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1.
Artigo em Chinês | MEDLINE | ID: mdl-33040498

RESUMO

Objective:To explore the genetic cause of a Chinese autosomal dominant nonsyndromic hearing loss family and investigate the clinical features and molecular genetic characteristics of this family. Method:Detailed medical history and systematic audiology tests were carried out in the family members, and they were subjected to comprehensive genetic analyses using massively parallel sequencing, which targeted 139 known deafness genes and 6 mitochondrial DNA mutations associated with hearing loss. Result:This family's hearing loss was consistent with autosomal dominant nonsyndromic hearing loss. The affected family members appeared to have developed a high-frequency hearing loss with the onset of twenties. We identified a heterozygous missense mutation, c.418A>G/p. Thr140Ala in the CEACAM16 gene, segregating with the deafness in this family. Conclusion:In this study, we identified a new mutation of CEACAM16 gene, which was the second mutation identified in Chinese hearing loss population. It has enriched the mutation spectrum of this gene.


Assuntos
Artrogripose , Surdez , Moléculas de Adesão Celular , Surdez/genética , Humanos , Mutação , Linhagem
2.
Beijing Da Xue Xue Bao Yi Xue Ban ; 52(5): 836-844, 2020 Oct 18.
Artigo em Chinês | MEDLINE | ID: mdl-33047716

RESUMO

OBJECTIVE: To evaluate and compare whole exome sequencing (WES) and targeted panel sequencing in the clinical molecular diagnosis of the Chinese families affected with inherited retinal dystrophies (IRDs). METHODS: The clinical information of 182 probands affected with IRDs was collected, including their family history and the ophthalmic examination results. Blood samples of all probands and their relatives were collected and genomic DNA was extracted by standard protocols. The first 91 cases were subjected to the WES and the other 91 cases were subjected to a specific hereditary eye disease enrichment panel (HEDEP) designed by us. All likely pathogenic and pathogenic variants in the candidate genes were determined by Sanger sequencing and co-segregation analyses were performed in available family members. Copy number variations (CNVs) detected by HEDEP were further validated by multiplex ligation-dependent probe amplification (MLPA). As PRGR ORF15 was difficult to capture by next generation sequencing (NGS), all the samples were subjected to Sanger sequencing for this region. All sequence changes identified by NGS were classified according to the American College of Medical Gene-tics and Genomics and the Association for Molecular Pathology (ACMG/AMP) variant interpretation guidelines. In this study, only variants identified as pathogenic or likely pathogenic were included, while those variants of uncertain significance, likely benign or benign were not included. RESULTS: In 91 cases with WES, pathogenic or likely pathogenic variants were determined in 30 cases, obtaining a detection rate of 33.00% (30/91); While in 91 cases with HEDEP sequencing, pathogenic or likely pathogenic variants were determined in 51 cases, achieving the diagnostic rate of 56.04% (51/91), and totally, the diagnostic rate was 44.51%. HEDEP had better sequencing coverage and read depth than WES, therefore HEDEP had higher detection rate. In addition, HEDEP could detect CNVs. In this study, we detected disease-causing variants in 29 distinct IRD-associated genes, USH2A, ABCA4 and RPGR were the three most common disease-causing genes, and the frequency of these genes in Chinese IRDs population was 11.54% (21/182), 6.59% (12/182) and 3.85% (7/182), respectively. We found 43 novel variants and 6 cases carried variants in RPGR ORF15. CONCLUSION: NGS in conjunction with Sanger sequencing offers a reliable and effective approach for the genetic diagnosis of IRDs, and after evaluating the pros and cons of the two sequencing methods, we conclude that HEDEP should be used as a first-tier test for IRDs patients, WES can be used as a supplementary molecular diagnostic method due to its merit of detecting novel IRD-associated genes if HEDEP or other methods could not detect disease-causing va-riants in reported genes. In addition, our results enriched the mutational spectra of IRDs genes, and our methods paves the way of genetic counselling, family planning and up-coming gene-based therapies for these families.


