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1.
Am J Med Genet A ; 179(9): 1884-1894, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31313512

RESUMO

Brachyolmia is a skeletal dysplasia characterized by short spine-short stature, platyspondyly, and minor long bone abnormalities. We describe 18 patients, from different ethnic backgrounds and ages ranging from infancy to 19 years, with the autosomal recessive form, associated with PAPSS2. The main clinical features include disproportionate short stature with short spine associated with variable symptoms of pain, stiffness, and spinal deformity. Eight patients presented prenatally with short femora, whereas later in childhood their short-spine phenotype emerged. We observed the same pattern of changing skeletal proportion in other patients. The radiological findings included platyspondyly, irregular end plates of the elongated vertebral bodies, narrow disc spaces and short over-faced pedicles. In the limbs, there was mild shortening of femoral necks and tibiae in some patients, whereas others had minor epiphyseal or metaphyseal changes. In all patients, exome and Sanger sequencing identified homozygous or compound heterozygous PAPSS2 variants, including c.809G>A, common to white European patients. Bi-parental inheritance was established where possible. Low serum DHEAS, but not overt androgen excess was identified. Our study indicates that autosomal recessive brachyolmia occurs across continents and may be under-recognized in infancy. This condition should be considered in the differential diagnosis of short femora presenting in the second trimester.

2.
Genet Med ; 2018 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-30245513

RESUMO

PURPOSE: Pathogenic variants in KAT6A have recently been identified as a cause of syndromic developmental delay. Within 2 years, the number of patients identified with pathogenic KAT6A variants has rapidly expanded and the full extent and variability of the clinical phenotype has not been reported. METHODS: We obtained data for patients with KAT6A pathogenic variants through three sources: treating clinicians, an online family survey distributed through social media, and a literature review. RESULTS: We identified 52 unreported cases, bringing the total number of published cases to 76. Our results expand the genotypic spectrum of pathogenic variants to include missense and splicing mutations. We functionally validated a pathogenic splice-site variant and identified a likely hotspot location for de novo missense variants. The majority of clinical features in KAT6A syndrome have highly variable penetrance. For core features such as intellectual disability, speech delay, microcephaly, cardiac anomalies, and gastrointestinal complications, genotype- phenotype correlations show that late-truncating pathogenic variants (exons 16-17) are significantly more prevalent. We highlight novel associations, including an increased risk of gastrointestinal obstruction. CONCLUSION: Our data expand the genotypic and phenotypic spectrum for individuals with genetic pathogenic variants in KAT6A and we outline appropriate clinical management.

3.
Am J Hum Genet ; 103(1): 3-18, 2018 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-29909963

RESUMO

Multiple primary tumors (MPTs) affect a substantial proportion of cancer survivors and can result from various causes, including inherited predisposition. Currently, germline genetic testing of MPT-affected individuals for variants in cancer-predisposition genes (CPGs) is mostly targeted by tumor type. We ascertained pre-assessed MPT individuals (with at least two primary tumors by age 60 years or at least three by 70 years) from genetics centers and performed whole-genome sequencing (WGS) on 460 individuals from 440 families. Despite previous negative genetic assessment and molecular investigations, pathogenic variants in moderate- and high-risk CPGs were detected in 67/440 (15.2%) probands. WGS detected variants that would not be (or were not) detected by targeted resequencing strategies, including low-frequency structural variants (6/440 [1.4%] probands). In most individuals with a germline variant assessed as pathogenic or likely pathogenic (P/LP), at least one of their tumor types was characteristic of variants in the relevant CPG. However, in 29 probands (42.2% of those with a P/LP variant), the tumor phenotype appeared discordant. The frequency of individuals with truncating or splice-site CPG variants and at least one discordant tumor type was significantly higher than in a control population (χ2 = 43.642; p ≤ 0.0001). 2/67 (3%) probands with P/LP variants had evidence of multiple inherited neoplasia allele syndrome (MINAS) with deleterious variants in two CPGs. Together with variant detection rates from a previous series of similarly ascertained MPT-affected individuals, the present results suggest that first-line comprehensive CPG analysis in an MPT cohort referred to clinical genetics services would detect a deleterious variant in about a third of individuals.

