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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.
Am J Hum Genet ; 104(4): 709-720, 2019 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-30905399

RESUMO

The Mediator is an evolutionarily conserved, multi-subunit complex that regulates multiple steps of transcription. Mediator activity is regulated by the reversible association of a four-subunit module comprising CDK8 or CDK19 kinases, together with cyclin C, MED12 or MED12L, and MED13 or MED13L. Mutations in MED12, MED13, and MED13L were previously identified in syndromic developmental disorders with overlapping phenotypes. Here, we report CDK8 mutations (located at 13q12.13) that cause a phenotypically related disorder. Using whole-exome or whole-genome sequencing, and by international collaboration, we identified eight different heterozygous missense CDK8 substitutions, including 10 shown to have arisen de novo, in 12 unrelated subjects; a recurrent mutation, c.185C>T (p.Ser62Leu), was present in five individuals. All predicted substitutions localize to the ATP-binding pocket of the kinase domain. Affected individuals have overlapping phenotypes characterized by hypotonia, mild to moderate intellectual disability, behavioral disorders, and variable facial dysmorphism. Congenital heart disease occurred in six subjects; additional features present in multiple individuals included agenesis of the corpus callosum, ano-rectal malformations, seizures, and hearing or visual impairments. To evaluate the functional impact of the mutations, we measured phosphorylation at STAT1-Ser727, a known CDK8 substrate, in a CDK8 and CDK19 CRISPR double-knockout cell line transfected with wild-type (WT) or mutant CDK8 constructs. These experiments demonstrated a reduction in STAT1 phosphorylation by all mutants, in most cases to a similar extent as in a kinase-dead control. We conclude that missense mutations in CDK8 cause a developmental disorder that has phenotypic similarity to syndromes associated with mutations in other subunits of the Mediator kinase module, indicating probable overlap in pathogenic mechanisms.

3.
Hum Mutat ; 39(1): 103-113, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29024177

RESUMO

Loss-of-function mutations in the X-linked gene FLNA can lead to abnormal neuronal migration, vascular and cardiac defects, and congenital intestinal pseudo-obstruction (CIPO), the latter characterized by anomalous intestinal smooth muscle layering. Survival in male hemizygotes for such mutations is dependent on retention of residual FLNA function but it is unclear why a subgroup of males with mutations in the 5' end of the gene can present with CIPO alone. Here, we demonstrate evidence for the presence of two FLNA isoforms differing by 28 residues at the N-terminus initiated at ATG+1 and ATG+82 . A male with CIPO (c.18_19del) exclusively expressed FLNA ATG+82 , implicating the longer protein isoform (ATG+1 ) in smooth muscle development. In contrast, mutations leading to reduction of both isoforms are associated with compound phenotypes affecting the brain, heart, and intestine. RNA-seq data revealed three distinct transcription start sites, two of which produce a protein isoform utilizing ATG+1 while the third utilizes ATG+82 . Transcripts sponsoring translational initiation at ATG+1 predominate in intestinal smooth muscle, and are more abundant compared with the level measured in fibroblasts. Together these observations describe a new mechanism of tissue-specific regulation of FLNA that could reflect the differing mechanical requirements of these cell types during development.


Assuntos
Filaminas/genética , Estudos de Associação Genética , Heterogeneidade Genética , Mutação com Perda de Função , Fenótipo , Transcrição Genética , Adolescente , Encéfalo/anormalidades , Encéfalo/diagnóstico por imagem , Criança , Sequência Conservada , Análise Mutacional de DNA , Feminino , Filaminas/química , Filaminas/metabolismo , Trato Gastrointestinal/metabolismo , Expressão Gênica , Humanos , Imagem por Ressonância Magnética , Masculino , Músculo Liso/metabolismo , Isoformas de Proteínas , Adulto Jovem
4.
J Med Genet ; 55(1): 28-38, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29021403

