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1.
Hum Mutat ; 40(6): 765-787, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30825406

RESUMO

Inherited retinal disorders (IRD) represent clinically and genetically heterogeneous diseases. To date, pathogenic variants have been identified in ~260 genes. Albeit that many genes are implicated in IRD, for 30-50% of the cases, the gene defect is unknown. These cases may be explained by novel gene defects, by overlooked structural variants, by variants in intronic, promoter or more distant regulatory regions, and represent synonymous variants of known genes contributing to the dysfunction of the respective proteins. Patients with one subgroup of IRD, namely incomplete congenital stationary night blindness (icCSNB), show a very specific phenotype. The major cause of this condition is the presence of a hemizygous pathogenic variant in CACNA1F. A comprehensive study applying direct Sanger sequencing of the gene-coding regions, exome and genome sequencing applied to a large cohort of patients with a clinical diagnosis of icCSNB revealed indeed that seven of the 189 CACNA1F-related cases have intronic and synonymous disease-causing variants leading to missplicing as validated by minigene approaches. These findings highlight that gene-locus sequencing may be a very efficient method in detecting disease-causing variants in clinically well-characterized patients with a diagnosis of IRD, like icCSNB.

2.
Lancet ; 393(10173): 747-757, 2019 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-30712880

RESUMO

BACKGROUND: Fetal structural anomalies, which are detected by ultrasonography, have a range of genetic causes, including chromosomal aneuploidy, copy number variations (CNVs; which are detectable by chromosomal microarrays), and pathogenic sequence variants in developmental genes. Testing for aneuploidy and CNVs is routine during the investigation of fetal structural anomalies, but there is little information on the clinical usefulness of genome-wide next-generation sequencing in the prenatal setting. We therefore aimed to evaluate the proportion of fetuses with structural abnormalities that had identifiable variants in genes associated with developmental disorders when assessed with whole-exome sequencing (WES). METHODS: In this prospective cohort study, two groups in Birmingham and London recruited patients from 34 fetal medicine units in England and Scotland. We used whole-exome sequencing (WES) to evaluate the presence of genetic variants in developmental disorder genes (diagnostic genetic variants) in a cohort of fetuses with structural anomalies and samples from their parents, after exclusion of aneuploidy and large CNVs. Women were eligible for inclusion if they were undergoing invasive testing for identified nuchal translucency or structural anomalies in their fetus, as detected by ultrasound after 11 weeks of gestation. The partners of these women also had to consent to participate. Sequencing results were interpreted with a targeted virtual gene panel for developmental disorders that comprised 1628 genes. Genetic results related to fetal structural anomaly phenotypes were then validated and reported postnatally. The primary endpoint, which was assessed in all fetuses, was the detection of diagnostic genetic variants considered to have caused the fetal developmental anomaly. FINDINGS: The cohort was recruited between Oct 22, 2014, and June 29, 2017, and clinical data were collected until March 31, 2018. After exclusion of fetuses with aneuploidy and CNVs, 610 fetuses with structural anomalies and 1202 matched parental samples (analysed as 596 fetus-parental trios, including two sets of twins, and 14 fetus-parent dyads) were analysed by WES. After bioinformatic filtering and prioritisation according to allele frequency and effect on protein and inheritance pattern, 321 genetic variants (representing 255 potential diagnoses) were selected as potentially pathogenic genetic variants (diagnostic genetic variants), and these variants were reviewed by a multidisciplinary clinical review panel. A diagnostic genetic variant was identified in 52 (8·5%; 95% CI 6·4-11·0) of 610 fetuses assessed and an additional 24 (3·9%) fetuses had a variant of uncertain significance that had potential clinical usefulness. Detection of diagnostic genetic variants enabled us to distinguish between syndromic and non-syndromic fetal anomalies (eg, congenital heart disease only vs a syndrome with congenital heart disease and learning disability). Diagnostic genetic variants were present in 22 (15·4%) of 143 fetuses with multisystem anomalies (ie, more than one fetal structural anomaly), nine (11·1%) of 81 fetuses with cardiac anomalies, and ten (15·4%) of 65 fetuses with skeletal anomalies; these phenotypes were most commonly associated with diagnostic variants. However, diagnostic genetic variants were least common in fetuses with isolated increased nuchal translucency (≥4·0 mm) in the first trimester (in three [3·2%] of 93 fetuses). INTERPRETATION: WES facilitates genetic diagnosis of fetal structural anomalies, which enables more accurate predictions of fetal prognosis and risk of recurrence in future pregnancies. However, the overall detection of diagnostic genetic variants in a prospectively ascertained cohort with a broad range of fetal structural anomalies is lower than that suggested by previous smaller-scale studies of fewer phenotypes. WES improved the identification of genetic disorders in fetuses with structural abnormalities; however, before clinical implementation, careful consideration should be given to case selection to maximise clinical usefulness. FUNDING: UK Department of Health and Social Care and The Wellcome Trust.