4.
Eur J Med Genet ; 2018 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-29698805

RESUMO

In the last 3 years de novo sequence variants in the ARID2 (AT-rich interaction domain 2) gene, a subunit of the SWI/SNF complex, have been linked to intellectual disabilities in 3 case reports including one which describes frameshift mutations in ARID2 in 2 patients with features resembling Coffin-Siris syndrome. Coffin-Siris syndrome (CSS) is a rare congenital syndrome characterized by intellectual deficit, coarse facial features and hypoplastic or absent fifth fingernails and/or toenails among other features. Mutations in a number of different genes encoding SWI/SNF chromatin remodelling complex proteins have been described but the underlying molecular cause remains unknown in approximately 40% of patients with CSS. Here we describe 7 unrelated individuals, 2 with deletions of the ARID2 region and 5 with de novo truncating mutations in the ARID2 gene. Similarities to CSS are evident. Although hypertrichosis and hypoplasia of the fifth finger nail and distal phalanx do not appear to be common in these patients, toenail hypoplasia and the presence of Wormian bones might support the involvement of ARID2.

5.
Am J Hum Genet ; 102(5): 985-994, 2018 05 03.
Artigo em Inglês | MEDLINE | ID: mdl-29656860

RESUMO

N-alpha-acetylation is a common co-translational protein modification that is essential for normal cell function in humans. We previously identified the genetic basis of an X-linked infantile lethal Mendelian disorder involving a c.109T>C (p.Ser37Pro) missense variant in NAA10, which encodes the catalytic subunit of the N-terminal acetyltransferase A (NatA) complex. The auxiliary subunit of the NatA complex, NAA15, is the dimeric binding partner for NAA10. Through a genotype-first approach with whole-exome or genome sequencing (WES/WGS) and targeted sequencing analysis, we identified and phenotypically characterized 38 individuals from 33 unrelated families with 25 different de novo or inherited, dominantly acting likely gene disrupting (LGD) variants in NAA15. Clinical features of affected individuals with LGD variants in NAA15 include variable levels of intellectual disability, delayed speech and motor milestones, and autism spectrum disorder. Additionally, mild craniofacial dysmorphology, congenital cardiac anomalies, and seizures are present in some subjects. RNA analysis in cell lines from two individuals showed degradation of the transcripts with LGD variants, probably as a result of nonsense-mediated decay. Functional assays in yeast confirmed a deleterious effect for two of the LGD variants in NAA15. Further supporting a mechanism of haploinsufficiency, individuals with copy-number variant (CNV) deletions involving NAA15 and surrounding genes can present with mild intellectual disability, mild dysmorphic features, motor delays, and decreased growth. We propose that defects in NatA-mediated N-terminal acetylation (NTA) lead to variable levels of neurodevelopmental disorders in humans, supporting the importance of the NatA complex in normal human development.

6.
Am J Hum Genet ; 101(6): 1021-1033, 2017 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-29220674

RESUMO

ACTB encodes ß-actin, an abundant cytoskeletal housekeeping protein. In humans, postulated gain-of-function missense mutations cause Baraitser-Winter syndrome (BRWS), characterized by intellectual disability, cortical malformations, coloboma, sensorineural deafness, and typical facial features. To date, the consequences of loss-of-function ACTB mutations have not been proven conclusively. We describe heterozygous ACTB deletions and nonsense and frameshift mutations in 33 individuals with developmental delay, apparent intellectual disability, increased frequency of internal organ malformations (including those of the heart and the renal tract), growth retardation, and a recognizable facial gestalt (interrupted wavy eyebrows, dense eyelashes, wide nose, wide mouth, and a prominent chin) that is distinct from characteristics of individuals with BRWS. Strikingly, this spectrum overlaps with that of several chromatin-remodeling developmental disorders. In wild-type mouse embryos, ß-actin expression was prominent in the kidney, heart, and brain. ACTB mRNA expression levels in lymphoblastic lines and fibroblasts derived from affected individuals were decreased in comparison to those in control cells. Fibroblasts derived from an affected individual and ACTB siRNA knockdown in wild-type fibroblasts showed altered cell shape and migration, consistent with known roles of cytoplasmic ß-actin. We also demonstrate that ACTB haploinsufficiency leads to reduced cell proliferation, altered expression of cell-cycle genes, and decreased amounts of nuclear, but not cytoplasmic, ß-actin. In conclusion, we show that heterozygous loss-of-function ACTB mutations cause a distinct pleiotropic malformation syndrome with intellectual disability. Our biological studies suggest that a critically reduced amount of this protein alters cell shape, migration, proliferation, and gene expression to the detriment of brain, heart, and kidney development.


