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2.
Genome Med ; 11(1): 12, 2019 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-30819258

RESUMO

BACKGROUND: Neurodevelopmental disorders are genetically and phenotypically heterogeneous encompassing developmental delay (DD), intellectual disability (ID), autism spectrum disorders (ASDs), structural brain abnormalities, and neurological manifestations with variants in a large number of genes (hundreds) associated. To date, a few de novo mutations potentially disrupting TCF20 function in patients with ID, ASD, and hypotonia have been reported. TCF20 encodes a transcriptional co-regulator structurally related to RAI1, the dosage-sensitive gene responsible for Smith-Magenis syndrome (deletion/haploinsufficiency) and Potocki-Lupski syndrome (duplication/triplosensitivity). METHODS: Genome-wide analyses by exome sequencing (ES) and chromosomal microarray analysis (CMA) identified individuals with heterozygous, likely damaging, loss-of-function alleles in TCF20. We implemented further molecular and clinical analyses to determine the inheritance of the pathogenic variant alleles and studied the spectrum of phenotypes. RESULTS: We report 25 unique inactivating single nucleotide variants/indels (1 missense, 1 canonical splice-site variant, 18 frameshift, and 5 nonsense) and 4 deletions of TCF20. The pathogenic variants were detected in 32 patients and 4 affected parents from 31 unrelated families. Among cases with available parental samples, the variants were de novo in 20 instances and inherited from 4 symptomatic parents in 5, including in one set of monozygotic twins. Two pathogenic loss-of-function variants were recurrent in unrelated families. Patients presented with a phenotype characterized by developmental delay, intellectual disability, hypotonia, variable dysmorphic features, movement disorders, and sleep disturbances. CONCLUSIONS: TCF20 pathogenic variants are associated with a novel syndrome manifesting clinical characteristics similar to those observed in Smith-Magenis syndrome. Together with previously described cases, the clinical entity of TCF20-associated neurodevelopmental disorders (TAND) emerges from a genotype-driven perspective.


Assuntos
Anormalidades Craniofaciais/genética , Deficiências do Desenvolvimento/genética , Mutação INDEL , Deficiência Intelectual/genética , Hipotonia Muscular/genética , Síndrome de Smith-Magenis/genética , Fatores de Transcrição/genética , Adolescente , Criança , Pré-Escolar , Anormalidades Craniofaciais/patologia , Deficiências do Desenvolvimento/patologia , Feminino , Humanos , Lactente , Deficiência Intelectual/patologia , Masculino , Hipotonia Muscular/patologia , Síndrome de Smith-Magenis/patologia , Fatores de Transcrição/metabolismo , Adulto Jovem
3.
Genome Res ; 29(2): 159-170, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30587507

RESUMO

Mutations that perturb normal pre-mRNA splicing are significant contributors to human disease. We used exome sequencing data from 7833 probands with developmental disorders (DDs) and their unaffected parents, as well as more than 60,000 aggregated exomes from the Exome Aggregation Consortium, to investigate selection around the splice sites and quantify the contribution of splicing mutations to DDs. Patterns of purifying selection, a deficit of variants in highly constrained genes in healthy subjects, and excess de novo mutations in patients highlighted particular positions within and around the consensus splice site of greater functional relevance. By using mutational burden analyses in this large cohort of proband-parent trios, we could estimate in an unbiased manner the relative contributions of mutations at canonical dinucleotides (73%) and flanking noncanonical positions (27%), and calculate the positive predictive value of pathogenicity for different classes of mutations. We identified 18 patients with likely diagnostic de novo mutations in dominant DD-associated genes at noncanonical positions in splice sites. We estimate 35%-40% of pathogenic variants in noncanonical splice site positions are missing from public databases.


