The identification of a novel splicing mutation in the DMD gene of a Chinese family.
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ABSTRACT:
SUBMITTER: Liu W
PROVIDER: S-EPMC8659554 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BackgroundPatients with Duchenne muscular dystrophy (DMD) usually have severe and fatal symptoms. At present, there is no effective treatment for DMD, thus it is very important to avoid the birth of children with DMD by effective prenatal diagnosis. We identified a de novo DMD gene mutation in a Chinese family, and make a prenatal diagnosis.MethodsFirst, multiplex ligation-dependent probe amplification (MLPA) was applied to analyze DMD gene exon deletion/duplication in all family members. The coding sequences of 79 exons in DMD gene were analyzed by Sanger sequencing in the patient; and then according to DMD gene exon mutation in the patient, DMD gene sequencing was performed in the family members. On the basis of results above, the pathogenic mutation in DMD gene was identified.ResultsMLPA showed no DMD gene exon deletion/duplication in all family members. Sanger sequencing revealed c.2767_2767delT [p.Ser923LeufsX26] mutation in DMD gene of the patient. Heterozygous deletion mutation (T/-) at this locus was observed in the pregnant woman and her mother and younger sister. The analyses of amniotic fluid samples indicated negative Y chromosome sex-determining gene, no DMD gene exon deletion/duplication, no mutations at c.2767 locus, and the inherited maternal X chromosome different from that of the patient.ConclusionThe pathogenic mutation in DMD gene, c.2767_2767delT [p.Ser923LeufsX26], identified in this family is a de novo mutation. On the basis of specific conditions, it is necessary to select suitable methods to make prenatal diagnosis more effective, accurate, and economic.
| S-EPMC5815683 | biostudies-literature
Project description:This study was aimed to detect a new mutation responsible for X-linked dilated cardiomyopathy with hyper-CKemia.We studied a proband who presented with cardiac symptoms with hyper-CKemia, but no clinical skeletal involvement in physical examination, laboratory tests, electromyography, echocardiography, and magnetic resonance imaging (MRI) of cardiac muscles. Muscle biopsy for histopathology and immunohistochemistry for accessing sarcolemma changes. The next-generation sequencing and bioinformatics analysis were performed on the patient and Sanger sequencing was confirmed on the other 6 unaffected families.The clinic investigations illustrated a dilated cardiomyopathy. Histopathology and immunohistochemistry showed dystrophic changes and an obvious reduction of dystrophin-N and ?-sarcoglycan, respectively. One hemizygous splicing pathogenic mutation c.31?+?1G?>?C of exon 1 in the DMD gene (chrX33229398, NM_00 4006) was finally identified in the patient and his nephew, but it was carried in his mother and sister.A novel small mutation was identified at the first exon-intron boundary splicing site by next-generation sequencing and bioinformatics analysis.
| S-EPMC6024070 | biostudies-literature
Project description:PurposeTo identify the mutation in the fibrillin-1 gene (FBN1) in a Chinese family with Marfan syndrome (MFS).MethodsPatients and family members were given complete physical, ophthalmic, and cardiovascular examinations. Genomic DNA was extracted from leukocytes of venous blood of six individuals in the family and 170 healthy Chinese individuals. All of the 65 coding exons and their flanking intronic boundaries of FBN1 were amplified in the proband by polymerase chain reaction and followed by direct sequencing. The mutation identified in the proband was screened in the other family members and the 170 healthy Chinese individuals by direct sequencing. Protein conservation analysis was performed in six species using an online ClustalW tool. Protein structure was modeled based on the Protein data bank and mutated in DeepView v4.0.1 to predict the functional consequences of the mutation.ResultsA novel heterozygous c.3703T>C change in exon 29 of FBN1 was detected in the proband, which resulted in the substitution of serine by proline at codon 1235 (p.S1235P). This mutation was also present in two family members but absent in the other, unaffected family members and the 170 healthy Chinese individuals. The mutant residue located in the calcium binding epidermal growth factor-like#15 domain is highly conserved among mammalian species and could probably induce conformation change of the domain.ConclusionsWe indentified a novel p.S1235P mutation in FBN1, which is the causative mutation for MFS in this family. Our result expands the mutation spectrum of FBN1 and contributes to the study of the molecular pathogenesis of Marfan syndrome.
