Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 13 de 13
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Nat Commun ; 10(1): 3094, 2019 07 12.
Artigo em Inglês | MEDLINE | ID: mdl-31300657

RESUMO

AMPA receptors (AMPARs) are tetrameric ligand-gated channels made up of combinations of GluA1-4 subunits encoded by GRIA1-4 genes. GluA2 has an especially important role because, following post-transcriptional editing at the Q607 site, it renders heteromultimeric AMPARs Ca2+-impermeable, with a linear relationship between current and trans-membrane voltage. Here, we report heterozygous de novo GRIA2 mutations in 28 unrelated patients with intellectual disability (ID) and neurodevelopmental abnormalities including autism spectrum disorder (ASD), Rett syndrome-like features, and seizures or developmental epileptic encephalopathy (DEE). In functional expression studies, mutations lead to a decrease in agonist-evoked current mediated by mutant subunits compared to wild-type channels. When GluA2 subunits are co-expressed with GluA1, most GRIA2 mutations cause a decreased current amplitude and some also affect voltage rectification. Our results show that de-novo variants in GRIA2 can cause neurodevelopmental disorders, complementing evidence that other genetic causes of ID, ASD and DEE also disrupt glutamatergic synaptic transmission.


Assuntos
Deficiência Intelectual/genética , Transtornos do Neurodesenvolvimento/genética , Receptores de AMPA/genética , Adolescente , Adulto , Encéfalo/diagnóstico por imagem , Criança , Pré-Escolar , Estudos de Coortes , Feminino , Heterozigoto , Humanos , Lactente , Mutação com Perda de Função , Imagem por Ressonância Magnética , Masculino , Transtornos do Neurodesenvolvimento/diagnóstico por imagem , Adulto Jovem
2.
Bone ; 121: 163-171, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30599297

RESUMO

Heterozygous pathogenic variants in the FN1 gene, encoding fibronectin (FN), have recently been shown to be associated with a skeletal disorder in some individuals affected by spondylometaphyseal dysplasia with "corner fractures" (SMD-CF). The most striking feature characterizing SMD-CF is irregularly shaped metaphyses giving the appearance of "corner fractures". An array of secondary features, including developmental coxa vara, ovoid vertebral bodies and severe scoliosis, may also be present. FN is an important extracellular matrix component for bone and cartilage development. Here we report five patients affected by this subtype of SMD-CF caused by five novel FN1 missense mutations: p.Cys123Tyr, p.Cys169Tyr, p.Cys213Tyr, p.Cys231Trp and p.Cys258Tyr. All individuals shared a substitution of a cysteine residue, disrupting disulfide bonds in the FN type-I assembly domains located in the N-terminal assembly region. The abnormal metaphyseal ossification and "corner fracture" appearances were the most remarkable clinical feature in these patients. In addition, generalized skeletal fragility with low-trauma bilateral femoral fractures was identified in one patient. Interestingly, the distal femoral changes in this patient healed with skeletal maturation. Our report expands the phenotypic and genetic spectrum of the FN1-related SMD-CF and emphasizes the importance of FN in bone formation and possibly also in the maintenance of bone strength.

3.
Am J Hum Genet ; 104(2): 287-298, 2019 02 07.
Artigo em Inglês | MEDLINE | ID: mdl-30661771

RESUMO

Hypusine is formed post-translationally from lysine and is found in a single cellular protein, eukaryotic translation initiation factor-5A (eIF5A), and its homolog eIF5A2. Biosynthesis of hypusine is a two-step reaction involving the enzymes deoxyhypusine synthase (DHPS) and deoxyhypusine hydroxylase (DOHH). eIF5A is highly conserved throughout eukaryotic evolution and plays a role in mRNA translation, cellular proliferation, cellular differentiation, and inflammation. DHPS is also highly conserved and is essential for life, as Dhps-null mice are embryonic lethal. Using exome sequencing, we identified rare biallelic, recurrent, predicted likely pathogenic variants in DHPS segregating with disease in five affected individuals from four unrelated families. These individuals have similar neurodevelopmental features that include global developmental delay and seizures. Two of four affected females have short stature. All five affected individuals share a recurrent missense variant (c.518A>G [p.Asn173Ser]) in trans with a likely gene disrupting variant (c.1014+1G>A, c.912_917delTTACAT [p.Tyr305_Ile306del], or c.1A>G [p.Met1?]). cDNA studies demonstrated that the c.1014+1G>A variant causes aberrant splicing. Recombinant DHPS enzyme harboring either the p.Asn173Ser or p.Tyr305_Ile306del variant showed reduced (20%) or absent in vitro activity, respectively. We co-transfected constructs overexpressing HA-tagged DHPS (wild-type or mutant) and GFP-tagged eIF5A into HEK293T cells to determine the effect of these variants on hypusine biosynthesis and observed that the p.Tyr305_Ile306del and p.Asn173Ser variants resulted in reduced hypusination of eIF5A compared to wild-type DHPS enzyme. Our data suggest that rare biallelic variants in DHPS result in reduced enzyme activity that limits the hypusination of eIF5A and are associated with a neurodevelopmental disorder.