RESUMO

INTRODUCTION: Recent evidence has emerged linking mutations in CDK13 to syndromic congenital heart disease. We present here genetic and phenotypic data pertaining to 16 individuals with CDK13 mutations. METHODS: Patients were investigated by exome sequencing, having presented with developmental delay and additional features suggestive of a syndromic cause. RESULTS: Our cohort comprised 16 individuals aged 4-16 years. All had developmental delay, including six with autism spectrum disorder. Common findings included feeding difficulties (15/16), structural cardiac anomalies (9/16), seizures (4/16) and abnormalities of the corpus callosum (4/11 patients who had undergone MRI). All had craniofacial dysmorphism, with common features including short, upslanting palpebral fissures, hypertelorism or telecanthus, medial epicanthic folds, low-set, posteriorly rotated ears and a small mouth with thin upper lip vermilion. Fifteen patients had predicted missense mutations, including five identical p.(Asn842Ser) substitutions and two p.(Gly717Arg) substitutions. One patient had a canonical splice acceptor site variant (c.2898-1G>A). All mutations were located within the protein kinase domain of CDK13. The affected amino acids are highly conserved, and in silico analyses including comparative protein modelling predict that they will interfere with protein function. The location of the missense mutations in a key catalytic domain suggests that they are likely to cause loss of catalytic activity but retention of cyclin K binding, resulting in a dominant negative mode of action. Although the splice-site mutation was predicted to produce a stable internally deleted protein, this was not supported by expression studies in lymphoblastoid cells. A loss of function contribution to the underlying pathological mechanism therefore cannot be excluded, and the clinical significance of this variant remains uncertain. CONCLUSIONS: These patients demonstrate that heterozygous, likely dominant negative mutations affecting the protein kinase domain of the CDK13 gene result in a recognisable, syndromic form of intellectual disability, with or without congenital heart disease.


Assuntos
Proteína Quinase CDC2/química , Proteína Quinase CDC2/genética , Deficiências do Desenvolvimento/genética , Deficiência Intelectual/genética , Mutação/genética , Adolescente , Criança , Sequência Conservada , Feminino , Heterozigoto , Humanos , Masculino , Modelos Moleculares , Mutação de Sentido Incorreto/genética , Domínios Proteicos , Síndrome , Termodinâmica
6.
Neurogenetics ; 18(2): 111-117, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28229249

RESUMO

We describe a family with an autosomal dominant familial dyskinesia resembling myoclonus-dystonia associated with a novel missense mutation in ADCY5, found through whole-exome sequencing. A tiered analytical approach was used to analyse whole-exome sequencing data from an affected grandmother-granddaughter pair. Whole-exome sequencing identified 18,000 shared variants, of which 46 were non-synonymous changes not present in a local cohort of control exomes (n = 422). Further filtering based on predicted splicing effect, minor allele frequency in the 1000 Genomes Project and on phylogenetic conservation yielded 13 candidate variants, of which the heterozygous missense mutation c.3086T>G, p. M1029R in ADCY5 most closely matched the observed phenotype. This report illustrates the utility of whole-exome sequencing in cases of undiagnosed movement disorders with clear autosomal dominant inheritance. Moreover, ADCY5 mutations should be considered in cases with apparent myoclonus-dystonia, particularly where SCGE mutations have been excluded. ADCY5-related dyskinesia may manifest variable expressivity within a single family, and affected individuals may be initially diagnosed with differing neurological phenotypes.


Assuntos
Adenilil Ciclases/genética , Discinesias/genética , Distúrbios Distônicos/genética , Adolescente , Adulto , Pré-Escolar , Discinesias/complicações , Distúrbios Distônicos/complicações , Família , Feminino , Humanos , Pessoa de Meia-Idade , Mutação de Sentido Incorreto , Linhagem , Fenótipo
7.
Nat Genet ; 49(3): 457-464, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28092684