Assuntos
Cariótipo Anormal/estatística & dados numéricos , Anormalidades Congênitas/genética , Desenvolvimento Fetal/genética , Feto/anormalidades , Sequenciamento Completo do Exoma/estatística & dados numéricos , Cariótipo Anormal/embriologia , Aborto Eugênico/estatística & dados numéricos , Aborto Espontâneo/epidemiologia , Anormalidades Congênitas/diagnóstico , Anormalidades Congênitas/epidemiologia , Variações do Número de Cópias de DNA/genética , Feminino , Feto/diagnóstico por imagem , Humanos , Recém-Nascido , Nascimento Vivo/epidemiologia , Masculino , Medição da Translucência Nucal , Pais , Morte Perinatal/etiologia , Gravidez , Estudos Prospectivos , Natimorto/epidemiologia , Sequenciamento Completo do Exoma/métodos
4.
Genet Med ; 20(10): 1236-1245, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29323665

RESUMO

PURPOSE: We delineate the clinical spectrum and describe the histology in arterial tortuosity syndrome (ATS), a rare connective tissue disorder characterized by tortuosity of the large and medium-sized arteries, caused by mutations in SLC2A10. METHODS: We retrospectively characterized 40 novel ATS families (50 patients) and reviewed the 52 previously reported patients. We performed histology and electron microscopy (EM) on skin and vascular biopsies and evaluated TGF-ß signaling with immunohistochemistry for pSMAD2 and CTGF. RESULTS: Stenoses, tortuosity, and aneurysm formation are widespread occurrences. Severe but rare vascular complications include early and aggressive aortic root aneurysms, neonatal intracranial bleeding, ischemic stroke, and gastric perforation. Thus far, no reports unequivocally document vascular dissections or ruptures. Of note, diaphragmatic hernia and infant respiratory distress syndrome (IRDS) are frequently observed. Skin and vascular biopsies show fragmented elastic fibers (EF) and increased collagen deposition. EM of skin EF shows a fragmented elastin core and a peripheral mantle of microfibrils of random directionality. Skin and end-stage diseased vascular tissue do not indicate increased TGF-ß signaling. CONCLUSION: Our findings warrant attention for IRDS and diaphragmatic hernia, close monitoring of the aortic root early in life, and extensive vascular imaging afterwards. EM on skin biopsies shows disease-specific abnormalities.

5.
Neuropediatrics ; 49(2): 118-122, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29253910

RESUMO

Alexander disease (AD) is a leukodystrophy caused by heterozygous mutations in the gene encoding the glial fibrillary acidic protein (GFAP). Currently, de novo heterozygous missense mutations in the GFAP gene are identified in over 95% of patients with AD. However, patients with biopsy-proven AD have been reported in whom no GFAP mutation has been identified. We report identical twin boys presenting in infancy with seizures and developmental delay in whom MR appearances were suggestive of AD with the exception of an unusual, bilateral, arc of calcification at the frontal white-gray junction. Initial mutation screening of the GFAP gene did not identify a mutation. Whole exome sequencing in both brothers revealed a de novo heterozygous in-frame deletion of the whole of exon 5 of the GFAP gene. Mutations in the GFAP gene are thought to result in a toxic effect of mutant GFAP disrupting the formation of the normal intermediate filament network and resulting in Rosenthal fiber formation, which has hitherto not been linked to exonic scale copy number variants in GFAP. Further studies on mutation negative AD patients are warranted to determine whether a similar mechanism underlies their disease.