Assuntos
Genes Recessivos/genética , Lisina/análogos & derivados , Mutação , Transtornos do Neurodesenvolvimento/enzimologia , Transtornos do Neurodesenvolvimento/genética , Oxirredutases atuantes sobre Doadores de Grupo CH-NH/genética , Alelos , Sequência de Aminoácidos , Criança , Pré-Escolar , Deficiências do Desenvolvimento/enzimologia , Deficiências do Desenvolvimento/genética , Feminino , Haplótipos , Humanos , Lisina/biossíntese , Masculino , Erros Inatos do Metabolismo/enzimologia , Erros Inatos do Metabolismo/genética , Oxirredutases atuantes sobre Doadores de Grupo CH-NH/química , Oxirredutases atuantes sobre Doadores de Grupo CH-NH/metabolismo , Linhagem , Fatores de Iniciação de Peptídeos/química , Fatores de Iniciação de Peptídeos/metabolismo , Proteínas de Ligação a RNA/química , Proteínas de Ligação a RNA/metabolismo , Convulsões/enzimologia , Convulsões/genética , Adulto Jovem
4.
PLoS Genet ; 14(11): e1007671, 2018 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-30500825

RESUMO

Mutations that alter signaling of RAS/MAPK-family proteins give rise to a group of Mendelian diseases known as RASopathies. However, among RASopathies, the matrix of genotype-phenotype relationships is still incomplete, in part because there are many RAS-related proteins and in part because the phenotypic consequences may be variable and/or pleiotropic. Here, we describe a cohort of ten cases, drawn from six clinical sites and over 16,000 sequenced probands, with de novo protein-altering variation in RALA, a RAS-like small GTPase. All probands present with speech and motor delays, and most have intellectual disability, low weight, short stature, and facial dysmorphism. The observed rate of de novo RALA variants in affected probands is significantly higher (p = 4.93 x 10-11) than expected from the estimated random mutation rate. Further, all de novo variants described here affect residues within the GTP/GDP-binding region of RALA; in fact, six alleles arose at only two codons, Val25 and Lys128. The affected residues are highly conserved across both RAL- and RAS-family genes, are devoid of variation in large human population datasets, and several are homologous to positions at which disease-associated variants have been observed in other GTPase genes. We directly assayed GTP hydrolysis and RALA effector-protein binding of the observed variants, and found that all but one tested variant significantly reduced both activities compared to wild-type. The one exception, S157A, reduced GTP hydrolysis but significantly increased RALA-effector binding, an observation similar to that seen for oncogenic RAS variants. These results show the power of data sharing for the interpretation and analysis of rare variation, expand the spectrum of molecular causes of developmental disability to include RALA, and provide additional insight into the pathogenesis of human disease caused by mutations in small GTPases.

5.
Am J Med Genet C Semin Med Genet ; 178(1): 46-53, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29675991

RESUMO

The skill sets of genetic counselors are strongly utilized in industry, as evidenced by 20% of genetic counselors reporting employment within industry in 2016. In addition, industry genetic counselors are expanding their roles, taking on new responsibilities, and creating new opportunities. These advances have impacted the profession as a whole including, but not limited to, genetic counseling training curricula, a shift back to genetic counseling directly to patients, and a growing influence of genetic counselors on industry test offerings. Industry genetic counselors and training programs are working together to address the challenges and opportunities presented by workforce changes and novel interpretations of how genetic counselors' core competencies can be utilized. Counseling of patients by industry genetic counselors has become more commonplace and addresses a need for alternate service delivery models. Industry genetic counselors often provide significant contributions to test development, education, marketing, and interpretation. Beyond these broad examples, individual industry genetic counselors have created unique niches for themselves, using their genetic counseling training combined with unique opportunities offered through industry, as illustrated by genetic counselors' various roles and responsibilities highlighted here.