RESUMO

Deadenylases are best known for degrading the poly(A) tail during mRNA decay. The deadenylase family has expanded throughout evolution and, in mammals, consists of 12 Mg2+-dependent 3'-end RNases with substrate specificity that is mostly unknown. Pontocerebellar hypoplasia type 7 (PCH7) is a unique recessive syndrome characterized by neurodegeneration and ambiguous genitalia. We studied 12 human families with PCH7, uncovering biallelic, loss-of-function mutations in TOE1, which encodes an unconventional deadenylase. toe1-morphant zebrafish displayed midbrain and hindbrain degeneration, modeling PCH-like structural defects in vivo. Surprisingly, we found that TOE1 associated with small nuclear RNAs (snRNAs) incompletely processed spliceosomal. These pre-snRNAs contained 3' genome-encoded tails often followed by post-transcriptionally added adenosines. Human cells with reduced levels of TOE1 accumulated 3'-end-extended pre-snRNAs, and the immunoisolated TOE1 complex was sufficient for 3'-end maturation of snRNAs. Our findings identify the cause of a neurodegenerative syndrome linked to snRNA maturation and uncover a key factor involved in the processing of snRNA 3' ends.


Assuntos
Doenças Cerebelares/genética , Exonucleases/genética , Mutação/genética , Proteínas Nucleares/genética , RNA Nuclear Pequeno/genética , Alelos , Animais , Feminino , Humanos , Masculino , Camundongos , Doenças Neurodegenerativas/genética , RNA Mensageiro/genética , Spliceossomos/genética , Peixe-Zebra
8.
Nat Genet ; 49(2): 223-237, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27992417

RESUMO

Histone lysine methylation, mediated by mixed-lineage leukemia (MLL) proteins, is now known to be critical in the regulation of gene expression, genomic stability, cell cycle and nuclear architecture. Despite MLL proteins being postulated as essential for normal development, little is known about the specific functions of the different MLL lysine methyltransferases. Here we report heterozygous variants in the gene KMT2B (also known as MLL4) in 27 unrelated individuals with a complex progressive childhood-onset dystonia, often associated with a typical facial appearance and characteristic brain magnetic resonance imaging findings. Over time, the majority of affected individuals developed prominent cervical, cranial and laryngeal dystonia. Marked clinical benefit, including the restoration of independent ambulation in some cases, was observed following deep brain stimulation (DBS). These findings highlight a clinically recognizable and potentially treatable form of genetic dystonia, demonstrating the crucial role of KMT2B in the physiological control of voluntary movement.


Assuntos
Distonia/genética , Histona-Lisina N-Metiltransferase/genética , Mutação/genética , Adolescente , Proteínas de Ligação a DNA/genética , Feminino , Histona Metiltransferases , Histonas/genética , Humanos , Lisina/genética , Masculino , Metilação , Proteínas Nucleares/genética
9.
JAMA Neurol ; 73(12): 1433-1439, 2016 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-27749956

RESUMO

Importance: Adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP) is a frequent cause of adult-onset leukodystrophy known to be caused by autosomal dominant mutations in the CSF1R (colony-stimulating factor 1) gene. The discovery that CSF1R mutations cause ALSP led to more accurate prognosis and genetic counseling for these patients in addition to increased interest in microglia as a target in neurodegeneration. However, it has been known since the discovery of the CSF1R gene that there are patients with typical clinical and radiologic evidence of ALSP who do not carry pathogenic CSF1R mutations. These patients include those in whom the pathognomonic features of axonal spheroids and pigmented microglia have been found. Achieving a genetic diagnosis in these patients is important to our understanding of this disorder. Objective: To genetically characterize a group of patients with typical features of ALSP who do not carry CSF1R mutations. Design, Settings, and Participants: In this case series study, 5 patients from 4 families were identified with clinical, radiologic, or pathologic features of ALSP in whom CSF1R mutations had been excluded previously by sequencing. Data were collected between May 2014 and September 2015 and analyzed between September 2015 and February 2016. Main Outcomes and Measures: Focused exome sequencing was used to identify candidate variants. Family studies, long-range polymerase chain reaction with cloning, and complementary DNA sequencing were used to confirm pathogenicity. Results: Of these 5 patients, 4 were men (80%); mean age at onset of ALSP was 29 years (range, 15-44 years). Biallelic mutations in the alanyl-transfer (t)RNA synthetase 2 (AARS2) gene were found in all 5 patients. Frameshifting and splice site mutations were common, found in 4 of 5 patients, and sequencing of complementary DNA from affected patients confirmed that the variants were loss of function. All patients presented in adulthood with prominent cognitive, neuropsychiatric, and upper motor neuron signs. Magnetic resonance imaging in all patients demonstrated a symmetric leukoencephalopathy with punctate regions of restricted diffusion, typical of ALSP. In 1 patient, brain biopsy demonstrated axonal spheroids and pigmented microglia, which are the pathognomonic signs of ALSP. Conclusions and Relevance: This work indicates that mutations in the tRNA synthetase AARS2 gene cause a recessive form of ALSP. The CSF1R and AARS2 proteins have different cellular functions but overlap in a final common pathway of neurodegeneration. This work points to novel targets for research and will lead to improved diagnostic rates in patients with adult-onset leukoencephalopathy.


Assuntos
Alanina-tRNA Ligase/genética , Leucoencefalopatias/diagnóstico por imagem , Leucoencefalopatias/genética , Leucoencefalopatias/fisiopatologia , Microglia/patologia , Adolescente , Adulto , Exoma , Feminino , Humanos , Imagem por Ressonância Magnética , Masculino , Mutação , Linhagem , Análise de Sequência de DNA , Adulto Jovem
10.
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
11.
Nat Genet ; 48(8): 877-87, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-27399968

RESUMO

Numerous genes are associated with neurodevelopmental disorders such as intellectual disability and autism spectrum disorder (ASD), but their dysfunction is often poorly characterized. Here we identified dominant mutations in the gene encoding the transcriptional repressor and MeCP2 interactor switch-insensitive 3 family member A (SIN3A; chromosome 15q24.2) in individuals who, in addition to mild intellectual disability and ASD, share striking features, including facial dysmorphisms, microcephaly and short stature. This phenotype is highly related to that of individuals with atypical 15q24 microdeletions, linking SIN3A to this microdeletion syndrome. Brain magnetic resonance imaging showed subtle abnormalities, including corpus callosum hypoplasia and ventriculomegaly. Intriguingly, in vivo functional knockdown of Sin3a led to reduced cortical neurogenesis, altered neuronal identity and aberrant corticocortical projections in the developing mouse brain. Together, our data establish that haploinsufficiency of SIN3A is associated with mild syndromic intellectual disability and that SIN3A can be considered to be a key transcriptional regulator of cortical brain development.


Assuntos
Córtex Cerebral/patologia , Haploinsuficiência/genética , Deficiência Intelectual/patologia , Proteína 2 de Ligação a Metil-CpG/metabolismo , Mutação/genética , Neurogênese/fisiologia , Proteínas Repressoras/genética , Anormalidades Múltiplas , Adolescente , Adulto , Agenesia do Corpo Caloso/genética , Agenesia do Corpo Caloso/patologia , Animais , Córtex Cerebral/metabolismo , Criança , Pré-Escolar , Deleção Cromossômica , Feminino , Humanos , Deficiência Intelectual/genética , Masculino , Camundongos , Pessoa de Meia-Idade , Fenótipo , Proteínas Repressoras/metabolismo , Síndrome , Adulto Jovem
12.
Am J Med Genet A ; 170(6): 1556-63, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-26940150

RESUMO

Proteoglycans are components of the extracellular matrix with diverse biological functions. Defects in proteoglycan synthesis have been linked to several human diseases with common features of short stature, hypermobility, joint dislocations, and skeletal dysplasia. B4GALT7 encodes galactosyltransferase-I that catalyzes the addition of a galactose moiety to a xylosyl group in the tetrasaccharide linker of proteoglycans. Mutations in this gene have been associated with the rare progeroid form of Ehlers Danlos syndrome and in addition more recently found to underlie Larsen of Reunion Island syndrome. Nine individuals have been reported with a diagnosis of the progeroid form of Ehlers Danlos syndrome, four of whom have had molecular characterization showing homozygous or compound heterozygous mutations in B4GALT7. We report two newly described patients with compound heterozygous mutations in B4GALT7, and show that the six individuals with confirmed mutations do not have the progeroid features described in the original five patients with a clinical diagnosis of the progeroid form of Ehlers Danlos syndrome. We suggest that galactosyltransferase-I deficiency does not cause the progeroid form of Ehlers Danlos syndrome, but instead results in a clinically recognizable syndrome comprising short stature, joint hypermobility, radioulnar synostosis, and severe hypermetropia. This group of syndromic patients are on a phenotypic spectrum with individuals who have Larsen of Reunion Island syndrome, although the key features of osteopenia, fractures and hypermetropia have not been reported in patients from Reunion Island. © 2016 Wiley Periodicals, Inc.


Assuntos
Galactosiltransferases/genética , Estudos de Associação Genética , Mutação , Fenótipo , Substituição de Aminoácidos , Densidade Óssea , Códon , Ecocardiografia , Síndrome de Ehlers-Danlos/diagnóstico , Síndrome de Ehlers-Danlos/genética , Facies , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Radiografia , Síndrome
13.
Am J Med Genet A ; 170(3): 670-5, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26842493

RESUMO

We report on 19 individuals with a recurrent de novo c.607C>T mutation in PACS1. This specific mutation gives rise to a recognizable intellectual disability syndrome. There is a distinctive facial appearance (19/19), characterized by full and arched eyebrows, hypertelorism with downslanting palpebral fissures, long eye lashes, ptosis, low set and simple ears, bulbous nasal tip, wide mouth with downturned corners and a thin upper lip with an unusual "wavy" profile, flat philtrum, and diastema of the teeth. Intellectual disability, ranging from mild to moderate, was present in all. Hypotonia is common in infancy (8/19). Seizures are frequent (12/19) and respond well to anticonvulsive medication. Structural malformations are common, including heart (10/19), brain (12/16), eye (10/19), kidney (3/19), and cryptorchidism (6/12 males). Feeding dysfunction is presenting in infancy with failure to thrive (5/19), gastroesophageal reflux (6/19), and gastrostomy tube placement (4/19). There is persistence of oral motor dysfunction. We provide suggestions for clinical work-up and management and hope that the present study will facilitate clinical recognition of further cases.


Assuntos
Anormalidades Múltiplas/genética , Deficiência Intelectual/genética , Mutação Puntual , Convulsões/genética , Proteínas de Transporte Vesicular/genética , Anormalidades Múltiplas/diagnóstico , Anormalidades Múltiplas/tratamento farmacológico , Anormalidades Múltiplas/patologia , Adolescente , Anticonvulsivantes/uso terapêutico , Criança , Pré-Escolar , Facies , Insuficiência de Crescimento/diagnóstico , Insuficiência de Crescimento/tratamento farmacológico , Insuficiência de Crescimento/genética , Insuficiência de Crescimento/patologia , Feminino , Expressão Gênica , Humanos , Deficiência Intelectual/diagnóstico , Deficiência Intelectual/tratamento farmacológico , Deficiência Intelectual/patologia , Masculino , Hipotonia Muscular/diagnóstico , Hipotonia Muscular/tratamento farmacológico , Hipotonia Muscular/genética , Hipotonia Muscular/patologia , Convulsões/diagnóstico , Convulsões/tratamento farmacológico , Convulsões/patologia , Índice de Gravidade de Doença , Síndrome , Adulto Jovem
14.
Nat Genet ; 47(11): 1363-9, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26437029

RESUMO

Discovery of most autosomal recessive disease-associated genes has involved analysis of large, often consanguineous multiplex families or small cohorts of unrelated individuals with a well-defined clinical condition. Discovery of new dominant causes of rare, genetically heterogeneous developmental disorders has been revolutionized by exome analysis of large cohorts of phenotypically diverse parent-offspring trios. Here we analyzed 4,125 families with diverse, rare and genetically heterogeneous developmental disorders and identified four new autosomal recessive disorders. These four disorders were identified by integrating Mendelian filtering (selecting probands with rare, biallelic and putatively damaging variants in the same gene) with statistical assessments of (i) the likelihood of sampling the observed genotypes from the general population and (ii) the phenotypic similarity of patients with recessive variants in the same candidate gene. This new paradigm promises to catalyze the discovery of novel recessive disorders, especially those with less consistent or nonspecific clinical presentations and those caused predominantly by compound heterozygous genotypes.


Assuntos
Deficiências do Desenvolvimento/genética , Genes Recessivos , Estudos de Associação Genética/métodos , Predisposição Genética para Doença/genética , Proteínas de Ciclo Celular/genética , Deficiências do Desenvolvimento/classificação , Exoma/genética , Saúde da Família , Feminino , Variação Genética , Genótipo , Humanos , Masculino , Metaloproteinases da Matriz Secretadas/genética , Linhagem , Fenótipo , Proteína-Arginina N-Metiltransferases/genética , Análise de Sequência de DNA/métodos , Ubiquitina-Proteína Ligases/genética , Reino Unido
15.
Am J Med Genet A ; 167A(12): 3153-60, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26333682

RESUMO

Submicroscopic deletions within chromosome 1q24q25 are associated with a syndromic phenotype of short stature, brachydactyly, learning difficulties, and facial dysmorphism. The critical region for the deletion phenotype has previously been narrowed to a 1.9 Mb segment containing 13 genes. We describe two further patients with 1q24 microdeletions and the skeletal phenotype, the first of whom has normal intellect, whereas the second has only mild learning impairment. The deletion in the first patient is very small and further narrows the critical interval for the striking skeletal aspects of this condition to a region containing only Dynamin 3 (DNM3) and two microRNAs that are harbored within intron 14 of this gene: miR199 and miR214. Mouse studies raise the possibility that these microRNAs may be implicated in the short stature and skeletal abnormalities of this microdeletion condition. The deletion in the second patient spans the previously reported critical region and indicates that the cognitive impairment may not always be as severe as previous reports suggest.


Assuntos
Anormalidades Múltiplas/genética , Doenças do Desenvolvimento Ósseo/genética , Deleção Cromossômica , Cromossomos Humanos Par 1/genética , Dinamina III/genética , MicroRNAs/genética , Anormalidades Múltiplas/patologia , Adolescente , Adulto , Animais , Doenças do Desenvolvimento Ósseo/patologia , Braquidactilia/genética , Braquidactilia/patologia , Hibridização Genômica Comparativa , Feminino , Humanos , Recém-Nascido , Deficiência Intelectual/genética , Deficiência Intelectual/patologia , Masculino , Camundongos , Fenótipo , Prognóstico , Síndrome , Gêmeos Monozigóticos/genética
16.
Sci Rep ; 5: 10042, 2015 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-25975230

RESUMO

We report a new family with autosomal dominant inheritance of a late onset rapidly progressive leukodystrophy in which exome sequencing has revealed a novel mutation p.R782G in the Colony-Stimulating Factor 1 Receptor gene (CSF1R). Neuropathology of two affected family members showed cerebral white matter degeneration with axonal swellings and pigmented macrophages. The few recently reported families with CSF1R mutations had been previously labelled "hereditary diffuse leukencephalopathy with axonal spheroids" (HDLS) and "pigmentary orthochromatic leukodystrophy" (POLD), disorders which now appear to form a disease continuum. The term "adult-onset leukoencephalopathy with axonal spheroids and pigmented glia" (ALSP) has been proposed to encompass this spectrum. As CSF1R regulates microglia this mutation implies that dysregulation of microglia is the primary cause of the disease.


Assuntos
Axônios/patologia , Neuroglia/patologia , Receptor de Fator Estimulador de Colônias de Macrófagos/genética , Substância Branca/patologia , Adulto , Feminino , Humanos , Leucoencefalopatias/genética , Macrófagos/citologia , Masculino , Mutação/genética , Neuroglia/citologia
17.
Eur J Hum Genet ; 23(12): 1684-8, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25873011

RESUMO

Mutations of FLNA, an X-linked gene that encodes the cytoskeletal protein filamin A, cause diverse and distinct phenotypes including periventricular nodular heterotopia and otopalatodigital spectrum disorders (OPDS). Craniofacial abnormalities associated with OPDS include supraorbital hyperostosis, down-slanting palpebral fissures and micrognathia; craniosynostosis was previously described in association with FLNA mutations in two individual case reports. Here we present four further OPDS subjects who have pathological FLNA variants and craniosynostosis, supporting a causal link. Together with the previously reported patients, frontometaphyseal dysplasia was the most common clinical diagnosis (four of six cases overall); five patients had multiple suture synostosis with the sagittal suture being the most frequently involved (also five patients). No genotype-phenotype correlation was evident in the distribution of FLNA mutations. This report highlights the need to consider a filaminopathy in the differential diagnosis of craniosynostosis, especially in the presence of atypical cranial or skeletal features.