| S-EPMC3185025 | biostudies-literature
Project description:PURPOSE: To identify a potential pathogenic mutation in a four-generation Chinese family with X-linked congenital nystagmus (XLCN). METHODS: Routine clinical examination and ophthalmic evaluation were performed on normal controls, two patients and two healthy members of the family. Genomic DNA was prepared from the peripheral blood of members of the family and from 50 normal controls. All coding exons and the intronic boundaries of the four-point-one (4.1), ezrin, radixin, moesin (FERM) domain-containing 7 (FRMD7) gene were amplified using polymerase chain reaction (PCR) followed by direct sequencing. RESULTS: A previously unreported splicing mutation, c.163-1 G?T transversion (c.163-1 G>T), was detected preceding exon3 of FRMD7 in the patients but not in the unaffected family members and 50 unrelated healthy individuals. CONCLUSIONS: We identified a novel mutation (c.163-1 G?T) of FRMD7 in this Chinese family with XLCN. Our finding is the first report related to c.163-1 G?T mutation in FRMD7. The result expands the mutation spectrum of FRMD7 in association with congenital nystagmus.
| S-EPMC3261083 | biostudies-literature
Project description:BACKGROUND:Desminopathy, a hereditary myofibrillar myopathy, mainly results from the desmin gene (DES) mutations. Desminopathy involves various phenotypes, mainly including different cardiomyopathies, skeletal myopathy, and arrhythmia. Combined with genotype, it helps us precisely diagnose and treat for desminopathy. METHODS:Sanger sequencing was used to characterize DES variation, and then a minigene assay was used to verify the effect of splice-site mutation on pre-mRNA splicing. Phenotypes were analyzed based on clinical characteristics associated with desminopathy. RESULTS:A splicing mutation (c.735+1G>T) in DES was detected in the proband. A minigene assay revealed skipping of the whole exon 3 and transcription of abnormal pre-mRNA lacking 32 codons. Another affected family member who carried the identical mutation, was identified with a novel phenotype of desminopathy, non-compaction of ventricular myocardium. There were 2 different phenotypes varied in cardiomyopathy and skeletal myopathy among the 2 patients, but no significant correlation between genotype and phenotype was identified. CONCLUSIONS:We reported a novel phenotype with a splicing mutation in DES, enlarging the spectrum of phenotype in desminopathy. Molecular studies of desminopathy should promote our understanding of its pathogenesis and provide a precise molecular diagnosis of this disorder, facilitating clinical prevention and treatment at an early stage.
| S-EPMC6365268 | biostudies-literature
Project description:Pseudoexon (PE) inclusion has been implicated in various dystrophinopathies; however, its splicing characteristics have not been fully investigated. This study aims to analyze the splicing characteristics of dystrophin PEs and compare them with those of dystrophin canonical exons (CEs). Forty-two reported dystrophin PEs were divided into a splice site (ss) group and a splicing regulatory element (SRE) group. Five dystrophin PEs with characteristics of poison exons were identified and categorized as the possible poison exon group. The comparative analysis of each essential splicing signal among different groups of dystrophin PEs and dystrophin CEs revealed that the possible poison exon group had a stronger 3' ss compared to any other group. As for auxiliary SREs, different groups of dystrophin PEs were found to have a smaller density of diverse types of exonic splicing enhancers and a higher density of several types of exonic splicing silencers compared to dystrophin CEs. In addition, the possible poison exon group had a smaller density of 3' ss intronic splicing silencers compared to dystrophin CEs. To our knowledge, our findings indicate for the first time that poison exons might exist in DMD (the dystrophin gene) and present with different splicing characteristics than other dystrophin PEs and CEs.
| S-EPMC7650627 | biostudies-literature
Project description:PurposeTo describe the clinical and genetic findings in one Chinese family with juvenile-onset open angle glaucoma (JOAG).MethodsOne family was examined clinically and a follow-up took place 5 years later. After informed consent was obtained, genomic DNA was extracted from the venous blood of all participants. Linkage analysis was performed with three microsatellite markers around the MYOC gene (D1S196, D1S2815, and D1S218) in the family. Mutation screening of all coding exons of MYOC was performed by direct sequencing of PCR-amplified DNA fragments and restriction fragment length polymorphism (RFLP) analysis. Bioinformatics analysis by the Garnier-Osguthorpe-Robson (GOR) method predicted the effects of variants detected on secondary structures of the MYOC protein.ResultsClinical examination and pedigree analysis revealed a three- generation family with seven members diagnosed with JOAG, three with ocular hypertension, and five normal individuals. Through genotyping, the pedigree showed a linkage to the MYOC on chromosome 1q24-25. Mutation screening of MYOC in this family revealed an A-->T transition at position 1348 (p. N450Y) of the cDNA sequence. This missense mutation co-segregated with the disease phenotype of the family, but was not found in 100 normal controls. Secondary structure prediction of the p.N450Y by the GOR method revealed the replacement of a coil with a beta sheet at the amino acid 447.ConclusionsEarly onset JOAG, with incomplete penetrance, is consistent with a novel mutation in MYOC. The finding provides pre-symptomatic molecular diagnosis for the members of this family and is useful for further genetic consultation.
