common marker chromosome in humans, ring SMC(15)s are rare. Here we report on a 16-month-old patient who has a ring SMC(15) with two copies of the segment 15p11.1-q14 region. She exhibits hypotonia, developmental delay, speech delay, microstomia, micrognathia, and other mild dysmorphic features. The ring was present in 22% of her peripheral blood lymphocyte cells. FISH study revealed that the ring was derived from chromosome 15, and had neither telomere sequence nor satellite III paracentromeric DNA. It had alpha satellite DNA, and two copies of the segment 15q11.2 to CTD 2125J1 (at 15q14, 2.2 Mbp telomeric of the common breakpoint 5). The ring-containing cells had four copies of 15p11.1-q14. The ring can be described as r(15)(::p11.1 --> q14::q14 --> p11.1::). Southern-blot analysis of the methylation pattern in the PW/AS critical region showed biparental inheritance, and the ring was maternally derived. This patient's phenotype was comparable to ring SMC(15) patients with three copies of the Prader-Willi/Angelman syndrome (PWS/AS) critical region.
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Affiliation(s)
- Ying S Zou
- Cytogenetics Laboratory, Mayo Clinic, Rochester, Minnesota 55905, USA
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Williams CA, Beaudet AL, Clayton-Smith J, Knoll JH, Kyllerman M, Laan LA, Magenis RE, Moncla A, Schinzel AA, Summers JA, Wagstaff J. Angelman syndrome 2005: updated consensus for diagnostic criteria. Am J Med Genet A 2006; 140:413-8. [PMID: 16470747 DOI: 10.1002/ajmg.a.31074] [Citation(s) in RCA: 412] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In 1995, a consensus statement was published for the purpose of summarizing the salient clinical features of Angelman syndrome (AS) to assist the clinician in making a timely and accurate diagnosis. Considering the scientific advances made in the last 10 years, it is necessary now to review the validity of the original consensus criteria. As in the original consensus project, the methodology used for this review was to convene a group of scientists and clinicians, with experience in AS, to develop a concise consensus statement, supported by scientific publications where appropriate. It is hoped that this revised consensus document will facilitate further clinical study of individuals with proven AS, and assist in the evaluation of those who appear to have clinical features of AS but have normal laboratory diagnostic testing.
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Affiliation(s)
- Charles A Williams
- Department of Pediatrics, Division of Genetics, R.C. Philips Unit, University of Florida, Gainesville, Florida 32610, USA.
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Horsler K, Oliver C. The behavioural phenotype of Angelman syndrome. JOURNAL OF INTELLECTUAL DISABILITY RESEARCH : JIDR 2006; 50:33-53. [PMID: 16316429 DOI: 10.1111/j.1365-2788.2005.00730.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
BACKGROUND The purpose of this review is to examine the notion of a behavioural phenotype for Angelman syndrome and identify methodological and conceptual influences on the accepted presentation. METHODS Studies examining the behavioural characteristics associated with Angelman syndrome are reviewed and methodology is described. RESULTS Potential bias in the description of the phenotype emerges with the use of case and cohort studies with the absence of comparison groups. A trend in the literature from a direct gene effect to a socially mediated effect on laughter is evident. CONCLUSION Evidence for a behavioural phenotype of Angelman syndrome has begun to emerge. However, by adopting the concept of a 'behavioural phenotype', attention may become biased towards the underlying biological basis of the syndrome, with developmental and environmental factors being overlooked.
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Affiliation(s)
- K Horsler
- School of Psychology, University of Birmingham, Edgbaston, Birmingham, UK
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Abstract
The finding, during the last decade, that several common, clinically delineated syndromes are caused by submicroscopic deletions or, more rarely, by duplications, has provided a powerful tool in the annotation of the human genome. Since most microdeletion/microduplication syndromes are defined by a common deleted/duplicated region, abnormal dosage of genes located within these regions can explain the phenotypic similarities among individuals with a specific syndrome. As such, they provide a unique resource towards the genetic dissection of complex phenotypes such as congenital heart defects, mental and growth retardation and abnormal behaviour. In addition, the study of phenotypic differences in individuals with the same microdeletion syndrome may also become a treasury for the identification of modifying factors for complex phenotypes. The molecular analysis of these chromosomal anomalies has led to a growing understanding of their mechanisms of origin. Novel tools to uncover additional submicroscopic chromosomal anomalies at a higher resolution and higher speed, as well as the novel tools at hand for deciphering the modifying factors and epistatic interactors, are 'on the doorstep' and will, besides their obvious diagnostic role, play a pivotal role in the genetic dissection of complex phenotypes.
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Affiliation(s)
- Koen Devriendt
- Center for Human Genetics, University Hospital Leuven, Herestraat 49, B-3000 Leuven, Belgium
| | - Joris R Vermeesch
- Center for Human Genetics, University Hospital Leuven, Herestraat 49, B-3000 Leuven, Belgium
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Varela MC, Kok F, Otto PA, Koiffmann CP. Phenotypic variability in Angelman syndrome: comparison among different deletion classes and between deletion and UPD subjects. Eur J Hum Genet 2004; 12:987-92. [PMID: 15470370 DOI: 10.1038/sj.ejhg.5201264] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Angelman syndrome (AS) can result from either a 15q11-q13 deletion (del), paternal uniparental disomy (UPD), imprinting, or UBE3A mutations. Here, we describe the phenotypic and behavioral variability detected in 49 patients with different classes of deletions and nine patients with UPD. Diagnosis was made by methylation pattern analysis of exon 1 of the SNRPN-SNURF gene and by microsatellite profiling of loci within and outside the 15q11-q13 region. There were no major phenotypic differences between the two main classes (BP1-BP3; BP2-BP3) of AS deletion patients, except for the absence of vocalization, more prevalent in patients with BP1-BP3 deletions, and for the age of sitting without support, which was lower in patients with BP2-BP3 deletions. Our data suggest that gene deletions (NIPA1, NIPA2, CYF1P1, GCP5) mapped to the region between breakpoints BP1 and BP2 may be involved in the severity of speech impairment, since all BP1-BP3 deletion patients showed complete absence of vocalization, while 38.1% of the BP2-BP3 deletion patients were able to pronounce syllabic sounds, with doubtful meaning. Compared to UPD patients, deletion patients presented a higher incidence of swallowing disorders (73.9% del x 22.2% UPD) and hypotonia (73.3% del x 28.57% UPD). In addition, children with UPD showed better physical growth, fewer or no seizures, a lower incidence of microcephaly, less ataxia and higher cognitive skills. As a consequence of their milder or less typical phenotype, AS may remain undiagnosed, leading to an overall underdiagnosis of the disease.
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Affiliation(s)
- Monica Castro Varela
- Centro de Estudos do Genoma Humano, Department of Biology, Institute of Biosciences, University of São Paulo, São Paulo, SP, Brazil.
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