6.
Am J Hum Genet ; 102(5): 744-759, 2018 05 03.
Artigo em Inglês | MEDLINE | ID: mdl-29656859

RESUMO

RORα, the RAR-related orphan nuclear receptor alpha, is essential for cerebellar development. The spontaneous mutant mouse staggerer, with an ataxic gait caused by neurodegeneration of cerebellar Purkinje cells, was discovered two decades ago to result from homozygous intragenic Rora deletions. However, RORA mutations were hitherto undocumented in humans. Through a multi-centric collaboration, we identified three copy-number variant deletions (two de novo and one dominantly inherited in three generations), one de novo disrupting duplication, and nine de novo point mutations (three truncating, one canonical splice site, and five missense mutations) involving RORA in 16 individuals from 13 families with variable neurodevelopmental delay and intellectual disability (ID)-associated autistic features, cerebellar ataxia, and epilepsy. Consistent with the human and mouse data, disruption of the D. rerio ortholog, roraa, causes significant reduction in the size of the developing cerebellum. Systematic in vivo complementation studies showed that, whereas wild-type human RORA mRNA could complement the cerebellar pathology, missense variants had two distinct pathogenic mechanisms of either haploinsufficiency or a dominant toxic effect according to their localization in the ligand-binding or DNA-binding domains, respectively. This dichotomous direction of effect is likely relevant to the phenotype in humans: individuals with loss-of-function variants leading to haploinsufficiency show ID with autistic features, while individuals with de novo dominant toxic variants present with ID, ataxia, and cerebellar atrophy. Our combined genetic and functional data highlight the complex mutational landscape at the human RORA locus and suggest that dual mutational effects likely determine phenotypic outcome.

7.
Artigo em Inglês | MEDLINE | ID: mdl-29162653

RESUMO

Using whole-exome sequencing, we identified seven unrelated individuals with global developmental delay, hypotonia, dysmorphic facial features, and an increased frequency of short stature, ataxia, and autism with de novo heterozygous frameshift, nonsense, splice, and missense variants in the Early B-cell Transcription Factor Family Member 3 (EBF3) gene. EBF3 is a member of the collier/olfactory-1/early B-cell factor (COE) family of proteins, which are required for central nervous system (CNS) development. COE proteins are highly evolutionarily conserved and regulate neuronal specification, migration, axon guidance, and dendritogenesis during development and are essential for maintaining neuronal identity in adult neurons. Haploinsufficiency of EBF3 may affect brain development and function, resulting in developmental delay, intellectual disability, and behavioral differences observed in individuals with a deleterious variant in EBF3.


Assuntos
Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Adolescente , Sequência de Aminoácidos/genética , Ataxia/genética , Transtorno Autístico/genética , Criança , Pré-Escolar , Sequência Conservada/genética , Deficiências do Desenvolvimento/genética , Exoma , Feminino , Humanos , Lactente , Deficiência Intelectual , Masculino , Hipotonia Muscular/genética , Mutação , Transtornos do Neurodesenvolvimento/genética , Síndrome de Prader-Willi/genética , Sequenciamento Completo do Exoma/métodos , Adulto Jovem
8.
Hum Mol Genet ; 26(24): 4937-4950, 2017 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-29040572

RESUMO

Iron-sulfur (Fe-S) clusters are ubiquitous cofactors essential to various cellular processes, including mitochondrial respiration, DNA repair, and iron homeostasis. A steadily increasing number of disorders are being associated with disrupted biogenesis of Fe-S clusters. Here, we conducted whole-exome sequencing of patients with optic atrophy and other neurological signs of mitochondriopathy and identified 17 individuals from 13 unrelated families with recessive mutations in FDXR, encoding the mitochondrial membrane-associated flavoprotein ferrodoxin reductase required for electron transport from NADPH to cytochrome P450. In vitro enzymatic assays in patient fibroblast cells showed deficient ferredoxin NADP reductase activity and mitochondrial dysfunction evidenced by low oxygen consumption rates (OCRs), complex activities, ATP production and increased reactive oxygen species (ROS). Such defects were rescued by overexpression of wild-type FDXR. Moreover, we found that mice carrying a spontaneous mutation allelic to the most common mutation found in patients displayed progressive gait abnormalities and vision loss, in addition to biochemical defects consistent with the major clinical features of the disease. Taken together, these data provide the first demonstration that germline, hypomorphic mutations in FDXR cause a novel mitochondriopathy and optic atrophy in humans.