Assuntos
Anormalidades Múltiplas/genética , Actinas/genética , Deficiências do Desenvolvimento/genética , Haploinsuficiência/genética , Actinas/biossíntese , Adolescente , Adulto , Idoso , Animais , Ciclo Celular/genética , Proliferação de Células/genética , Criança , Pré-Escolar , Códon sem Sentido/genética , Coloboma/genética , Facies , Feminino , Mutação da Fase de Leitura/genética , Deleção de Genes , Humanos , Lactente , Recém-Nascido , Deficiência Intelectual/genética , Masculino , Malformações do Desenvolvimento Cortical/genética , Camundongos , Interferência de RNA , RNA Interferente Pequeno/genética , Adulto Jovem
7.
Am J Hum Genet ; 101(4): 503-515, 2017 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-28942966

RESUMO

Bromodomain PHD finger transcription factor (BPTF) is the largest subunit of nucleosome remodeling factor (NURF), a member of the ISWI chromatin-remodeling complex. However, the clinical consequences of disruption of this complex remain largely uncharacterized. BPTF is required for anterior-posterior axis formation of the mouse embryo and was shown to promote posterior neuroectodermal fate by enhancing Smad2-activated wnt8 expression in zebrafish. Here, we report eight loss-of-function and two missense variants (eight de novo and two of unknown origin) in BPTF on 17q24.2. The BPTF variants were found in unrelated individuals aged between 2.1 and 13 years, who manifest variable degrees of developmental delay/intellectual disability (10/10), speech delay (10/10), postnatal microcephaly (7/9), and dysmorphic features (9/10). Using CRISPR-Cas9 genome editing of bptf in zebrafish to induce a loss of gene function, we observed a significant reduction in head size of F0 mutants compared to control larvae. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and phospho-histone H3 (PH3) staining to assess apoptosis and cell proliferation, respectively, showed a significant increase in cell death in F0 mutants compared to controls. Additionally, we observed a substantial increase of the ceratohyal angle of the craniofacial skeleton in bptf F0 mutants, indicating abnormal craniofacial patterning. Taken together, our data demonstrate the pathogenic role of BPTF haploinsufficiency in syndromic neurodevelopmental anomalies and extend the clinical spectrum of human disorders caused by ablation of chromatin remodeling complexes.


Assuntos
Anormalidades Múltiplas/genética , Antígenos Nucleares/genética , Anormalidades Craniofaciais/genética , Regulação da Expressão Gênica no Desenvolvimento , Haploinsuficiência/genética , Transtornos do Desenvolvimento da Linguagem/genética , Microcefalia/genética , Proteínas do Tecido Nervoso/genética , Fatores de Transcrição/genética , Anormalidades Múltiplas/patologia , Adolescente , Animais , Antígenos Nucleares/metabolismo , Sistemas CRISPR-Cas , Proliferação de Células , Células Cultivadas , Criança , Pré-Escolar , Montagem e Desmontagem da Cromatina , Estudos de Coortes , Anormalidades Craniofaciais/patologia , Feminino , Edição de Genes , Haploinsuficiência/fisiologia , Humanos , Transtornos do Desenvolvimento da Linguagem/patologia , Larva/genética , Larva/crescimento & desenvolvimento , Masculino , Microcefalia/patologia , Proteínas do Tecido Nervoso/antagonistas & inibidores , Proteínas do Tecido Nervoso/metabolismo , Neurônios/metabolismo , Neurônios/patologia , Fenótipo , Fatores de Transcrição/antagonistas & inibidores , Fatores de Transcrição/metabolismo , Peixe-Zebra/genética , Peixe-Zebra/crescimento & desenvolvimento
8.
Am J Hum Genet ; 100(1): 75-90, 2017 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-28041643