Assuntos
Deficiências do Desenvolvimento/genética , Mutação , Sítios de Splice de RNA , Exoma , Humanos , Sequenciamento Completo do Exoma
4.
Gene ; 685: 50-54, 2018 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-30393191

RESUMO

The SRPX2 gene (Sushi-repeat-containing protein, X-linked, 2, OMIM*300642), located on Xq22.1, encodes a secreted protein that is highly expressed in neurons of cerebral cortex. SRPX2 was first implicated in neurodevelopment, learning and rolandic seizure when two patients with potentially pathogenic variants, c.980A>G (p.Asn327Ser) and c.215A>C (p.Tyr72Ser), in SRPX2 gene were identified. Subsequent experimental studies demonstrated that SRPX2 is needed for vocalization and synapse formation in mice, and that both silencing SRPX2 and injecting (p.Asn327Ser) in mouse models results in alteration in neuronal migration in cerebral cortex and epilepsy. A number of studies demonstrated that SRPX2 interacts with FOXP2 (Foxhead box protein P2), a gene responsible for speech and language disorder, and that FoxP2 controls timing and level of expression of SRPX2. Despite the supportive evidence for the role of SRPX2 in speech and language development and disorders, there are questions over its definitive association with neurodevelopmental disorders and epilepsy. In this paper, the role of SRPX2 as one in a network of many genes involved in speech and language is discussed. The goal of this paper is to examine the role of SRPX2 variants through describing two patients with potentially pathogenic variants in SRPX2, c.751G>C (p.Ala251Pro) and c.762G>T (p.Lys254Asn) presenting with language and motor delay, intellectual disability as well as congenital anomalies. We explore the contribution of SRPX2 variants to clinical phenotype in our patients and conclude that these variants at least partially explain the phenotype. Further studies are necessary to establish and confirm the association between SRPX2 and neurodevelopment particularly speech and language development.

5.
Int J Mol Sci ; 19(8)2018 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-30071673

RESUMO

Lymphedema is characterized by chronic swelling of any body part caused by malfunctioning or obstruction in the lymphatic system. Primary lymphedema is often considered genetic in origin. VEGFC, which is a gene encoding the ligand for the vascular endothelial growth factor receptor 3 (VEGFR3/FLT4) and important for lymph vessel development during lymphangiogenesis, has been associated with a specific subtype of primary lymphedema. Through Sanger sequencing of a proband with bilateral congenital pedal edema resembling Milroy disease, we identified a novel mutation (NM_005429.2; c.361+5G>A) in VEGFC. The mutation induced skipping of exon 2 of VEGFC resulting in a frameshift and the introduction of a premature stop codon (p.Ala50ValfsTer18). The mutation leads to a loss of the entire VEGF-homology domain and the C-terminus. Expression of this Vegfc variant in the zebrafish floorplate showed that the splice-site variant significantly reduces the biological activity of the protein. Our findings confirm that the splice-site variant, c.361+5G>A, causes the primary lymphedema phenotype in the proband. We examine the mutations and clinical phenotypes of the previously reported cases to review the current knowledge in this area.


Assuntos
Artrogripose/genética , Fissura Palatina/genética , Pé Torto Equinovaro/genética , Mutação da Fase de Leitura , Deformidades Congênitas da Mão/genética , Processamento de RNA/genética , Fator C de Crescimento do Endotélio Vascular/genética , Animais , Animais Geneticamente Modificados/genética , Animais Geneticamente Modificados/metabolismo , Artrogripose/metabolismo , Artrogripose/patologia , Pré-Escolar , Fissura Palatina/metabolismo , Fissura Palatina/patologia , Pé Torto Equinovaro/metabolismo , Pé Torto Equinovaro/patologia , Feminino , Deformidades Congênitas da Mão/metabolismo , Deformidades Congênitas da Mão/patologia , Humanos , Lactente , Recém-Nascido , Masculino , Domínios Proteicos , Fator C de Crescimento do Endotélio Vascular/metabolismo , Peixe-Zebra/genética , Peixe-Zebra/metabolismo
6.
Lancet Gastroenterol Hepatol ; 3(7): 489-498, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29706558