Assuntos
Ferredoxinas/genética , Atrofia Óptica/genética , Sulfito Redutase (Ferredoxina)/genética , Adolescente , Alelos , Animais , Criança , Pré-Escolar , Transporte de Elétrons , Feminino , Ferredoxinas/metabolismo , Humanos , Lactente , Ferro/metabolismo , Proteínas com Ferro-Enxofre/genética , Masculino , Camundongos , Mitocôndrias/genética , Mitocôndrias/metabolismo , Membranas Mitocondriais/metabolismo , Mutagênese , Mutação , Oxirredutases/genética , Oxirredutases/metabolismo , Linhagem , Sulfito Redutase (Ferredoxina)/metabolismo , Sequenciamento Completo do Exoma/métodos
9.
Ann Neurol ; 82(3): 466-478, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28856709

RESUMO

OBJECTIVE: Rett syndrome (RTT) and epileptic encephalopathy (EE) are devastating neurodevelopmental disorders with distinct diagnostic criteria. However, highly heterogeneous and overlapping clinical features often allocate patients into the boundary of the two conditions, complicating accurate diagnosis and appropriate medical interventions. Therefore, we investigated the specific molecular mechanism that allows an understanding of the pathogenesis and relationship of these two conditions. METHODS: We screened novel genetic factors from 34 RTT-like patients without MECP2 mutations, which account for ∼90% of RTT cases, by whole-exome sequencing. The biological function of the discovered variants was assessed in cell culture and Xenopus tropicalis models. RESULTS: We identified a recurring de novo variant in GABAB receptor R2 (GABBR2) that reduces the receptor function, whereas different GABBR2 variants in EE patients possess a more profound effect in reducing receptor activity and are more responsive to agonist rescue in an animal model. INTERPRETATION: GABBR2 is a genetic factor that determines RTT- or EE-like phenotype expression depending on the variant positions. GABBR2-mediated γ-aminobutyric acid signaling is a crucial factor in determining the severity and nature of neurodevelopmental phenotypes. Ann Neurol 2017;82:466-478.


Assuntos
Mutação , Receptores de GABA-B/genética , Síndrome de Rett/genética , Espasmos Infantis/genética , Exoma , Genótipo , Células HEK293 , Humanos , Proteína 2 de Ligação a Metil-CpG/genética , Fenótipo , Transdução de Sinais/genética
10.
Am J Hum Genet ; 100(3): 537-545, 2017 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-28190459

RESUMO

Congenital muscular dystrophies display a wide phenotypic and genetic heterogeneity. The combination of clinical, biochemical, and molecular genetic findings must be considered to obtain the precise diagnosis and provide appropriate genetic counselling. Here we report five individuals from four families presenting with variable clinical features including muscular dystrophy with a reduction in dystroglycan glycosylation, short stature, intellectual disability, and cataracts, overlapping both the dystroglycanopathies and Marinesco-Sjögren syndrome. Whole-exome sequencing revealed homozygous missense and compound heterozygous mutations in INPP5K in the affected members of each family. INPP5K encodes the inositol polyphosphate-5-phosphatase K, also known as SKIP (skeletal muscle and kidney enriched inositol phosphatase), which is highly expressed in the brain and muscle. INPP5K localizes to both the endoplasmic reticulum and to actin ruffles in the cytoplasm. It has been shown to regulate myoblast differentiation and has also been implicated in protein processing through its interaction with the ER chaperone HSPA5/BiP. We show that morpholino-mediated inpp5k loss of function in the zebrafish results in shortened body axis, microphthalmia with disorganized lens, microcephaly, reduced touch-evoked motility, and highly disorganized myofibers. Altogether these data demonstrate that mutations in INPP5K cause a congenital muscular dystrophy syndrome with short stature, cataracts, and intellectual disability.


Assuntos
Distrofia Muscular do Cíngulo dos Membros/genética , Monoéster Fosfórico Hidrolases/genética , Degenerações Espinocerebelares/genética , Adolescente , Adulto , Sequência de Aminoácidos , Animais , Encéfalo/metabolismo , Criança , Modelos Animais de Doenças , Distroglicanas/metabolismo , Retículo Endoplasmático/metabolismo , Feminino , Estudo de Associação Genômica Ampla , Glicosilação , Transtornos do Crescimento/genética , Humanos , Deficiência Intelectual/genética , Masculino , Microcefalia/genética , Músculo Esquelético/metabolismo , Mutação , Linhagem , Adulto Jovem , Peixe-Zebra/genética
11.
Hum Genet ; 135(7): 699-705, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-27048600

RESUMO

Whole exome sequencing (WES) can be used to efficiently identify de novo genetic variants associated with genetically heterogeneous conditions including intellectual disabilities. We have performed WES for 4102 (1847 female; 2255 male) intellectual disability/developmental delay cases and we report five patients with a neurodevelopmental disorder associated with developmental delay, intellectual disability, behavioral problems, hypotonia, speech problems, microcephaly, pachygyria and dysmorphic features in whom we have identified de novo missense and canonical splice site mutations in CSNK2A1, the gene encoding CK2α, the catalytic subunit of protein kinase CK2, a ubiquitous serine/threonine kinase composed of two regulatory (ß) and two catalytic (α and/or α') subunits. Somatic mutations in CSNK2A1 have been implicated in various cancers; however, this is the first study to describe a human condition associated with germline mutations in any of the CK2 subunits.