7.
Eur J Hum Genet ; 24(5): 652-9, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26306646

RESUMO

The Koolen-de Vries syndrome (KdVS; OMIM #610443), also known as the 17q21.31 microdeletion syndrome, is a clinically heterogeneous disorder characterised by (neonatal) hypotonia, developmental delay, moderate intellectual disability, and characteristic facial dysmorphism. Expressive language development is particularly impaired compared with receptive language or motor skills. Other frequently reported features include social and friendly behaviour, epilepsy, musculoskeletal anomalies, congenital heart defects, urogenital malformations, and ectodermal anomalies. The syndrome is caused by a truncating variant in the KAT8 regulatory NSL complex unit 1 (KANSL1) gene or by a 17q21.31 microdeletion encompassing KANSL1. Herein we describe a novel cohort of 45 individuals with KdVS of whom 33 have a 17q21.31 microdeletion and 12 a single-nucleotide variant (SNV) in KANSL1 (19 males, 26 females; age range 7 months to 50 years). We provide guidance about the potential pitfalls in the laboratory testing and emphasise the challenges of KANSL1 variant calling and DNA copy number analysis in the complex 17q21.31 region. Moreover, we present detailed phenotypic information, including neuropsychological features, that contribute to the broad phenotypic spectrum of the syndrome. Comparison of the phenotype of both the microdeletion and SNV patients does not show differences of clinical importance, stressing that haploinsufficiency of KANSL1 is sufficient to cause the full KdVS phenotype.


Assuntos
Anormalidades Múltiplas/diagnóstico , Deficiência Intelectual/diagnóstico , Proteínas Nucleares/genética , Fenótipo , Polimorfismo de Nucleotídeo Único , Anormalidades Múltiplas/genética , Adolescente , Adulto , Criança , Deleção Cromossômica , Cromossomos Humanos Par 17/genética , Feminino , Humanos , Deficiência Intelectual/genética , Masculino , Pessoa de Meia-Idade
8.
Nat Neurosci ; 18(12): 1731-6, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26571461

RESUMO

The NONO protein has been characterized as an important transcriptional regulator in diverse cellular contexts. Here we show that loss of NONO function is a likely cause of human intellectual disability and that NONO-deficient mice have cognitive and affective deficits. Correspondingly, we find specific defects at inhibitory synapses, where NONO regulates synaptic transcription and gephyrin scaffold structure. Our data identify NONO as a possible neurodevelopmental disease gene and highlight the key role of the DBHS protein family in functional organization of GABAergic synapses.


Assuntos
Deficiência Intelectual/diagnóstico , Deficiência Intelectual/genética , Mutação/genética , Inibição Neural/genética , Proteínas Associadas à Matriz Nuclear/genética , Fatores de Transcrição de Octâmero/genética , Proteínas de Ligação a RNA/genética , Sinapses/genética , Adolescente , Animais , Encéfalo/patologia , Células Cultivadas , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Linhagem , Sinapses/patologia
9.
Am J Hum Genet ; 97(3): 475-82, 2015 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-26299364

RESUMO

Adams-Oliver syndrome (AOS) is a rare developmental disorder characterized by the presence of aplasia cutis congenita (ACC) of the scalp vertex and terminal limb-reduction defects. Cardiovascular anomalies are also frequently observed. Mutations in five genes have been identified as a cause for AOS prior to this report. Mutations in EOGT and DOCK6 cause autosomal-recessive AOS, whereas mutations in ARHGAP31, RBPJ, and NOTCH1 lead to autosomal-dominant AOS. Because RBPJ, NOTCH1, and EOGT are involved in NOTCH signaling, we hypothesized that mutations in other genes involved in this pathway might also be implicated in AOS pathogenesis. Using a candidate-gene-based approach, we prioritized DLL4, a critical NOTCH ligand, due to its essential role in vascular development in the context of cardiovascular features in AOS-affected individuals. Targeted resequencing of the DLL4 gene with a custom enrichment panel in 89 independent families resulted in the identification of seven mutations. A defect in DLL4 was also detected in two families via whole-exome or genome sequencing. In total, nine heterozygous mutations in DLL4 were identified, including two nonsense and seven missense variants, the latter encompassing four mutations that replace or create cysteine residues, which are most likely critical for maintaining structural integrity of the protein. Affected individuals with DLL4 mutations present with variable clinical expression with no emerging genotype-phenotype correlations. Our findings demonstrate that DLL4 mutations are an additional cause of autosomal-dominant AOS or isolated ACC and provide further evidence for a key role of NOTCH signaling in the etiology of this disorder.