Assuntos
Variações do Número de Cópias de DNA , Distrofias Retinianas , Humanos , Mutação , Linhagem , Distrofias Retinianas/diagnóstico , Distrofias Retinianas/genética , Sequenciamento Completo do Exoma
3.
Virulence ; 11(1): 1240-1249, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-32930632

RESUMO

Eight members of a big family with laboratory-confirmed COVID-19 pneumonia were admitted to First Hospital of Jilin University, Changchun, China, from 28 January to 5 February 2020. The clinical records, laboratory results, and chest computed tomography (CT) scans were retrospectively reviewed. Throat swab samples were positive for severe acute respiratory syndrome coronavirus 2, confirmed by the Center for Disease Control and Prevention of Changchun. All eight patients had fever of different degrees; and 6, 3, and 2 had cough; diarrhea; and sore throat. With disease progression, the percentage of lymphocytes in older patients increased, CT images worsened, and the ratio of lymphocytes increased when images revealed inflammation absorption. Although the CT images showed ground-glass opacities in the youngest patient, his lymphocyte count did not decrease with mild clinical symptoms, and the images showed that inflammation was quickly absorbed. Only the oldest patient developed critical illness. The C reaction protein (CRP) levels of Patient 5 increased significantly, and the rate of decline was the slowest, while his condition was the most severe. The clinical manifestations of COVID-19 in this family cluster varied with contact, age, and underlying disease. Lymphocyte count and quality of chest CT images appeared inversely associated with disease severity. CRP changes may be an indicator of disease severity and prognosis.


Assuntos
Betacoronavirus , Técnicas de Laboratório Clínico , Infecções por Coronavirus/diagnóstico , Infecções por Coronavirus/transmissão , Pneumonia Viral/diagnóstico , Pneumonia Viral/transmissão , Adulto , Idoso , Idoso de 80 Anos ou mais , Betacoronavirus/patogenicidade , China/epidemiologia , Infecções por Coronavirus/epidemiologia , Família , Feminino , Humanos , Pulmão/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Pandemias , Linhagem , Pneumonia Viral/epidemiologia , Estudos Retrospectivos , Fatores de Tempo , Tomografia Computadorizada por Raios X , Virulência
5.
Vestn Otorinolaringol ; 85(4): 65-69, 2020.
Artigo em Russo | MEDLINE | ID: mdl-32885640

RESUMO

Congenital hearing loss is one of the most frequent inherited human pathologies, occurring in 1-2 out of 1000 newborns. X-linked hearing loss occurs in 1-5% of all congenital hearing impairments. The proband (a man) and his affected brother have profound prelingual non-syndromic neurosensory hearing loss. Their parents are healthy. The aim of the study was to determine the cause of hearing loss in a given family and to assess the population frequency of the revealed pathogenic genetic variant. NGS analysis identified a pathogenic variant c.907C>T (p.Pro303Ser) in the POU3F4 gene mapped to the Xq21.1 locus. This is the second case of X-linked hearing loss (DFNX2, OMIM 304400) in Europe, caused by the c.907C>T variant in the POU3F4 gene. DFNX2-hearing loss is manifested with abnormalities of the inner ear, predisposing to the "gusher effect" - otoliquorrhea during stapedoplasty. The brother was diagnosed with a c.907C>T variant in the POU3F4 gene in the hemizygous state while in their mother - in the heterozygous state. Their father had no variant c.907C>T. Molecular genetic analysis showed that the genetic variant c.907C>T was not detected in the control sample of healthy female from the Nogai population, which suggests its low frequency in the population.


Assuntos
Perda Auditiva Neurossensorial , Perda Auditiva , Europa (Continente) , Feminino , Humanos , Recém-Nascido , Masculino , Fatores do Domínio POU/genética , Linhagem
6.
Int Heart J ; 61(5): 1049-1055, 2020 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-32921676

RESUMO

While a KCND3 V392I mutation uniquely displays a mixed electrophysiological phenotype of Kv4.3, only limited clinical information on the mutation carriers is available. We report two teenage siblings exhibiting both cardiac (early repolarization syndrome and paroxysmal atrial fibrillation) and cerebral phenotypes (epilepsy and intellectual disability), in whom we identified the KCND3 V392I mutation. We propose a link between the KCND3 mutation with a mixed electrophysiological phenotype and cardiocerebral phenotypes, which may be defined as a novel cardiocerebral channelopathy.