Assuntos
Craniossinostoses/genética , Filaminas/genética , Mutação de Sentido Incorreto , Criança , Pré-Escolar , Craniossinostoses/diagnóstico , Diagnóstico Diferencial , Feminino , Humanos , Lactente , Masculino , Fenótipo
18.
Am J Hum Genet ; 96(3): 462-73, 2015 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-25683120

RESUMO

Freeman-Sheldon syndrome, or distal arthrogryposis type 2A (DA2A), is an autosomal-dominant condition caused by mutations in MYH3 and characterized by multiple congenital contractures of the face and limbs and normal cognitive development. We identified a subset of five individuals who had been putatively diagnosed with "DA2A with severe neurological abnormalities" and for whom congenital contractures of the limbs and face, hypotonia, and global developmental delay had resulted in early death in three cases; this is a unique condition that we now refer to as CLIFAHDD syndrome. Exome sequencing identified missense mutations in the sodium leak channel, non-selective (NALCN) in four families affected by CLIFAHDD syndrome. We used molecular-inversion probes to screen for NALCN in a cohort of 202 distal arthrogryposis (DA)-affected individuals as well as concurrent exome sequencing of six other DA-affected individuals, thus revealing NALCN mutations in ten additional families with "atypical" forms of DA. All 14 mutations were missense variants predicted to alter amino acid residues in or near the S5 and S6 pore-forming segments of NALCN, highlighting the functional importance of these segments. In vitro functional studies demonstrated that NALCN alterations nearly abolished the expression of wild-type NALCN, suggesting that alterations that cause CLIFAHDD syndrome have a dominant-negative effect. In contrast, homozygosity for mutations in other regions of NALCN has been reported in three families affected by an autosomal-recessive condition characterized mainly by hypotonia and severe intellectual disability. Accordingly, mutations in NALCN can cause either a recessive or dominant condition characterized by varied though overlapping phenotypic features, perhaps based on the type of mutation and affected protein domain(s).


Assuntos
Contratura/genética , Extremidades/fisiopatologia , Face/anormalidades , Hipotonia Muscular/genética , Canais de Sódio/genética , Artrogripose/genética , Disostose Craniofacial/genética , Proteínas do Citoesqueleto/genética , Proteínas do Citoesqueleto/metabolismo , Exoma , Feminino , Frequência do Gene , Sequenciamento de Nucleotídeos em Larga Escala , Homozigoto , Humanos , Lactente , Masculino , Mutação de Sentido Incorreto , Canais de Sódio/metabolismo
19.
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
20.
Neuromuscul Disord ; 25(2): 138-40, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25466363

RESUMO

Heat-induced CNS injury has been recognized for more than 50 years but the biological basis for the marked selectivity of CNS damage is currently uncertain. We present clinical, imaging, autopsy and genetic findings of a 14-year-old male who developed fatal cerebellar swelling in the course of a malignant hyperthermia (MH) episode caused by triggering anaesthetics. Unaccustomed intense exercise in the days prior to general anaesthesia was a probable confounding factor for the MH reaction. Autopsy findings demonstrated pronounced degeneration of cerebellar Purkinje cells. Post mortem genetic analysis revealed a mutation (c.6502G>A; p.Val2168Met) in the skeletal muscle ryanodine receptor (RYR1) gene previously associated with the MH trait. RYR1 mutations appear to be associated with heat-induced CNS injury in a distribution compatible with known expression pattern of the RyR1 isoform in cerebellar Purkinje cells. Recent exercise in genetically predisposed individuals may prime abnormal muscle prior to general anaesthesia and contribute to the severity of MH reactions.


Assuntos
Cerebelo/patologia , Febre/genética , Febre/patologia , Mutação/genética , Canal de Liberação de Cálcio do Receptor de Rianodina/genética , Adolescente , Apendicectomia , Humanos , Imagem por Ressonância Magnética , Masculino
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