Assuntos
Displasia Ectodérmica/genética , Displasia Ectodérmica/patologia , Peptídeos e Proteínas de Sinalização Intercelular/genética , Deformidades Congênitas dos Membros/genética , Deformidades Congênitas dos Membros/patologia , Mutação/genética , Dermatoses do Couro Cabeludo/congênito , Transdução de Sinais/genética , Sequência de Aminoácidos , Sequência de Bases , Heterozigoto , Humanos , Dados de Sequência Molecular , Linhagem , Receptores Notch/genética , Dermatoses do Couro Cabeludo/genética , Dermatoses do Couro Cabeludo/patologia , Análise de Sequência de DNA
10.
Hum Mutat ; 34(1): 237-47, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23033313

RESUMO

OFD1, now recognized as a ciliopathy, is characterized by malformations of the face, oral cavity and digits, and is transmitted as an X-linked condition with lethality in males. Mutations in OFD1 also cause X-linked Joubert syndrome (JBTS10) and Simpson-Golabi-Behmel syndrome type 2 (SGBS2). We have studied 55 sporadic and six familial cases of suspected OFD1. Comprehensive mutation analysis in OFD1 revealed mutations in 37 female patients from 30 families; 22 mutations have not been previously described including two heterozygous deletions spanning OFD1 and neighbouring genes. Analysis of clinical findings in patients with mutations revealed that oral features are the most reliable diagnostic criteria. A first, detailed evaluation of brain MRIs from seven patients with cognitive defects illustrated extensive variability with the complete brain phenotype consisting of complete agenesis of the corpus callosum, large single or multiple interhemispheric cysts, striking cortical infolding of gyri, ventriculomegaly, mild molar tooth malformation and moderate to severe cerebellar vermis hypoplasia. Although the OFD1 gene apparently escapes X-inactivation, skewed inactivation was observed in seven of 14 patients. The direction of skewing did not correlate with disease severity, reinforcing the hypothesis that additional factors contribute to the extensive intrafamilial variability.


Assuntos
Deleção de Genes , Mutação , Síndromes Orofaciodigitais/genética , Proteínas/genética , Adolescente , Processamento Alternativo/genética , Sequência de Bases , Encéfalo/metabolismo , Encéfalo/patologia , Criança , Análise Mutacional de DNA , Éxons/genética , Saúde da Família , Feminino , Estudos de Associação Genética/métodos , Humanos , Lactente , Íntrons/genética , Imagem por Ressonância Magnética , Masculino , Síndromes Orofaciodigitais/patologia , Linhagem , Inativação do Cromossomo X
11.
Hum Mutat ; 34(1): 111-21, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22829427

RESUMO

Autosomal recessive cutis laxa type I (ARCL type I) is characterized by generalized cutis laxa with pulmonary emphysema and/or vascular complications. Rarely, mutations can be identified in FBLN4 or FBLN5. Recently, LTBP4 mutations have been implicated in a similar phenotype. Studying FBLN4, FBLN5, and LTBP4 in 12 families with ARCL type I, we found bi-allelic FBLN5 mutations in two probands, whereas nine probands harbored biallelic mutations in LTBP4. FBLN5 and LTBP4 mutations cause a very similar phenotype associated with severe pulmonary emphysema, in the absence of vascular tortuosity or aneurysms. Gastrointestinal and genitourinary tract involvement seems to be more severe in patients with LTBP4 mutations. Functional studies showed that most premature termination mutations in LTBP4 result in severely reduced mRNA and protein levels. This correlated with increased transforming growth factor-beta (TGFß) activity. However, one mutation, c.4127dupC, escaped nonsense-mediated decay. The corresponding mutant protein (p.Arg1377Alafs(*) 27) showed reduced colocalization with fibronectin, leading to an abnormal morphology of microfibrils in fibroblast cultures, while retaining normal TGFß activity. We conclude that LTBP4 mutations cause disease through both loss of function and gain of function mechanisms.