| S-EPMC2927375 | biostudies-literature
Project description:Hypertrophic cardiomyopathy (HCM) is a type of primary cardiomyopathy with genetic etiology, and it carries a high risk of diastolic dysfunction, heart failure, and malignant arrhythmias. We reported the first familial HCM in China, caused by a novel FLNC splicing mutation. We performed duo exome sequencing (ES) to examine the genome of the proband and his mother. For 10 days, a 15-year-old boy was presented to our hospital due to non-exercise-associated chest tightness and asthma. He was diagnosed with HCM [end-diastolic interventricular septal thickness was about 18 mm by transthoracic echocardiography (TTE)]. His mother and sister performed TTE to screen familial cardiomyopathy, which revealed hypertrophic cardiomyopathy only in the proband's mother. In ES of the mother-son duo, we identified a novel heterozygous mutation of the FLNC gene (chr7:128492808, NM_001127487, c.5905+2T>C, rs1808874360) as the candidate cause of autosomal dominant HCM. Sanger sequencing confirmed this novel mutation in the proband and his mother but absent in the proband's sister. The potential impact of the novel mutation was predicted by MutationTaster, dbscSNV_ADA_SCORE, dbscSNV_RF_SCORE, CADD_phred, PhyloP20way_mammalian, PhyloP100way_vertebrate, SiPhy_29way_logOdds, and GERP++_RS software. After the administration of furosemide, spironolactone, and metoprolol, the proband's heart function was improved, and symptoms were alleviated. We presented the first familial HCM caused by a novel FLNC splicing mutation via exome sequencing in China. Therefore, it is necessary that familial screening for patients with HCM should be performed for the early detection of HCM intervention in malignant cardiac events in advance and block genes.
| S-EPMC9251305 | biostudies-literature
Project description:Spondyloepiphyseal dysplasia congenita (SEDC) is an autosomal dominant chondrodysplasia characterized by disproportionate short-trunk dwarfism, skeletal and vertebral deformities. Exome sequencing and Sanger sequencing were performed in a Chinese Han family with typical SEDC, and a novel mutation, c.620G>A (p.Gly207Glu), in the collagen type II alpha-1 gene (COL2A1) was identified. The mutation may impair protein stability, and lead to dysfunction of type II collagen. Family-based study suggested that the mutation is a de novo mutation. Our study extends the mutation spectrum of SEDC and confirms genotype-phenotype relationship between mutations at glycine in the triple helix of the alpha-1(II) chains of the COL2A1 and clinical findings of SEDC, which may be helpful in the genetic counseling of patients with SEDC.
| S-EPMC4452087 | biostudies-literature
Project description:OBJECTIVE: Axenfeld-Rieger syndrome (ARS) is phenotypically and genetically heterogeneous. In this study, we identified the underlying genetic defect in a Chinese family with ARS. METHODS: A detailed family history and clinical data were recorded. The ocular phenotype was documented using slit-lamp photography and systemic anomalies were also documented where available. The genomic DNA was extracted from peripheral blood leukocytes. All coding exons and intron-exon junctions of paired-like homeodomain transcription factor 2 (PITX2) gene and the forkhead box C1 (FOXC1) gene were amplified by polymerase chain reaction (PCR) and screened for mutation by direct DNA sequencing. Variations detected in exon 5 of PITX2 were further evaluated with cloning sequencing. The exon 5 of PITX2 was also sequenced in 100 healthy controls, unrelated to the family, for comparison. Structural models of the wild type and mutant homeodomain of PITX2 were investigated by SWISS-MODEL. RESULTS: Affected individuals exhibited variable ocular phenotypes, whereas the systemic anomalies were similar. After direct sequencing and cloning sequencing, a heterozygous deletion/insertion mutation c.198_201delinsTTTCT (p.M66Ifs*133) was revealed in exon 5 of PITX2. This mutation co-segregated with all affected individuals in the family and was not found either in unaffected family members or in 100 unrelated controls. CONCLUSIONS: We detected a novel frameshift mutation p.M66Ifs*133 in PITX2 in a Chinese family with ARS. Although PITX2 mutations and polymorphisms have been reported from various ethnic groups, we report for the first time the identification of a novel deletion/insertion mutation that causes frameshift mutation in the homeodomain of PITX2 protein.
| S-EPMC3891117 | biostudies-literature