RESUMO

BACKGROUND: Germline pathogenic variants in the E-cadherin gene (CDH1) are strongly associated with the development of hereditary diffuse gastric cancer. There is a paucity of data to guide risk assessment and management of families with hereditary diffuse gastric cancer that do not carry a CDH1 pathogenic variant, making it difficult to make informed decisions about surveillance and risk-reducing surgery. We aimed to identify new candidate genes associated with predisposition to hereditary diffuse gastric cancer in affected families without pathogenic CDH1 variants. METHODS: We did whole-exome sequencing on DNA extracted from the blood of 39 individuals (28 individuals diagnosed with hereditary diffuse gastric cancer and 11 unaffected first-degree relatives) in 22 families without pathogenic CDH1 variants. Genes with loss-of-function variants were prioritised using gene-interaction analysis to identify clusters of genes that could be involved in predisposition to hereditary diffuse gastric cancer. FINDINGS: Protein-affecting germline variants were identified in probands from six families with hereditary diffuse gastric cancer; variants were found in genes known to predispose to cancer and in lesser-studied DNA repair genes. A frameshift deletion in PALB2 was found in one member of a family with a history of gastric and breast cancer. Two different MSH2 variants were identified in two unrelated affected individuals, including one frameshift insertion and one previously described start-codon loss. One family had a unique combination of variants in the DNA repair genes ATR and NBN. Two variants in the DNA repair gene RECQL5 were identified in two unrelated families: one missense variant and a splice-acceptor variant. INTERPRETATION: The results of this study suggest a role for the known cancer predisposition gene PALB2 in families with hereditary diffuse gastric cancer and no detected pathogenic CDH1 variants. We also identified new candidate genes associated with disease risk in these families. FUNDING: UK Medical Research Council (Sackler programme), European Research Council under the European Union's Seventh Framework Programme (2007-13), National Institute for Health Research Cambridge Biomedical Research Centre, Experimental Cancer Medicine Centres, and Cancer Research UK.

7.
J Med Genet ; 55(6): 384-394, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29386252

RESUMO

BACKGROUND: Germline pathogenic variants in SDHB/SDHC/SDHD are the most frequent causes of inherited phaeochromocytomas/paragangliomas. Insufficient information regarding penetrance and phenotypic variability hinders optimum management of mutation carriers. We estimate penetrance for symptomatic tumours and elucidate genotype-phenotype correlations in a large cohort of SDHB/SDHC/SDHD mutation carriers. METHODS: A retrospective survey of 1832 individuals referred for genetic testing due to a personal or family history of phaeochromocytoma/paraganglioma. 876 patients (401 previously reported) had a germline mutation in SDHB/SDHC/SDHD (n=673/43/160). Tumour risks were correlated with in silico structural prediction analyses. RESULTS: Tumour risks analysis provided novel penetrance estimates and genotype-phenotype correlations. In addition to tumour type susceptibility differences for individual genes, we confirmed that the SDHD:p.Pro81Leu mutation has a distinct phenotype and identified increased age-related tumour risks with highly destabilising SDHB missense mutations. By Kaplan-Meier analysis, the penetrance (cumulative risk of clinically apparent tumours) in SDHB and (paternally inherited) SDHD mutation-positive non-probands (n=371/67 with detailed clinical information) by age 60 years was 21.8% (95% CI 15.2% to 27.9%) and 43.2% (95% CI 25.4% to 56.7%), respectively. Risk of malignant disease at age 60 years in non-proband SDHB mutation carriers was 4.2%(95% CI 1.1% to 7.2%). With retrospective cohort analysis to adjust for ascertainment, cumulative tumour risks for SDHB mutation carriers at ages 60 years and 80 years were 23.9% (95% CI 20.9% to 27.4%) and 30.6% (95% CI 26.8% to 34.7%). CONCLUSIONS: Overall risks of clinically apparent tumours for SDHB mutation carriers are substantially lower than initially estimated and will improve counselling of affected families. Specific genotype-tumour risk associations provides a basis for novel investigative strategies into succinate dehydrogenase-related mechanisms of tumourigenesis and the development of personalised management for SDHB/SDHC/SDHD mutation carriers.

8.
J Med Genet ; 55(4): 233-239, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29358271

RESUMO

Background Irish Travellers are an endogamous, nomadic, ethnic minority population mostly resident on the island of Ireland with smaller populations in Europe and the USA. High levels of consanguinity result in many rare autosomal recessive disorders. Due to founder effects and endogamy, most recessive disorders are caused by specific homozygous mutations unique to this population. Key clinicians and scientists with experience in managing rare disorders seen in this population have developed a de facto advisory service on differential diagnoses to consider when faced with specific clinical scenarios. Objective(s) To catalogue all known inherited disorders found in the Irish Traveller population. Methods We performed detailed literature and database searches to identify relevant publications and the disease mutations of known genetic disorders found in Irish Travellers. Results We identified 104 genetic disorders: 90 inherited in an autosomal recessive manner; 13 autosomal dominant and one a recurring chromosomal duplication. Conclusion We have collated our experience of inherited disorders found in the Irish Traveller population to make it publically available through this publication to facilitate a targeted genetic approach to diagnostics in this ethnic group.

