Hearing Loss, Sensorineural ; genetics ; Humans

Hearing Loss ; genetics ; Humans ; Mitochondria ; genetics ; Mutation

Objective:To analyze the phenotype and genotype characteristics of autosomal recessive hearing loss caused by MYO15A gene variants, and to provide genetic diagnosis and genetic counseling for patients and their families. Methods:Identification of MYO15A gene variants by next generation sequencing in two sporadic cases of hearing loss at Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine. The sequence variants were verified by Sanger sequencing.The pathogenicity of these variants was determined according to the American College of Medical Genetics and Genomics（ACMG） variant classification guidelines, in conjuction with clinical data. Results:The probands of the two families have bilateral,severe or complete hearing loss.Four variants of MYO15A were identified, including one pathogenic variant that has been reported, two likely pathogenic variants,and one splicing variant of uncertain significance. Patient I carries c. 3524dupA（p. Ser1176Valfs*14）, a reported pathogenic variant, and a splicing variant c. 10082+3G>A of uncertain significance according to the ACMG guidelines. Patient I was treated with bilateral hearing aids with satisfactory effect, demonstrated average hearing thresholds of 37.5 dB in the right ear and 33.75 dB in the left ear. Patient Ⅱ carries c. 7441_7442del（p. Leu2481Glufs*86） and c. 10250_10252del（p. Ser3417del）,a pair of as likely pathogenic variants according to the ACMG guidelines. Patient Ⅱ, who underwent right cochlear implantation eight years ago, achieved scores of 9 on the Categorical Auditory Performance-Ⅱ（CAP-Ⅱ） and 5 on the Speech Intelligibility Rating（SIR）. Conclusion:This study's discovery of the rare c. 7441_7442del variant and the splicing variant c. 10082+3G>A in the MYO15A gene is closely associated with autosomal recessive hearing loss, expanding the MYO15A variant spectrum. Additionally, the pathogenicity assessment of the splicing variant facilitates classification of splicing variations.
Humans ; Pedigree ; China ; Deafness/genetics* ; Hearing Loss/genetics* ; Phenotype ; Hearing Loss, Sensorineural/genetics* ; Mutation ; Myosins/genetics*

Genetic counseling for hearing loss today originated from decoding the genetic code of hereditary hearing loss, which serves as an effective strategy for preventing hearing loss and constitutes a crucial component of the diagnostic and therapeutic framework. This paper described the main principles and contents of genetic counseling for hearing loss, the key points of counseling across various genetic models and its application in tertiary prevention strategies targeting hearing impairment. The prospects of an AI-assisted genetic counseling decision system and the envisions of genetic counseling in preventing hereditary hearing loss were introduced. Genetic counseling for hearing loss today embodies the hallmark of a new era, which is inseparable from the advancements in science and technology, and will undoubtedly contribute to precise gene intervention!
Humans ; Genetic Counseling ; Deafness/genetics* ; Hearing Loss/diagnosis* ; Hearing Loss, Sensorineural/genetics*

BACKGROUNDMutations in GJB2 gene are a major cause of autosomal recessive congenital hearing loss and the cause in some rare cases of the autosomal dominant form. The purpose of this study was to investigate the frequency and the features of GJB2 mutations in the Chinese patients with congenital sensorineural deafness.

METHODSUsing PCR amplifying the entire coding region of GJB2 gene and direct DNA sequencing to analyze mutations in this gene among unrelated 69 cases with autosomal recessive congenital nonsyndromic deafness and 27 cases of dominant congenital deafness and 35 sporadic cases. We also detected mutations in GJB2 in 100 control subjects with normal hearing.

RESULTS17.4% (12/69) of the probands in the autosomal recessive, 7.4% (2/27) of dominant families and 5.7% (2/35) of the sporadic congenital deafness patients had deafness-causing mutations in GJB2, respectively. Nine types of the mutations in GJB2 were detected in the recessive and sporadic group. They consisted of five types of polymorphism, and four types of deafness-causing mutation with homozygous 35delG in 1 sporadic (1/35), and 235delC frameshift mutation in 1 sporadic (homozygotes) and 10 recessive patients (2 heterozygotes and 8 homozygotes), and homozygous 442G-->A missense mutation and homozygous 465T-->A nonsense mutation in 1 different recessive proband, respectively. The 465T-->A that related to recessive deafness was a novel mutation found by this study. The homozygous (10/69, 14.5%) and the heterozygous (2/69, 2.9%) GJB2 mutation in the recessive patients (12/69, 17.4%) and the homozygotes in the sporadic patient (2/35, 5.7%) all had congenital severe to profound sensorineural hearing loss. 511G-->A missense mutation and 299-300delAT frameshift mutation were found in two autosomal dominant congenital deafness families (2/27, 7.4%). The total mutation frequency of GJB2 was 12.2% (16/131) in the Chinese patients with congenital sensorineural deafness and 235delC was the most common deafness-causing mutation. Six types of mutation-5 types of polymorphism and 1 type of heterozygous deletion (235delC) mutation were found in the 100 control subjects. The carry rate of the most frequent type of mutation 235delC was 0.5% in the controls (1/200 alleles). 109G-->A was the most frequent (15/100, 15%) and 79G-->A was the second common (8/100, 8%) polymorphism in this population.

CONCLUSIONSThe general mutation rate of GJB2 is 12.2% (16/131) and the 235delC is the most common type of deafness-causing mutation in Chinese patients with congenital hearing loss. 465T-->A nonsense mutation that is associated to autosomal recessive deafness is a novel mutation found by this screening. 511G-->A and 299-300delAT mutations contribute to autosomal dominant hearing loss. The study further supports the view that the common types of mutation in GJB2 according to different ethnic background and that the mutation prevalence in the East Asian deafness population is lower than that in the white population.

Cadherins ; genetics ; Hearing Loss, Sensorineural ; genetics ; pathology ; Humans

Humans ; Deafness/genetics* ; Hearing Loss, Sensorineural/genetics* ; Y Chromosome

OBJECTIVETo investigate the clinical and genetic characteristics of a large family with late-onset, progressive autosomal dominant non-syndromic hearing loss.

METHODSCollections of detail history hereditary features, physical and audiological examination were performed. After mutation screening of GJB2, SLC26A4, MTRNR1 (12SrRNA) genes by Sanger sequencing, the proband was investigated by targeted next-generation sequencing of 79 deafness genes.

RESULTSThis family included seven generations and 73 members. Eleven persons with hearing loss and 11 normal-hearing persons participated in this study. All affected members but one exhibited late-onset, progressive non-syndromic sensorineural hearing loss; the ages of onset were between 9 and 30 years. Mutation screening by sanger-sequencing and targeted next-generation sequencing excluded the possibility of pathogenic mutations within known deafness gene.

CONCLUSIONSA Chinese family with late-onset progressive non-syndromic sensorineural hearing loss was investigated clinically and genetically. By candidate gene approach and targeted next-generation sequencing, this family was preliminary proved to be caused by unknown deafness gene.

Diagnosis of pre-lingual hearing loss (HL) is difficult owing to the high number of genes responsible. The most frequent cause of HL is DFNB1 due to mutations in the GJB2 gene. It represents up to 40% of HL cases in some populations. In Iran, it has previously been shown that DFNB1 accounts for 16-18% of cases but varies among different ethnic groups. Here, we reviewed results from our three previous publications and data from other published mutation reports to provide a comprehensive collection of data for GJB2 mutations and HL in northern Iran. In total, 903 unrelated families from six different provinces, viz., Gilan, Mazandaran, Golestan, Ghazvin, Semnan, and Tehran, were included and analyzed for the type and prevalence of GJB2 mutations. A total of 23 different genetic variants were detected from which 18 GJB2 mutations were identified. GJB2 mutations were 20.7% in the studied northern provinces, which was significantly higher than that reported in southern populations of Iran. Moreover, a gradient in the frequency of GJB2 mutations from north to south Iran was observed. c.35delG was the most common mutation, accounting for 58.4% of the cases studied. This study suggests that c.35delG mutation in GJB2 is the most important cause of HL in northern Iran.
Diagnosis ; Ethnic Groups ; Genetic Counseling ; Genetics ; Hearing Loss ; Hearing ; Humans ; Iran ; Prevalence

Objective:To elucidate the correlation between the GJB2 gene and auditory neuropathy, aiming to provide valuable insights for genetic counseling of affected individuals and their families. Methods:The general information, audiological data（including pure tone audiometry, distorted otoacoustic emission, auditory brainstem response, electrocochlography）, imaging data and genetic test data of 117 auditory neuropathy patients, and the patients with GJB2 gene mutation were screened out for the correlation analysis of auditory neuropathy. Results:Total of 16 patients were found to have GJB2 gene mutations, all of which were pathogenic or likely pathogenic.was Among them, one patient had compound heterozygous variants GJB2[c. 427C>T][c. 358_360del], exhibiting total deafness. One was GJB2[c. 299_300delAT][c. 35_36insG]compound heterozygous variants, the audiological findings were severe hearing loss.The remaining 14 patients with GJB2 gene variants exhibited typical auditory neuropathy. Conclusion:In this study, the relationship between GJB2 gene and auditory neuropathy was preliminarily analyzed,and explained the possible pathogenic mechanism of GJB2 gene variants that may be related to auditory neuropathy.
Humans ; Connexins/genetics* ; Connexin 26/genetics* ; Hearing Loss, Central/genetics* ; Deafness/genetics* ; Mutation