RESUMO

Inherited retinal disease is a common cause of visual impairment and represents a highly heterogeneous group of conditions. Here, we present findings from a cohort of 722 individuals with inherited retinal disease, who have had whole-genome sequencing (n = 605), whole-exome sequencing (n = 72), or both (n = 45) performed, as part of the NIHR-BioResource Rare Diseases research study. We identified pathogenic variants (single-nucleotide variants, indels, or structural variants) for 404/722 (56%) individuals. Whole-genome sequencing gives unprecedented power to detect three categories of pathogenic variants in particular: structural variants, variants in GC-rich regions, which have significantly improved coverage compared to whole-exome sequencing, and variants in non-coding regulatory regions. In addition to previously reported pathogenic regulatory variants, we have identified a previously unreported pathogenic intronic variant in CHM in two males with choroideremia. We have also identified 19 genes not previously known to be associated with inherited retinal disease, which harbor biallelic predicted protein-truncating variants in unsolved cases. Whole-genome sequencing is an increasingly important comprehensive method with which to investigate the genetic causes of inherited retinal disease.


Assuntos
Análise Mutacional de DNA , Variação Genética/genética , Genoma Humano/genética , Doenças Retinianas/genética , Proteínas Adaptadoras de Transdução de Sinal/genética , Alelos , Sequência de Bases , Coroideremia/genética , Grupos Étnicos/genética , Exoma/genética , Feminino , Genes Recessivos/genética , Humanos , Íntrons/genética , Masculino , Mutação , Doenças Raras/genética
9.
Neurogenetics ; 18(1): 49-55, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-28063088

RESUMO

Charcot-Marie-Tooth disease (CMT) refers to a genetically heterogeneous group of disorders which cause a peripheral motor and sensory neuropathy. The overall prevalence is 1 in 2500 individuals. Mutations in the MFN2 gene are the commonest cause for the axonal (CMT2) type. We describe a Caucasian 5-year old girl affected by CMT2A since the age of 2 years. She presented with unsteady gait, in-turning of the feet and progressive foot deformities. Nerve conduction studies suggested an axonal neuropathy and molecular testing identified a previously reported pathogenic variant c.1090C > T, p.(Arg364Trp) in the MFN2 gene. This variant was also detected in a mosaic state in blood and saliva by Sanger sequencing in her subjectively healthy father. Next generation sequencing showed that the level of mosaicism was 21% in blood and 24% in saliva. A high recurrence risk was given because the father had proven somatic mosaicism and an affected child implying gonadal mosaicism. The parents were referred for pre-implantation genetic diagnosis. To the best of our knowledge, this is the first reported case of somatic mosaicism for MFN2. This study has important implications for genetic counselling in families with CMT2A.


Assuntos
Doença de Charcot-Marie-Tooth/genética , Doença de Charcot-Marie-Tooth/patologia , GTP Fosfo-Hidrolases/genética , Proteínas Mitocondriais/genética , Mosaicismo , Mutação de Sentido Incorreto , Adulto , Pré-Escolar , Relações Pai-Filho , Feminino , Humanos , Masculino , Núcleo Familiar , Pais , Linhagem , Fenótipo , Índice de Gravidade de Doença
10.
Am J Med Genet A ; 167A(3): 504-11, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25572454

RESUMO

Interstitial microdeletions of 20q chromosome are rare, only 17 patients have been reported in the literature to date. Among them, only six carried a proximal 20q11.21-q11.23 deletion, with a size ranging from 2.6 to 6.8 Mb. The existence of a 20q11.2 microdeletion syndrome has been proposed, based on five previously reported cases that displayed anomalies of the extremities, intellectual disability, feeding difficulties, craniofacial dysmorphism and variable malformations. To further characterize this syndrome, we report on six new patients with 20q11.2 microdeletions diagnosed by whole-genome array-based comparative genomic hybridization. These patient reports more precisely refined the phenotype and narrowed the minimal critical region involved in this syndrome. Careful clinical assessment confirms the distinctive clinical phenotype. The craniofacial dysmorphism consists of high forehead, frontal bossing, enophthalmos, and midface hypoplasia. We have identified a 1.62 megabase minimal critical region involved in this syndrome encompassing three genes­GDF5, EPB41L1, andSAMHD1­which are strong candidates for different aspects of the phenotype. These results support that 20q11.2 microdeletion syndrome is a new contiguous gene deletion syndrome with a recognizable phenotype.


Assuntos
Anormalidades Múltiplas/diagnóstico , Anormalidades Múltiplas/genética , Deleção Cromossômica , Cromossomos Humanos Par 20 , Fenótipo , Adolescente , Criança , Pré-Escolar , Aberrações Cromossômicas , Pontos de Quebra do Cromossomo , Hibridização Genômica Comparativa , Facies , Feminino , Estudos de Associação Genética , Humanos , Lactente , Cariotipagem , Masculino , Síndrome , Adulto Jovem
11.
Eur J Hum Genet ; 23(9): 1165-70, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25424711

RESUMO

KAT6B sequence variants have been identified previously in both patients with the Say-Barber-Biesecker type of blepharophimosis mental retardation syndromes (SBBS) and in the more severe genitopatellar syndrome (GPS). We report on the findings in a previously unreported group of 57 individuals with suggestive features of SBBS or GPS. Likely causative variants have been identified in 34/57 patients and were commonly located in the terminal exons of KAT6B. Of those where parental samples could be tested, all occurred de novo. Thirty out of thirty-four had truncating variants, one had a missense variant and the remaining three had the same synonymous change predicted to affect splicing. Variants in GPS tended to occur more proximally to those in SBBS patients, and genotype/phenotype analysis demonstrated significant clinical overlap between SBBS and GPS. The de novo synonymous change seen in three patients with features of SBBS occurred more proximally in exon 16. Statistical analysis of clinical features demonstrated that KAT6B variant-positive patients were more likely to display hypotonia, feeding difficulties, long thumbs/great toes and dental, thyroid and patella abnormalities than KAT6B variant-negative patients. The few reported patients with KAT6B haploinsufficiency had a much milder phenotype, though with some features overlapping those of SBBS. We report the findings in a previously unreported patient with a deletion of the KAT6B gene to further delineate the haploinsufficiency phenotype. The molecular mechanisms giving rise to the SBBS and GPS phenotypes are discussed.


Assuntos
Blefarofimose/genética , Hipotireoidismo Congênito/genética , Anormalidades Craniofaciais/genética , Éxons , Cardiopatias Congênitas/genética , Histona Acetiltransferases/genética , Deficiência Intelectual/genética , Instabilidade Articular/genética , Rim/anormalidades , Mutação , Patela/anormalidades , Transtornos Psicomotores/genética , Escroto/anormalidades , Anormalidades Urogenitais/genética , Blefarofimose/diagnóstico , Blefarofimose/patologia , Pré-Escolar , Hipotireoidismo Congênito/diagnóstico , Hipotireoidismo Congênito/patologia , Anormalidades Craniofaciais/diagnóstico , Anormalidades Craniofaciais/patologia , Análise Mutacional de DNA , Diagnóstico Diferencial , Exoma , Facies , Feminino , Expressão Gênica , Estudos de Associação Genética , Genótipo , Cardiopatias Congênitas/diagnóstico , Cardiopatias Congênitas/patologia , Humanos , Deficiência Intelectual/diagnóstico , Deficiência Intelectual/patologia , Instabilidade Articular/diagnóstico , Instabilidade Articular/patologia , Rim/patologia , Masculino , Patela/patologia , Fenótipo , Transtornos Psicomotores/diagnóstico , Transtornos Psicomotores/patologia , Escroto/patologia , Índice de Gravidade de Doença , Anormalidades Urogenitais/diagnóstico , Anormalidades Urogenitais/patologia
13.
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
14.
Med J Aust ; 199(7): 437, 2013 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-24099182
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