Assuntos
Fibrilação Atrial/genética , Canalopatias/genética , Epilepsias Parciais/genética , Deficiência Intelectual/genética , Canais de Potássio Shal/genética , Adolescente , Morte Súbita Cardíaca , Eletrocardiografia , Eletroencefalografia , Feminino , Humanos , Pessoa de Meia-Idade , Mães , Mutação , Linhagem , Irmãos , Síncope/genética , Adulto Jovem
7.
Medicine (Baltimore) ; 99(31): e21438, 2020 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-32756155

RESUMO

RATIONALE: Mutations in the hepatocyte nuclear factor-1-beta (HNF1B) gene result in a very variable presentation, including maturity onset diabetes of the young (MODY), renal cysts, renal dysplasia, and autosomal dominant tubulointerstitial kidney disease (ADTKD), which is characterized by tubular damage, renal fibrosis, and progressive renal dysfunction. PATIENT CONCERNS: A 22-year-old man came to the hospital presenting with hyperglycemia, hyperuricemia and elevated serum creatinine. His urine protein was within the normal range. The ultrasound examination revealed shrunken kidneys with renal cysts. The patient's mother was diagnosed with diabetes mellitus when she was 25 years old. Her laboratory results showed elevated serum creatinine. Her ultrasonography revealed shrunken kidneys with renal cysts and hydronephrosis without kidney stones. The next-generation sequencing revealed that the proband and his mother held the same heterozygous missense mutation (c.530G>A, NM_000458, p.R177Q) in the HNF1B gene. Bioinformatic analyses predicted that the mutation was likely pathogenic. DIAGNOSIS: The patient and his mother were diagnosed as ADTKD and MODY5 due to HNF1B mutation. INTERVENTION: The proband was administered metformin at a dose of 500 mg/day. OUTCOMES: The patient had well-controlled blood glucose levels and a stable renal function at his 12-month follow-up. LESSONS: We should take into account the diagnoses of ADTKD and MODY5 if patients present with early onset diabetes and multiple renal cysts or evidence of renal tubulointerstitial dysplasia, especially those with negative proteinuria results. Genetic testing helps detect the HNF1B gene mutations.


Assuntos
Doenças do Sistema Nervoso Central/genética , Esmalte Dentário/anormalidades , Diabetes Mellitus Tipo 2/genética , Fator 1-beta Nuclear de Hepatócito/genética , Doenças Renais Císticas/genética , Nefrite Intersticial/genética , Assistência ao Convalescente , Doenças do Sistema Nervoso Central/complicações , Doenças do Sistema Nervoso Central/tratamento farmacológico , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/tratamento farmacológico , Heterozigoto , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Humanos , Hiperglicemia/etiologia , Hiperuricemia/etiologia , Hipoglicemiantes/administração & dosagem , Hipoglicemiantes/uso terapêutico , Rim/diagnóstico por imagem , Rim/patologia , Rim/fisiopatologia , Doenças Renais Císticas/complicações , Doenças Renais Císticas/tratamento farmacológico , Doenças Renais Císticas/patologia , Masculino , Metformina/administração & dosagem , Metformina/uso terapêutico , Mutação de Sentido Incorreto , Nefrite Intersticial/complicações , Nefrite Intersticial/patologia , Linhagem , Ultrassonografia/métodos , Adulto Jovem
8.
Medicine (Baltimore) ; 99(34): e21797, 2020 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-32846814

RESUMO

LMNA gene encodes Lamin A and C (Lamin A/C), which are intermediate filament protein implicating in DNA replication and transcription. Mutations in LMNA are validated to cause cardiac conduction disease (CCD) and cardiomyopathy.In a Chinese family, we identified 5 members harboring the identical heterozygous LMNA (c.686T>C, I229T) disease-causing mutation, which was not found in the 535 healthy controls. In silico analysis, we revealed structural alteration in Lamin A/C I229T mutant. Furthermore, molecular docking identified human polycomb repressive complex 2 and Lamin A/C interact with higher affinity in the presence of I229T, thus may downregulate Nav1.5 channel expression.Our findings expanded the spectrum of mutations associated with CCD and were valuable in the genetic diagnosis and clinical screening for CCD. Molecular docking analysis provided useful information of increased binding affinity between mutant Lamin A/C and polycomb repressive complex 2. However, the concrete mechanism of LMNA mutation (I229T) remains undetermined in our study, future genetics and molecular studies are still needed.


Assuntos
Doença do Sistema de Condução Cardíaco/genética , Lamina Tipo A/genética , Adulto , Idoso , Estudos de Casos e Controles , Análise Mutacional de DNA , Eletrocardiografia , Feminino , Heterozigoto , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Lamina Tipo A/metabolismo , Masculino , Pessoa de Meia-Idade , Simulação de Acoplamento Molecular , Mutação , Linhagem , Adulto Jovem
9.
Medicine (Baltimore) ; 99(34): e21843, 2020 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-32846832

RESUMO

RATIONALE: Hypertrophic cardiomyopathy (HCM) is an inherited myocardial disease and a common cause of sudden cardiac death, heart failure, atrial fibrillation and stroke. In families affected by HCM, genotyping is useful for identifying susceptible relatives. In the present study, we investigated the disease-causing mutations in a three-generation Chinese family with HCM using whole exome sequencing (WES). PATIENT CONCERNS: The proband, a 50-year-old man, was diagnosed with HCM at the age of 41 years. He presented with an asymmetric hypertrophic interventricular septum and a maximum interventricular septum thickness of 18.04 mm. His third elder sister, niece and daughter were also clinically affected by HCM. DIAGNOSIS: Autosomal dominant HCM. INTERVENTIONS: Seven family members, including 4 affected members, accepted WES. The genetic variants were subsequently called using Genome Analysis Toolkit and annotated using the InterVar program. Following frequency filtration by the Genome Aggregation Database, the variants were evaluated using an in-house bioinformatics analysis pipeline. OUTCOMES: HCM was transmitted as an autosomal dominant trait in the family. An extremely rare stop gained mutation, rs796925245 (g.1:201359630G>A, c.835C>T, p.Gln279Ter) in the troponin T2 (TNNT2) gene was identified as the disease-causing mutation. The stop gained mutation was predicted to result in a truncated troponin T protein in cardiac sarcomere. An adolescent family member who had normal echocardiographic measurements was found to carry the same disease-causing mutation. LESSONS: A novel nonsense TNNT2 mutation was identified as the HCM-causing mutation in this Chinese pedigree. Since HCM shows a low penetrance by clinical criteria in adolescents, the adolescent mutation carrier, who is still clinically unaffected, should be offered routine follow-ups and sport activity recommendations to prevent adverse events including sudden cardiac death in the future.


Assuntos
Cardiomiopatia Hipertrófica Familiar/genética , Troponina T/genética , Adolescente , Adulto , Idoso , Grupo com Ancestrais do Continente Asiático/genética , Cardiomiopatia Hipertrófica Familiar/complicações , Cardiomiopatia Hipertrófica Familiar/diagnóstico , Códon sem Sentido , Morte Súbita Cardíaca/etiologia , Ecocardiografia/métodos , Feminino , Humanos , Hipertrofia/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Linhagem , Fenótipo , Septo Interventricular/patologia , Sequenciamento Completo do Exoma/métodos
10.
Nat Commun ; 11(1): 4038, 2020 08 12.
Artigo em Inglês | MEDLINE | ID: mdl-32788587

RESUMO

Asparaginyl-tRNA synthetase1 (NARS1) is a member of the ubiquitously expressed cytoplasmic Class IIa family of tRNA synthetases required for protein translation. Here, we identify biallelic missense and frameshift mutations in NARS1 in seven patients from three unrelated families with microcephaly and neurodevelopmental delay. Patient cells show reduced NARS1 protein, impaired NARS1 activity and impaired global protein synthesis. Cortical brain organoid modeling shows reduced proliferation of radial glial cells (RGCs), leading to smaller organoids characteristic of microcephaly. Single-cell analysis reveals altered constituents of both astrocytic and RGC lineages, suggesting a requirement for NARS1 in RGC proliferation. Our findings demonstrate that NARS1 is required to meet protein synthetic needs and to support RGC proliferation in human brain development.


Assuntos
Aspartato-tRNA Ligase/deficiência , Aspartato-tRNA Ligase/genética , Córtex Cerebral/patologia , Microcefalia/genética , Células-Tronco Neurais/patologia , Organoides/patologia , Aminoacil-RNA de Transferência/genética , Adolescente , Adulto , Sequência de Bases , Diferenciação Celular , Proliferação de Células , Tamanho Celular , Sobrevivência Celular , Criança , Família , Feminino , Fibroblastos/metabolismo , Fibroblastos/patologia , Células HEK293 , Humanos , Células-Tronco Pluripotentes Induzidas/metabolismo , Antígeno Ki-67/metabolismo , Masculino , Mutação/genética , Células-Tronco Neurais/metabolismo , Neuroglia/metabolismo , Linhagem , Adulto Jovem
11.
PLoS Comput Biol ; 16(8): e1008065, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32797037

RESUMO

Inference of admixture proportions is a classical statistical problem in population genetics. Standard methods implicitly assume that both parents of an individual have the same admixture fraction. However, this is rarely the case in real data. In this paper we show that the distribution of admixture tract lengths in a genome contains information about the admixture proportions of the ancestors of an individual. We develop a Hidden Markov Model (HMM) framework for estimating the admixture proportions of the immediate ancestors of an individual, i.e. a type of decomposition of an individual's admixture proportions into further subsets of ancestral proportions in the ancestors. Based on a genealogical model for admixture tracts, we develop an efficient algorithm for computing the sampling probability of the genome from a single individual, as a function of the admixture proportions of the ancestors of this individual. This allows us to perform probabilistic inference of admixture proportions of ancestors only using the genome of an extant individual. We perform extensive simulations to quantify the error in the estimation of ancestral admixture proportions under various conditions. To illustrate the utility of the method, we apply it to real genetic data.


Assuntos
Genética Populacional/métodos , Avós , Pais , Linhagem , Bases de Dados Genéticas , Humanos , Funções Verossimilhança , Cadeias de Markov
14.
Proc Biol Sci ; 287(1933): 20200948, 2020 08 26.
Artigo em Inglês | MEDLINE | ID: mdl-32842928

RESUMO

To predict if a threatened species can adapt to changing selective pressures, it is crucial to understand the genetic basis of adaptive traits, especially in species historically affected by severe bottlenecks. We estimated the heritability of three hihi (Notiomystis cincta) morphological traits known to be under selection (nestling tarsus length, body mass and head-bill length) using 523 individuals and 39 699 single nucleotide polymorphisms (SNPs) from a 50 K Affymetrix SNP chip. We then examined the genetic architecture of the traits via chromosome partitioning analyses and genome-wide association scans (GWAS). Heritabilities estimated using pedigree relatedness or genomic relatedness were low. For tarsus length, the proportion of genetic variance explained by each chromosome was positively correlated with its size, and more than one chromosome explained significant variation for body mass and head-bill length. Finally, GWAS analyses suggested many loci of small effect contributing to trait variation for all three traits, although one locus (an SNP within an intron of the transcription factor HEY2) was tentatively associated with tarsus length. Our findings suggest a polygenic nature for the morphological traits, with many small effect size loci contributing to the majority of the variation, similar to results from many other wild populations. However, the small effective population size, polygenic architecture and already low heritabilities suggest that both the total response and rate of response to selection are likely to be limited in hihi.


Assuntos
Evolução Biológica , Passeriformes , Animais , Cromossomos , Estudo de Associação Genômica Ampla , Genômica , Modelos Genéticos , Herança Multifatorial , Nova Zelândia , Linhagem , Fenótipo
15.
PLoS Biol ; 18(8): e3000838, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32804933

RESUMO

In humans, most germline mutations are inherited from the father. This observation has been widely interpreted as reflecting the replication errors that accrue during spermatogenesis. If so, the male bias in mutation should be substantially lower in a closely related species with similar rates of spermatogonial stem cell divisions but a shorter mean age of reproduction. To test this hypothesis, we resequenced two 3-4 generation nuclear families (totaling 29 individuals) of olive baboons (Papio anubis), who reproduce at approximately 10 years of age on average, and analyzed the data in parallel with three 3-generation human pedigrees (26 individuals). We estimated a mutation rate per generation in baboons of 0.57×10-8 per base pair, approximately half that of humans. Strikingly, however, the degree of male bias in germline mutations is approximately 4:1, similar to that of humans-indeed, a similar male bias is seen across mammals that reproduce months, years, or decades after birth. These results mirror the finding in humans that the male mutation bias is stable with parental ages and cast further doubt on the assumption that germline mutations track cell divisions. Our mutation rate estimates for baboons raise a further puzzle, suggesting a divergence time between apes and Old World monkeys of 65 million years, too old to be consistent with the fossil record; reconciling them now requires not only a slowdown of the mutation rate per generation in humans but also in baboons.


Assuntos
Mutação em Linhagem Germinativa , Hominidae/genética , Taxa de Mutação , Papio/genética , Reprodução/genética , Espermatozoides/metabolismo , Fatores Etários , Animais , Evolução Biológica , Divisão Celular , Feminino , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Masculino , Modelos Genéticos , Linhagem , Fatores Sexuais , Especificidade da Espécie , Espermatogênese/genética , Espermatozoides/citologia
16.
Artigo em Chinês | MEDLINE | ID: mdl-32842192

RESUMO

To study the clinical features and causes of congenital Usher hearing loss in one child. Clinical examination, audiological tests, visual acuity examination were conducted in the proband and its family members, and second-generation sequencing technology for deafness gene detection was employed. The proband exhibited profound sensorineural deafness(hearing threshold>90 dB nHL). There was no visual loss after follow-up. Other family members had no history of hearing loss. The gene test indicated that the proband had a frameshift mutation for the thymine(T) deletion at the 1527 site of the Usher1C gene. The mutation was a homozygous mutation, and was from the father and the mother, respectively, which caused the truncation of the encoded protein. Normal function, Usher syndrome or non-syndromic deafness DFNB18 can occur. This is the first case in China demonstrating congenital deafness due to homozygous mutation of Usher1C gene c. 1527delT. This study enriches the gene spectrum of deafness in China.


Assuntos
Surdez/genética , Perda Auditiva Neurossensorial/genética , Síndromes de Usher , Criança , China , Testes Genéticos , Humanos , Mutação , Linhagem
17.
PLoS One ; 15(8): e0237814, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32804975

RESUMO

Schaaf-Yang syndrome (SYS) is a neurodevelopmental disorder caused by truncating variants in the paternal allele of MAGEL2, located in the Prader-Willi critical region, 15q11-q13. Although the phenotypes of SYS overlap those of Prader-Willi syndrome (PWS), including neonatal hypotonia, feeding problems, and developmental delay/intellectual disability, SYS patients show autism spectrum disorder and joint contractures, which are atypical phenotypes for PWS. Therefore, we hypothesized that the truncated Magel2 protein could potentially produce gain-of-function toxic effects. To test the hypothesis, we generated two engineered mouse models; one, an overexpression model that expressed the N-terminal region of Magel2 that was FLAG tagged with a strong ubiquitous promoter, and another, a genome-edited model that carried a truncating variant in Magel2 generated using the CRISPR/Cas9 system. In the overexpression model, all transgenic mice died in the fetal or neonatal period indicating embryonic or neonatal lethality of the transgene. Therefore, overexpression of the truncated Magel2 could show toxic effects. In the genome-edited model, we generated a mouse model carrying a frameshift variant (c.1690_1924del; p(Glu564Serfs*130)) in Magel2. Model mice carrying the frameshift variant in the paternal or maternal allele of Magel2 were termed Magel2P:fs and Magel2M:fs, respectively. The imprinted expression and spatial distribution of truncating Magel2 transcripts in the brain were maintained. Although neonatal Magel2P:fs mice were lighter than wildtype littermates, Magel2P:fs males and females weighed the same as their wildtype littermates by eight and four weeks of age, respectively. Collectively, the overexpression mouse model may recapitulate fetal or neonatal death, which are the severest phenotypes for SYS. In contrast, the genome-edited mouse model maintains genomic imprinting and distribution of truncated Magel2 transcripts in the brain, but only partially recapitulates SYS phenotypes. Therefore, our results imply that simple gain-of-function toxic effects may not explain the patho-mechanism of SYS, but rather suggest a range of effects due to Magel2 variants as in human SYS patients.


Assuntos
Antígenos de Neoplasias/genética , Mutação/genética , Proteínas/genética , Animais , Antígenos de Neoplasias/química , Antígenos de Neoplasias/metabolismo , Peso Corporal , Encéfalo/metabolismo , Modelos Animais de Doenças , Feminino , Edição de Genes , Regulação da Expressão Gênica , Células HEK293 , Humanos , Masculino , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Linhagem , Fenótipo , Proteínas/química , Proteínas/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo
18.
DNA Cell Biol ; 39(10): 1760-1766, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32808810

RESUMO

Congenital cataract refers to a lens opacity caused by multiple etiological factors, including genetic mutation, abnormal metabolism of the lens, and infection. Currently, there are >100 known disease-causing genes as well as 60 known mutations in the Cx46 gene (Gap junction alpha-3, GJA3) associated with congenital cataracts. Dysfunction of gap junctions impairs homeostasis in lens cells, thereby inducing cataract pathogenesis. This study aims to identify the disease-causing mutation in a family with congenital cataract, and to further explore the possible pathogenic mechanism resulting from this mutation. We identified that a recurrent heterozygous missense mutation c.T148C (p.S50P) in GJA3 was the pathogenic mutation in this family. Previously, this mutation was found in a British family causing bilateral congenital cataract. We further demonstrated that CX46 wild type (WT) was coupled through functional gap junctions in HeLa cells, while mutant Cx46 S50P lost this ability. Moreover, the half-life of Cx46 S50P was longer than that of Cx46 WT, Cx46 S50P protein was also localized to the endoplasmic reticulum and induced more reactive oxygen species compared to Cx46 WT, which may lead to dysregulation of Cx46-formed gap junction. Collectively, our study defines the genetics basis of a congenital cataract family as well as the cellular mechanisms of mutant Cx46 S50P, and provides useful information for further studies of the pathogenesis and therapeutic strategy for treating congenital cataract.


Assuntos
Catarata/genética , Conexinas/genética , Mutação , Adulto , Catarata/metabolismo , Catarata/patologia , Criança , Conexinas/metabolismo , Retículo Endoplasmático/metabolismo , Feminino , Junções Comunicantes/metabolismo , Junções Comunicantes/patologia , Células HeLa , Humanos , Masculino , Linhagem , Ligação Proteica , Espécies Reativas de Oxigênio/metabolismo
19.
PLoS One ; 15(8): e0237999, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32822427

RESUMO

Hyper-IgD syndrome (HIDS, OMIM #260920) is a rare autosomal recessive autoinflammatory disorder caused by pathogenic variants in the mevalonate kinase (MVK) gene. HIDS has an incidence of 1:50,000 to 1:5,000, and is thought to be prevalent mainly in northern Europe. Here, we report a case series of HIDS from India, which includes ten patients from six families who presented with a wide spectrum of clinical features such as recurrent fever, oral ulcers, rash, arthritis, recurrent diarrhea, hepatosplenomegaly, and high immunoglobulin levels. Using whole exome sequencing (WES) and/or Sanger capillary sequencing, we identified five distinct genetic variants in the MVK gene from nine patients belonging to six families. The variants were classified as pathogenic or likely pathogenic as per the American College of Medical Genetics and Genomics and the Association for Molecular Pathology (ACMG-AMP) guidelines for annotation of sequence variants. Over 70% of patients in the present study had two recurrent mutations in MVK gene i.e. a nonsynonymous variant p.V377I, popularly known as the 'Dutch mutation', along with a splicing variant c.226+2delT in a compound heterozygous form. Identity by descent analysis in two patients with the recurrent variants identified a 6.7 MB long haplotype suggesting a founder effect in the South Indian population. Our analysis suggests that a limited number of variants account for the majority of the patients with HIDS in South India. This has implications in clinical diagnosis, as well as in the development of cost-effective approaches for genetic diagnosis and screening. To our best knowledge, this is the first and most comprehensive case series of clinically and genetically characterized patients with HIDS from India.


Assuntos
Grupo com Ancestrais do Continente Asiático/genética , Deficiência de Mevalonato Quinase/patologia , Fosfotransferases (Aceptor do Grupo Álcool)/genética , Adolescente , Pré-Escolar , Feminino , Deleção de Genes , Estudos de Associação Genética , Haplótipos , Heterozigoto , Humanos , Índia , Lactente , Masculino , Deficiência de Mevalonato Quinase/genética , Linhagem , Fosfotransferases (Aceptor do Grupo Álcool)/química , Polimorfismo de Nucleotídeo Único , Estrutura Terciária de Proteína , Sequenciamento Completo do Exoma
20.
PLoS One ; 15(8): e0238079, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32845916

RESUMO

BACKGROUND: Sitosterolemia is an inherited lipid disorder which presents with elevated serum sitosterol and can result in an increased risk of premature cardiovascular disease. However, sitosterol cannot be accurately measured by routine diagnostic assays, meaning that sitosterolemia diagnosis can often be difficult, especially with many clinical features overlapping with familial hypercholesterolemia. With such complications resulting in increasing reports of misdiagnosis, the prevalence of sitosterolemia is predicted to be much higher than previously reported. METHODS: Gas chromatography-mass spectrometry was utilized to measure sitosterol levels of normocholesterolemic and hypercholesterolemic children. Subsequently, an epidemiologically determined cutoff level of sitosterol was calculated and applied to estimate the prevalence of children with increased sitosterol and identify potential sitosterolemia patients. Massively parallel sequencing was used to confirm the diagnosis in suspected patients. RESULTS: Samples from 109 normocholesterolemic and 220 hypercholesterolemic were tested for phytosterols. Sitosterol and campesterol levels were significantly increased in hypercholesterolemic children (mean 22.0±45.9 µmol/L for sitosterol and 26.0±32.8 µmol/L for campesterol) compared to normocholesterolemic children (mean 12.1±4.9 µmol/L for sistosterol and 14.8±6.7 µmol/L for campesterol). Via application of a cutoff of 35.9 µmol/L, the prevalence rates for increased and overtly increased sitosterol in hypercholesterolemic children were 6.4% and 1.4% respectively. Furthermore, 3 suspected sitosterolemia patients were identified, with 2 patients receiving molecular confirmation for sitosterolemia diagnosis. CONCLUSIONS: Our findings reaffirm that the prevalence of sitosterolemia is probably much higher than previously reported, which also indicates the significant risk of misdiagnosis of sitosterolemia with familial hypercholesterolemia. Special lipid testing including sitosterol, especially in children with uncontrolled hypercholesterolemia, is recommended in children in order to identify potential sitosterolemia patients that would otherwise be neglected.


Assuntos
Hipercolesterolemia/diagnóstico , Sitosteroides/análise , Membro 5 da Subfamília G de Transportadores de Cassetes de Ligação de ATP/genética , Membro 8 da Subfamília G de Transportadores de Cassetes de Ligação de ATP/genética , Adolescente , Criança , Pré-Escolar , Colesterol/análogos & derivados , Colesterol/análise , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Hipercolesterolemia/epidemiologia , Hipercolesterolemia/genética , Lactente , Enteropatias/diagnóstico , Enteropatias/epidemiologia , Enteropatias/genética , Erros Inatos do Metabolismo Lipídico/diagnóstico , Erros Inatos do Metabolismo Lipídico/epidemiologia , Erros Inatos do Metabolismo Lipídico/genética , Lipoproteínas/genética , Masculino , Linhagem , Fitosteróis/efeitos adversos , Fitosteróis/análise , Fitosteróis/genética , Prevalência
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