10.
Am J Hum Genet ; 100(1): 138-150, 2017 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-28017370

RESUMO

Early B cell factor 3 (EBF3) is an atypical transcription factor that is thought to influence the laminar formation of the cerebral cortex. Here, we report that de novo mutations in EBF3 cause a complex neurodevelopmental syndrome. The mutations were identified in two large-scale sequencing projects: the UK Deciphering Developmental Disorders (DDD) study and the Canadian Clinical Assessment of the Utility of Sequencing and Evaluation as a Service (CAUSES) study. The core phenotype includes moderate to severe intellectual disability, and many individuals exhibit cerebellar ataxia, subtle facial dysmorphism, strabismus, and vesicoureteric reflux, suggesting that EBF3 has a widespread developmental role. Pathogenic de novo variants identified in EBF3 include multiple loss-of-function and missense mutations. Structural modeling suggested that the missense mutations affect DNA binding. Functional analysis of mutant proteins with missense substitutions revealed reduced transcriptional activities and abilities to form heterodimers with wild-type EBF3. We conclude that EBF3, a transcription factor previously unknown to be associated with human disease, is important for brain and other organ development and warrants further investigation.


Assuntos
Mutação , Transtornos do Neurodesenvolvimento/genética , Fatores de Transcrição/genética , Adolescente , Idade de Início , Ataxia/genética , Canadá , Criança , DNA/metabolismo , Deficiências do Desenvolvimento/genética , Face/anormalidades , Feminino , Humanos , Lactente , Recém-Nascido , Deficiência Intelectual/genética , Masculino , Mutação de Sentido Incorreto/genética , Estrabismo/genética , Síndrome , Fatores de Transcrição/metabolismo , Reino Unido
11.
Am J Med Genet A ; 170(11): 2835-2846, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27667800

RESUMO

KBG syndrome is characterized by short stature, distinctive facial features, and developmental/cognitive delay and is caused by mutations in ANKRD11, one of the ankyrin repeat-containing cofactors. We describe 32 KBG patients aged 2-47 years from 27 families ascertained via two pathways: targeted ANKRD11 sequencing (TS) in a group who had a clinical diagnosis of KBG and whole exome sequencing (ES) in a second group in whom the diagnosis was unknown. Speech delay and learning difficulties were almost universal and variable behavioral problems frequent. Macrodontia of permanent upper central incisors was seen in 85%. Other clinical features included short stature, conductive hearing loss, recurrent middle ear infection, palatal abnormalities, and feeding difficulties. We recognized a new feature of a wide anterior fontanelle with delayed closure in 22%. The subtle facial features of KBG syndrome were recognizable in half the patients. We identified 20 ANKRD11 mutations (18 novel: all truncating) confirmed by Sanger sequencing in 32 patients. Comparison of the two ascertainment groups demonstrated that facial/other typical features were more subtle in the ES group. There were no conclusive phenotype-genotype correlations. Our findings suggest that mutation of ANKRD11 is a common Mendelian cause of developmental delay. Affected patients may not show the characteristic KBG phenotype and the diagnosis is therefore easily missed. We propose updated diagnostic criteria/clinical recommendations for KBG syndrome and suggest that inclusion of ANKRD11 will increase the utility of gene panels designed to investigate developmental delay. © 2016 The Authors. American Journal of Medical Genetics Part A Published by Wiley Periodicals, Inc.


Assuntos
Anormalidades Múltiplas/diagnóstico , Anormalidades Múltiplas/genética , Doenças do Desenvolvimento Ósseo/diagnóstico , Doenças do Desenvolvimento Ósseo/genética , Estudos de Associação Genética , Predisposição Genética para Doença , Deficiência Intelectual/diagnóstico , Deficiência Intelectual/genética , Anormalidades Dentárias/diagnóstico , Anormalidades Dentárias/genética , Deleção Cromossômica , Cromossomos Humanos Par 16 , Hibridização Genômica Comparativa , Facies , Feminino , Humanos , Masculino , Fenótipo , Proteínas Repressoras/genética
12.
J Med Genet ; 53(3): 152-62, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26543203

RESUMO

BACKGROUND: SOX11 is a transcription factor proposed to play a role in brain development. The relevance of SOX11 to human developmental disorders was suggested by a recent report of SOX11 mutations in two patients with Coffin-Siris syndrome. Here we further investigate the role of SOX11 variants in neurodevelopmental disorders. METHODS: We used array based comparative genomic hybridisation and trio exome sequencing to identify children with intellectual disability who have deletions or de novo point mutations disrupting SOX11. The pathogenicity of the SOX11 mutations was assessed using an in vitro gene expression reporter system. Loss-of-function experiments were performed in xenopus by knockdown of Sox11 expression. RESULTS: We identified seven individuals with chromosome 2p25 deletions involving SOX11. Trio exome sequencing identified three de novo SOX11 variants, two missense (p.K50N; p.P120H) and one nonsense (p.C29*). The biological consequences of the missense mutations were assessed using an in vitro gene expression system. These individuals had microcephaly, developmental delay and shared dysmorphic features compatible with mild Coffin-Siris syndrome. To further investigate the function of SOX11, we knocked down the orthologous gene in xenopus. Morphants had significant reduction in head size compared with controls. This suggests that SOX11 loss of function can be associated with microcephaly. CONCLUSIONS: We thus propose that SOX11 deletion or mutation can present with a Coffin-Siris phenotype.


Assuntos
Anormalidades Múltiplas/genética , Face/anormalidades , Deformidades Congênitas da Mão/genética , Deficiência Intelectual/genética , Micrognatismo/genética , Pescoço/anormalidades , Transtornos do Neurodesenvolvimento/genética , Fatores de Transcrição SOXC/genética , Deleção de Sequência , Anormalidades Múltiplas/fisiopatologia , Adolescente , Adulto , Animais , Criança , Pré-Escolar , Face/fisiopatologia , Feminino , Técnicas de Silenciamento de Genes , Deformidades Congênitas da Mão/fisiopatologia , Humanos , Deficiência Intelectual/fisiopatologia , Masculino , Microcefalia , Micrognatismo/fisiopatologia , Pescoço/fisiopatologia , Transtornos do Neurodesenvolvimento/fisiopatologia , Xenopus
13.
Cancer Epidemiol Biomarkers Prev ; 24(9): 1373-80, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26082403

RESUMO

BACKGROUND: Randomized controlled trials have demonstrated significant reductions in colorectal cancer incidence and mortality associated with polypectomy. However, little is known about whether polypectomy is effective at reducing colorectal cancer risk in routine clinical practice. The aim of this investigation was to quantify colorectal cancer risk following polypectomy in a large prospective population-based cohort study. METHODS: Patients with incident colorectal polyps between 2000 and 2005 in Northern Ireland were identified via electronic pathology reports received to the Northern Ireland Cancer Registry. Patients were matched to the Northern Ireland Cancer Registry to detect colorectal cancer and deaths up to December 31, 2010. Colorectal cancer standardized incidence ratios (SIR) were calculated and Cox proportional hazards modeling applied to determine colorectal cancer risk. RESULTS: During 44,724 person-years of follow-up, 193 colorectal cancer cases were diagnosed among 6,972 adenoma patients, representing an annual progression rate of 0.43%. Colorectal cancer risk was significantly elevated in patients who had an adenoma removed (SIR, 2.85; 95% CI, 2.61-3.25) compared with the general population. Male sex, older age, rectal site, and villous architecture were associated with an increased colorectal cancer risk in adenoma patients. Further analysis suggested that not having a full colonoscopy performed at, or following, incident polypectomy contributed to the excess colorectal cancer risk. CONCLUSIONS: Colorectal cancer risk was elevated in individuals following polypectomy for adenoma, outside of screening programs. IMPACT: This finding emphasizes the need for full colonoscopy and adenoma clearance, and appropriate surveillance, after endoscopic diagnosis of adenoma.


Assuntos
Adenoma/cirurgia , Neoplasias do Colo/epidemiologia , Neoplasias do Colo/cirurgia , Pólipos do Colo/cirurgia , Neoplasias Retais/epidemiologia , Neoplasias Retais/cirurgia , Adenoma/patologia , Adolescente , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Neoplasias do Colo/patologia , Pólipos do Colo/patologia , Colonoscopia , Feminino , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Irlanda do Norte/epidemiologia , Modelos de Riscos Proporcionais , Estudos Prospectivos , Neoplasias Retais/patologia , Fatores de Risco , Fatores Sexuais , Adulto Jovem
14.
Ophthalmic Genet ; 36(1): 86-8, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24020716

RESUMO

Non-syndromic familial thoracic aortic aneurysms and dissections (TAAD) are inherited in an autosomal dominant manner. We report a missense mutation in the smooth muscle α-actin (ACTA2; MIM*102620) gene in a 3 generational family from Northern Ireland in which iris flocculi were an ocular marker of the disease.


Assuntos
Actinas/genética , Aneurisma da Aorta Torácica/genética , Cistos/genética , Predisposição Genética para Doença , Doenças da Íris/genética , Mutação de Sentido Incorreto , Adulto , Aneurisma da Aorta Torácica/cirurgia , Biomarcadores , Cistos/diagnóstico , Análise Mutacional de DNA , Feminino , Humanos , Doenças da Íris/diagnóstico , Masculino , Pessoa de Meia-Idade , Linhagem , Tomografia de Coerência Óptica
15.
Am J Med Genet A ; 161A(12): 2972-80, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24214728

RESUMO

Weaver syndrome, first described in 1974, is characterized by tall stature, a typical facial appearance, and variable intellectual disability. In 2011, mutations in the histone methyltransferase, EZH2, were shown to cause Weaver syndrome. To date, we have identified 48 individuals with EZH2 mutations. The mutations were primarily missense mutations occurring throughout the gene, with some clustering in the SET domain (12/48). Truncating mutations were uncommon (4/48) and only identified in the final exon, after the SET domain. Through analyses of clinical data and facial photographs of EZH2 mutation-positive individuals, we have shown that the facial features can be subtle and the clinical diagnosis of Weaver syndrome is thus challenging, especially in older individuals. However, tall stature is very common, reported in >90% of affected individuals. Intellectual disability is also common, present in ~80%, but is highly variable and frequently mild. Additional clinical features which may help in stratifying individuals to EZH2 mutation testing include camptodactyly, soft, doughy skin, umbilical hernia, and a low, hoarse cry. Considerable phenotypic overlap between Sotos and Weaver syndromes is also evident. The identification of an EZH2 mutation can therefore provide an objective means of confirming a subtle presentation of Weaver syndrome and/or distinguishing Weaver and Sotos syndromes. As mutation testing becomes increasingly accessible and larger numbers of EZH2 mutation-positive individuals are identified, knowledge of the clinical spectrum and prognostic implications of EZH2 mutations should improve.


Assuntos
Anormalidades Múltiplas/genética , Hipotireoidismo Congênito/genética , Anormalidades Craniofaciais/genética , Transtornos do Crescimento/genética , Deformidades Congênitas da Mão/genética , Deficiência Intelectual/genética , Complexo Repressor Polycomb 2/genética , Anormalidades Múltiplas/fisiopatologia , Adolescente , Criança , Pré-Escolar , Deleção Cromossômica , Hipotireoidismo Congênito/complicações , Hipotireoidismo Congênito/fisiopatologia , Anormalidades Craniofaciais/complicações , Anormalidades Craniofaciais/fisiopatologia , Deficiências do Desenvolvimento , Proteína Potenciadora do Homólogo 2 de Zeste , Feminino , Transtornos do Crescimento/complicações , Transtornos do Crescimento/fisiopatologia , Deformidades Congênitas da Mão/complicações , Deformidades Congênitas da Mão/fisiopatologia , Humanos , Deficiência Intelectual/complicações , Deficiência Intelectual/fisiopatologia , Masculino , Mutação , Fenótipo , Síndrome de Sotos/genética , Síndrome de Sotos/fisiopatologia
16.
BMC Med Genet ; 14: 48, 2013 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-23621912

RESUMO

BACKGROUND: COL11A1 is a large complex gene around 250 kb in length and consisting of 68 exons. Pathogenic mutations in the gene can result in Stickler syndrome, Marshall syndrome or Fibrochondrogenesis. Many of the mutations resulting in either Stickler or Marshall syndrome alter splice sites and result in exon skipping, which because of the exon structure of collagen genes usually leaves the message in-frame. The mutant protein then exerts a dominant negative effect as it co-assembles with other collagen gene products. To date only one large deletion of 40 kb in the COL11A1, which was detected by RT-PCR, has been characterized. However, commonly used screening protocols, utilizing genomic amplification and exon sequencing, are unlikely to detect such large deletions. Consequently the frequency of this type of mutation is unknown. CASE PRESENTATIONS: We have used Multiplex Ligation-Dependent Probe Amplification (MLPA) in conjunction with exon amplification and sequencing, to analyze patients with clinical features of Stickler syndrome, and have detected six novel deletions that were not found by exon sequencing alone. CONCLUSION: Exon deletions appear to represent a significant proportion of type 2 Stickler syndrome. This observation was previously unknown and so diagnostic screening of COL11A1 should include assays capable of detecting both large and small deletions, in addition to exon sequencing.


Assuntos
Colágeno Tipo XI/genética , Doenças do Tecido Conjuntivo/genética , Deleção de Genes , Reação em Cadeia da Polimerase Multiplex/métodos , Descolamento do Vítreo/genética , Adolescente , Adulto , Pré-Escolar , Colágeno Tipo XI/deficiência , Doenças do Tecido Conjuntivo/diagnóstico , Éxons , Feminino , Frequência do Gene , Humanos , Lactente , Masculino , Mutação , Processamento de RNA , Análise de Sequência de DNA , Descolamento do Vítreo/diagnóstico
17.
Am J Med Genet A ; 158A(5): 1102-10, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22495892

RESUMO

De novo heterozygous mutations in HRAS cause Costello syndrome (CS), a condition with high mortality and morbidity in infancy and early childhood due to cardiac, respiratory, and muscular complications. HRAS mutations predicting p.Gly12Val, p.Gly12Asp, and p.Gly12Cys substitutions have been associated with severe, lethal, CS. We report on molecular, clinical, and pathological findings in patients with mutations predicting HRAS p.Gly12Val that were identified in our clinical molecular genetic testing service. Such mutations were identified in four patients. Remarkably, three were deletion/insertion mutations affecting coding nucleotides 35 and 36. All patients died within 6 postnatal weeks, providing further evidence that p.Gly12Val mutations predict a very poor prognosis. High birth weight, polyhydramnios (and premature birth), cardiac hypertrophy, respiratory distress, muscle weakness, and postnatal growth failure were present. Dysmorphism was subtle or non-specific, with edema, coarsened facial features, prominent forehead, depressed nasal bridge, anteverted nares, and low-set ears. Proximal upper limb shortening, a small bell-shaped chest, talipes, and fixed flexion deformities of the wrists were seen. Neonatal atrial arrhythmia, highly suggestive of CS, was also present in two patients. One patient had congenital alveolar dysplasia, and another, born after 36 weeks' gestation, bronchopulmonary dysplasia. A rapidly fatal disease course, and the difficulty of identifying subtle dysmorphism in neonates requiring intensive care, suggest that this condition remains under-recognized, and should enter the differential diagnosis for very sick infants with a range of clinical problems including cardiac hypertrophy and disordered pulmonary development. Clinical management should be informed by knowledge of the poor prognosis of this condition.


Assuntos
Síndrome de Costello/genética , Genes ras/genética , Mutação INDEL , Síndrome de Costello/mortalidade , Diagnóstico Diferencial , Cardiopatias Congênitas , Humanos , Recém-Nascido
18.
Eur J Hum Genet ; 20(4): 381-8, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22126750

RESUMO

MLL2 mutations are detected in 55 to 80% of patients with Kabuki syndrome (KS). In 20 to 45% patients with KS, the genetic basis remains unknown, suggesting possible genetic heterogeneity. Here, we present the largest yet reported cohort of 116 patients with KS. We identified MLL2 variants in 74 patients, of which 47 are novel and a majority are truncating. We show that pathogenic missense mutations were commonly located in exon 48. We undertook a systematic facial KS morphology study of patients with KS at our regional dysmorphology meeting. Our data suggest that nearly all patients with typical KS facial features have pathogenic MLL2 mutations, although KS can be phenotypically variable. Furthermore, we show that MLL2 mutation-positive KS patients are more likely to have feeding problems, kidney anomalies, early breast bud development, joint dislocations and palatal malformations in comparison with MLL2 mutation-negative patients. Our work expands the mutation spectrum of MLL2 that may help in better understanding of this molecule, which is important in gene expression, epigenetic control of active chromatin states, embryonic development and cancer. Our analyses of the phenotype indicates that MLL2 mutation-positive and -negative patients differ systematically, and genetic heterogeneity of KS is not as extensive as previously suggested. Moreover, phenotypic variability of KS suggests that MLL2 testing should be considered even in atypical patients.


Assuntos
Anormalidades Múltiplas/genética , Proteínas de Ligação a DNA/genética , Heterogeneidade Genética , Doenças Hematológicas/genética , Mutação , Proteínas de Neoplasias/genética , Fenótipo , Doenças Vestibulares/genética , Estudos de Coortes , Face/anormalidades , Feminino , Humanos , Análise de Sequência de DNA
19.
Oncotarget ; 2(12): 1127-33, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22190405

RESUMO

The biological processes controlling human growth are diverse, complex and poorly understood. Genetic factors are important and human height has been shown to be a highly polygenic trait to which common and rare genetic variation contributes. Weaver syndrome is a human overgrowth condition characterised by tall stature, dysmorphic facial features, learning disability and variable additional features. We performed exome sequencing in four individuals with Weaver syndrome, identifying a mutation in the histone methyltransferase, EZH2, in each case. Sequencing of EZH2 in additional individuals with overgrowth identified a further 15 mutations. The EZH2 mutation spectrum in Weaver syndrome shows considerable overlap with the inactivating somatic EZH2 mutations recently reported in myeloid malignancies. Our data establish EZH2 mutations as the cause of Weaver syndrome and provide further links between histone modifications and regulation of human growth.


Assuntos
Anormalidades Múltiplas/genética , Hipotireoidismo Congênito/genética , Anormalidades Craniofaciais/genética , Proteínas de Ligação a DNA/genética , Mutação em Linhagem Germinativa , Deformidades Congênitas da Mão/genética , Fatores de Transcrição/genética , Sequência de Aminoácidos , Estatura , Proteína Potenciadora do Homólogo 2 de Zeste , Facies , Feminino , Transtornos do Crescimento/genética , Histona Metiltransferases , Histona-Lisina N-Metiltransferase/genética , Histonas/genética , Humanos , Masculino , Complexo Repressor Polycomb 2 , Análise de Sequência de DNA
20.
Clin Dysmorphol ; 20(4): 175-81, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21738022

RESUMO

Sotos syndrome is an overgrowth disorder with autosomal dominant inheritance caused by mutations and deletions in the nuclear receptor Set domain-containing protein 1 gene. In general, affected individuals have an advanced bone age, macrocephaly, characteristic facial gestalt and learning difficulties. Genotype-phenotype correlations are unclear. Full penetrance is seen and 95% of cases are de novo. Here, we report a three-generation pedigree, with at least eight affected individuals, shown to harbour the nuclear receptor Set domain-containing protein 1 missense mutation c. 6115C>T. To our knowledge, this is the largest Sotos family reported. The observed phenotype is extremely variable, thus highlighting the clinical heterogeneity that may occur.


Assuntos
Fenótipo , Síndrome de Sotos/diagnóstico , Síndrome de Sotos/genética , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Saúde da Família , Feminino , Estudos de Associação Genética , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Masculino , Pessoa de Meia-Idade , Mutação/genética , Irlanda do Norte , Proteínas Nucleares/genética , Linhagem , Adulto Jovem
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