Assuntos
Cútis Laxa/genética , Proteínas da Matriz Extracelular/genética , Proteínas de Ligação a TGF-beta Latente/genética , Mutação , Adolescente , Sequência de Bases , Western Blotting , Criança , Pré-Escolar , Consanguinidade , Cútis Laxa/complicações , Proteínas da Matriz Extracelular/metabolismo , Saúde da Família , Feminino , Expressão Gênica , Humanos , Lactente , Proteínas de Ligação a TGF-beta Latente/metabolismo , Masculino , Microscopia Eletrônica , Linhagem , Enfisema Pulmonar/complicações , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sequência de DNA , Pele/metabolismo , Pele/patologia , Pele/ultraestrutura , Adulto Jovem
12.
PLoS Genet ; 8(11): e1002945, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23144622

RESUMO

A homozygous mutational change in the Ataxia-Telangiectasia and RAD3 related (ATR) gene was previously reported in two related families displaying Seckel Syndrome (SS). Here, we provide the first identification of a Seckel Syndrome patient with mutations in ATRIP, the gene encoding ATR-Interacting Protein (ATRIP), the partner protein of ATR required for ATR stability and recruitment to the site of DNA damage. The patient has compound heterozygous mutations in ATRIP resulting in reduced ATRIP and ATR expression. A nonsense mutational change in one ATRIP allele results in a C-terminal truncated protein, which impairs ATR-ATRIP interaction; the other allele is abnormally spliced. We additionally describe two further unrelated patients native to the UK with the same novel, heterozygous mutations in ATR, which cause dramatically reduced ATR expression. All patient-derived cells showed defective DNA damage responses that can be attributed to impaired ATR-ATRIP function. Seckel Syndrome is characterised by microcephaly and growth delay, features also displayed by several related disorders including Majewski (microcephalic) osteodysplastic primordial dwarfism (MOPD) type II and Meier-Gorlin Syndrome (MGS). The identification of an ATRIP-deficient patient provides a novel genetic defect for Seckel Syndrome. Coupled with the identification of further ATR-deficient patients, our findings allow a spectrum of clinical features that can be ascribed to the ATR-ATRIP deficient sub-class of Seckel Syndrome. ATR-ATRIP patients are characterised by extremely severe microcephaly and growth delay, microtia (small ears), micrognathia (small and receding chin), and dental crowding. While aberrant bone development was mild in the original ATR-SS patient, some of the patients described here display skeletal abnormalities including, in one patient, small patellae, a feature characteristically observed in Meier-Gorlin Syndrome. Collectively, our analysis exposes an overlapping clinical manifestation between the disorders but allows an expanded spectrum of clinical features for ATR-ATRIP Seckel Syndrome to be defined.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal , Proteínas de Ciclo Celular , Proteínas de Ligação a DNA , Nanismo/genética , Transtornos do Crescimento , Micrognatismo , Proteínas Serina-Treonina Quinases , Proteínas Adaptadoras de Transdução de Sinal/deficiência , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas Mutadas de Ataxia Telangiectasia , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Códon sem Sentido , Microtia Congênita , Proteínas de Ligação a DNA/deficiência , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Nanismo/patologia , Orelha/anormalidades , Orelha/patologia , Feminino , Retardo do Crescimento Fetal/genética , Retardo do Crescimento Fetal/patologia , Regulação da Expressão Gênica , Transtornos do Crescimento/genética , Transtornos do Crescimento/patologia , Heterozigoto , Humanos , Masculino , Microcefalia/genética , Microcefalia/patologia , Micrognatismo/genética , Micrognatismo/patologia , Osteocondrodisplasias/genética , Osteocondrodisplasias/patologia , Patela/anormalidades , Patela/patologia , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Processamento de RNA , Transdução de Sinais/genética
13.
Am J Hum Genet ; 90(2): 321-30, 2012 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-22325361

RESUMO

Congenital stationary night blindness (CSNB) is a heterogeneous retinal disorder characterized by visual impairment under low light conditions. This disorder is due to a signal transmission defect from rod photoreceptors to adjacent bipolar cells in the retina. Two forms can be distinguished clinically, complete CSNB (cCSNB) or incomplete CSNB; the two forms are distinguished on the basis of the affected signaling pathway. Mutations in NYX, GRM6, and TRPM1, expressed in the outer plexiform layer (OPL) lead to disruption of the ON-bipolar cell response and have been seen in patients with cCSNB. Whole-exome sequencing in cCSNB patients lacking mutations in the known genes led to the identification of a homozygous missense mutation (c.1807C>T [p.His603Tyr]) in one consanguineous autosomal-recessive cCSNB family and a homozygous frameshift mutation in GPR179 (c.278delC [p.Pro93Glnfs(∗)57]) in a simplex male cCSNB patient. Additional screening with Sanger sequencing of 40 patients identified three other cCSNB patients harboring additional allelic mutations in GPR179. Although, immunhistological studies revealed Gpr179 in the OPL in wild-type mouse retina, Gpr179 did not colocalize with specific ON-bipolar markers. Interestingly, Gpr179 was highly concentrated in horizontal cells and Müller cell endfeet. The involvement of these cells in cCSNB and the specific function of GPR179 remain to be elucidated.


Assuntos
Exoma , Mutação , Miopia/genética , Cegueira Noturna/genética , Receptores Acoplados a Proteínas-G/genética , Alelos , Animais , Eletrorretinografia/métodos , Oftalmopatias Hereditárias , Feminino , Doenças Genéticas Ligadas ao Cromossomo X , Heterogeneidade Genética , Técnicas de Genotipagem/métodos , Heterozigoto , Homozigoto , Humanos , Masculino , Camundongos , Fenótipo , Polimorfismo de Nucleotídeo Único , Estrutura Terciária de Proteína , Proteoglicanas/genética , Receptores de Glutamato Metabotrópico/genética , Retina/anormalidades , Canais de Cátion TRPM/genética
14.
Invest Ophthalmol Vis Sci ; 52(10): 7432-40, 2011 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-21862650

RESUMO

PURPOSE: To identify the defective gene in the sex-linked, recessively inherited retinal dysplasia and degeneration (rdd) chicken and to search for the human equivalent disease. METHODS: Microsatellites from chicken chromosome Z were genotyped in 77 progeny of a carrier male (rdd/+) and an affected female (rdd/W), and candidate genes were sequenced. Retinal cross-sections from rdd and wild-type birds were analyzed by immunohistology. The human orthologous gene was screened in a panel of archival DNAs from 276 patients with retinitis pigmentosa (RP) or Leber congenital amaurosis (LCA) using melting curve analysis and DNA sequencing. RESULTS: The rdd locus was refined to an approximately 3-Mb region on chromosome Z. Sequence analysis identified a C→T change in the mpdz gene that created a premature stop codon (c.1372C→T, p.R458X), which segregated with the disease phenotype. As expected, the full-length mpdz protein was absent in rdd retinas, but in wild-type birds, it localized to the retinal outer limiting membrane, where it may have a role in the interactions between photoreceptors and Müller glia cells. The screen to identify the human equivalent disease found 10 heterozygous variants in the orthologous gene in patients with RP (three missense and two null alleles) and LCA (four missense and one null allele). CONCLUSIONS: These findings reveal that MPDZ is essential for normal development of the retina and may have a role in maintaining photoreceptor integrity. The identification of human mutations suggests that MPDZ plays a role in human retinal disease, but the precise nature of this role remains to be determined.


Assuntos
Proteínas de Transporte/genética , Modelos Animais de Doenças , Amaurose Congênita de Leber/genética , Mutação , Degeneração Retiniana/genética , Retinite Pigmentosa/genética , Alelos , Animais , Western Blotting , Galinhas , Feminino , Técnica Indireta de Fluorescência para Anticorpo , Genótipo , Humanos , Masculino , Microscopia Confocal , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sequência de DNA
15.
J Med Genet ; 48(4): 273-8, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21266384

RESUMO

BACKGROUND: Constitutional DICER1 mutations were recently reported to cause familial pleuropulmonary blastoma (PPB). AIM: To investigate the contribution and phenotypic spectrum of constitutional and somatic DICER1 mutations to cancer. METHODS AND RESULTS: The authors sequenced DICER1 in constitutional DNA from 823 unrelated patients with a variety of tumours and in 781 cancer cell lines. Constitutional DICER1 mutations were identified in 19 families including 11/14 with PPB, 2/3 with cystic nephroma, 4/7 with ovarian Sertoli-Leydig-type tumours, 1/243 with Wilms tumour (this patient also had a Sertoli-Leydig tumour), 1/1 with intraocular medulloepithelioma (this patient also had PPB), 1/86 with medulloblastoma/infratentorial primitive neuroectodermal tumour, and 1/172 with germ cell tumour. The inheritance was investigated in 17 families. DICER1 mutations were identified in 25 relatives: 17 were unaffected, one mother had ovarian Sertoli-Leydig tumour, one half-sibling had cystic nephroma, and six relatives had non-toxic thyroid cysts/goitre. Analysis of eight tumours from DICER1 mutation-positive patients showed universal retention of the wild-type allele. DICER1 truncating mutations were identified in 4/781 cancer cell lines; all were in microsatellite unstable lines and therefore unlikely to be driver mutations. CONCLUSION: Constitutional DICER1 haploinsufficiency predisposes to a broad range of tumours, making a substantial contribution to PPB, cystic nephroma and ovarian Sertoli-Leydig tumours, but a smaller contribution to other tumours. Most mutation carriers are unaffected, indicating that tumour risk is modest. The authors define the clinical contexts in which DICER1 mutation testing should be considered, the associated tumour risks, and the implications for at-risk individuals. They have termed this condition 'DICER1 syndrome'. ACCESSION NUMBERS: The cDNA Genbank accession number for the DICER1 sequence reported in this paper is NM_030621.2.


Assuntos
RNA Helicases DEAD-box/genética , Predisposição Genética para Doença , Neoplasias/genética , Ribonuclease III/genética , Linhagem Celular Tumoral , Mutação em Linhagem Germinativa , Haploinsuficiência , Humanos , Dados de Sequência Molecular , Neoplasias/diagnóstico , Análise de Sequência de DNA , Síndrome
16.
Eur J Med Genet ; 54(3): 301-5, 2011 May-Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21199695

RESUMO

Ulnar Mammary syndrome (UMS) is an autosomal disorder caused by haploinsufficiency of the TBX3 gene. There is marked intrafamilial variation in expression of the syndrome. We present one three generation family in which the proband has absence of the right ulna and third, fourth and fifth rays in her right hand. Her mother and maternal grandmother have more subtle anomalies while all have a similar facial appearance with a broad nasal tip, a broad jaw, a prominent chin and a tongue frenulum. They have a single base pair insertion (c. 992dup) in TBX3. We compare faces from the handful of published UMS patients which include photographs, this family and four other cases with TBX3 mutations. All have similarities in appearance which we suggest could alert clinicians to the possibility of a TBX3 mutation if individuals present with more subtle features of UMS such as postaxial polydactyly, isolated 5th finger anomalies, delayed puberty in males, breast hypoplasia or short stature with or without growth hormone deficiency.


Assuntos
Anormalidades Múltiplas/patologia , Doenças Mamárias/patologia , Face/anormalidades , Ulna/anormalidades , Anormalidades Múltiplas/genética , Adulto , Criança , Pré-Escolar , Saúde da Família , Feminino , Dedos/anormalidades , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Mutação , Linhagem , Síndrome , Proteínas com Domínio T/genética , Adulto Jovem
18.
J Clin Invest ; 119(11): 3301-10, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19855134

RESUMO

Aortic arch artery patterning defects account for approximately 20% of congenital cardiovascular malformations and are observed frequently in velocardiofacial syndrome (VCFS). In the current study, we screened for chromosome rearrangements in patients suspected of VCFS, but who lacked a 22q11 deletion or TBX1 mutation. One individual displayed hemizygous CHD7, which encodes a chromodomain protein. CHD7 haploinsufficiency is the major cause of coloboma, heart defect, atresia choanae, retarded growth and development, genital hypoplasia, and ear anomalies/deafness (CHARGE) syndrome, but this patient lacked the major diagnostic features of coloboma and choanal atresia. Because a subset of CHARGE cases also display 22q11 deletions, we explored the embryological relationship between CHARGE and VCSF using mouse models. The hallmark of Tbx1 haploinsufficiency is hypo/aplasia of the fourth pharyngeal arch artery (PAA) at E10.5. Identical malformations were observed in Chd7 heterozygotes, with resulting aortic arch interruption at later stages. Other than Tbx1, Chd7 is the only gene reported to affect fourth PAA development by haploinsufficiency. Moreover, Tbx1+/-;Chd7+/- double heterozygotes demonstrated a synergistic interaction during fourth PAA, thymus, and ear morphogenesis. We could not rescue PAA morphogenesis by restoring neural crest Chd7 expression. Rather, biallelic expression of Chd7 and Tbx1 in the pharyngeal ectoderm was required for normal PAA development.


Assuntos
Alelos , Aorta Torácica/embriologia , Proteínas de Ligação a DNA/metabolismo , Ectoderma/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Proteínas com Domínio T/metabolismo , Animais , Hibridização Genômica Comparativa , Proteínas de Ligação a DNA/genética , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteínas com Domínio T/genética
19.
Hum Genet ; 126(6): 791-803, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19685247

RESUMO

Mutations in the transcription factor encoding TFAP2A gene underlie branchio-oculo-facial syndrome (BOFS), a rare dominant disorder characterized by distinctive craniofacial, ocular, ectodermal and renal anomalies. To elucidate the range of ocular phenotypes caused by mutations in TFAP2A, we took three approaches. First, we screened a cohort of 37 highly selected individuals with severe ocular anomalies plus variable defects associated with BOFS for mutations or deletions in TFAP2A. We identified one individual with a de novo TFAP2A four amino acid deletion, a second individual with two non-synonymous variations in an alternative splice isoform TFAP2A2, and a sibling-pair with a paternally inherited whole gene deletion with variable phenotypic expression. Second, we determined that TFAP2A is expressed in the lens, neural retina, nasal process, and epithelial lining of the oral cavity and palatal shelves of human and mouse embryos--sites consistent with the phenotype observed in patients with BOFS. Third, we used zebrafish to examine how partial abrogation of the fish ortholog of TFAP2A affects the penetrance and expressivity of ocular phenotypes due to mutations in genes encoding bmp4 or tcf7l1a. In both cases, we observed synthetic, enhanced ocular phenotypes including coloboma and anophthalmia when tfap2a is knocked down in embryos with bmp4 or tcf7l1a mutations. These results reveal that mutations in TFAP2A are associated with a wide range of eye phenotypes and that hypomorphic tfap2a mutations can increase the risk of developmental defects arising from mutations at other loci.


Assuntos
Anormalidades do Olho/genética , Olho/embriologia , Retina/anormalidades , Fator de Transcrição AP-2/genética , Adulto , Animais , Síndrome Brânquio-Otorrenal/genética , Pré-Escolar , Feminino , Deleção de Genes , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Morfogênese/genética , Mutação , Peixe-Zebra , Proteínas de Peixe-Zebra/genética
20.
Hum Mutat ; 30(5): E618-28, 2009 May.
Artigo em Inglês | MEDLINE | ID: mdl-19309688

RESUMO

The X-linked dominant trait focal dermal hypoplasia (FDH, Goltz syndrome) is a developmental defect with focal distribution of affected tissues due to a block of Wnt signal transmission from cells carrying a detrimental PORCN mutation on an active X-chromosome. Molecular characterization of 24 unrelated patients from different ethnic backgrounds revealed 23 different mutations of the PORCN gene in Xp11.23. Three were microdeletions eliminating PORCN and encompassing neighboring genes such as EBP, the gene associated with Conradi-Hünermann-Happle syndrome (CDPX2). 12/24 patients carried nonsense mutations resulting in loss of function. In one case a canonical splice acceptor site was mutated, and 8 missense mutations exchanged highly conserved amino acids. FDH patients overcome the consequences of potentially lethal X-chromosomal mutations by extreme skewing of X-chromosome inactivation in females, enabling transmission of the trait in families, or by postzygotic mosaicism both in male and female individuals. Molecular characterization of the PORCN mutations in cases diagnosed as Goltz syndrome is particularly relevant for genetic counseling of patients and their families since no functional diagnostic test is available and carriers of the mutation might otherwise be overlooked due to considerable phenotypic variability associated with the mosaic status.


Assuntos
Hipoplasia Dérmica Focal/genética , Hipoplasia Dérmica Focal/patologia , Proteínas de Membrana/genética , Mutação/genética , Aciltransferases , Adolescente , Adulto , Sequência de Aminoácidos , Sequência de Bases , Criança , Pré-Escolar , Análise Mutacional de DNA , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Proteínas de Membrana/química , Dados de Sequência Molecular , Isoformas de Proteínas/química , Isoformas de Proteínas/genética
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