Assuntos
Transtornos Dismórficos Corporais/genética , Deficiência Intelectual/genética , Transtornos do Neurodesenvolvimento/genética , Adolescente , Transtornos Dismórficos Corporais/fisiopatologia , Caseína Quinase II/genética , Criança , Pré-Escolar , Exoma/genética , Feminino , Predisposição Genética para Doença , Mutação em Linhagem Germinativa , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Deficiência Intelectual/patologia , Mutação , Transtornos do Neurodesenvolvimento/fisiopatologia
12.
Int Arch Allergy Immunol ; 139(3): 217-24, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16446545

RESUMO

BACKGROUND: CD14 promoter DNA sequence polymorphisms for the endotoxin receptor gene have been implicated in modulating allergen-specific immunoglobulin (Ig)E responses in randomly selected individuals with atopy. We sought to determine if a single nucleotide polymorphism in the CD14 promoter region is associated with atopy in atopic families, and to assess its influence on serum levels of CD14 and allergen-specific IgE and IgG1 responses. METHODS: We screened 367 members of 91 Caucasian nuclear families with a history of asthma for pulmonary function by spirometry, including methacholine challenge to detect bronchial hyperreactivity, and atopy by serum total IgE and skin prick test to 14 allergens. The CD14 promoter single nucleotide polymorphism was analyzed in DNA isolated from peripheral blood mononuclear cells to identify C/C, C/T and T/T genotypes. Serum tests were done for soluble CD14 (sCD14) and dust mite-specific antibody (Der p 1-IgG1). RESULTS: Serum sCD14 levels were not associated with clinical phenotypes (asthma, bronchial hyperreactivity or atopy). However, sCD14 levels were inversely related to both allergen-specific IgE and Der p 1-IgG1 production, but only among those with evidence of atopic sensitization. Linear regression analysis, accounting for random family effects, demonstrated a higher production of allergen-specific IgE or Der p 1-IgG1 associated with the T/T genotype and a lower level of specific IgE and IgG1 production associated with sCD14 levels. CONCLUSIONS: An element of the innate immune system (CD14) has profound effects upon modulating the acquired allergen-specific immunoglobulin responses among those with an inherited atopic predisposition.


Assuntos
Alérgenos/imunologia , Asma/genética , Asma/imunologia , Imunoglobulina E/imunologia , Imunoglobulina G/imunologia , Receptores de Lipopolissacarídeos/genética , Receptores de Lipopolissacarídeos/imunologia , Adolescente , Adulto , Idoso , Antígenos de Dermatophagoides/sangue , Antígenos de Dermatophagoides/imunologia , Proteínas de Artrópodes , Criança , Cisteína Endopeptidases , Feminino , Predisposição Genética para Doença , Humanos , Imunoglobulina E/sangue , Imunoglobulina G/sangue , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único , Regiões Promotoras Genéticas , Testes Cutâneos
13.
Am J Hum Genet ; 73(3): 638-45, 2003 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-12876664

RESUMO

The heterogeneous group of disorders known as oculocutaneous albinism (OCA) shares cutaneous and ocular hypopigmentation associated with common developmental abnormalities of the eye. Mutations of at least 11 loci produce this phenotype. The majority of affected individuals develop some cutaneous melanin; this is predominantly seen as yellow/blond hair, whereas fewer have brown hair. The OCA phenotype is dependent on the constitutional pigmentation background of the family, with more OCA pigmentation found in families with darker constitutional pigmentation, which indicates that other genes may modify the OCA phenotype. Sequence variation in the melanocortin-1 receptor (MC1R) gene is associated with red hair in the normal population, but red hair is unusual in OCA. We identified eight probands with OCA who had red hair at birth. Mutations in the P gene were responsible for classic phenotype of oculocutaneous albinism type 2 (OCA2) in all eight, and mutations in the MC1R gene were responsible for the red (rather than yellow/blond) hair in the six of eight who continued to have red hair after birth. This is the first demonstration of a gene modifying the OCA phenotype in humans.


Assuntos
Receptores da Corticotropina/genética , Adolescente , Adulto , Albinismo Oculocutâneo , Pré-Escolar , Feminino , Cor de Cabelo/genética , Humanos , Lactente , Masculino , Mutação , Linhagem , Fenótipo , Receptores de Melanocortina
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA