Hearing Loss, Sensorineural ; genetics ; Humans

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*

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

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*

Next-generation sequencing (NGS) technologies have improved as well as the costs have gradually decreased in the detections of genetic diseases. This article describes the principle, platform, and data analysis of NGS and the application of NGS technologies to the molecular diagnosis of hereditary hearing loss (HL). The use of NGS technologies makes the discovery of HL genes more feasible than ever. And the data obtained by NGS used in genetic counseling for clinical practice may assist in defining genetic profiles of HL individuals and expedite the pace of personalized medical care.
Hearing Loss, Sensorineural ; diagnosis ; genetics ; High-Throughput Nucleotide Sequencing ; Humans

OBJECTIVE: Mutations in the GJB2 are the most common cause of nonsyndromic autosomal recessive sensorineural hearing loss. A few mutations in GJB2 have also been reported to cause dominant nonsyndromic or syndromic hearing loss. This study analysised the GJB2 dominant mutation in Chinese deafness. METHOD: 1641 patients as GJB2-related hearing loss were enrolled, summarized the type of dominant mutaion, analyzed the hearing level and other systerm lesion. RESULT: Nine probands with severe-profound hearing loss were diagnosed as GJB2 domiant mutation (R75W,G130V, R143Q,p. R184Q). And one patient with R75W mutation was diagosed as hearing loss and palmoplantar keratoderma. CONCLUSION GJB2 dominant mutation can cause severe-to-profound bilateral sensorineural hearing impairment and not common with syndromic hearing loss in Chinese deafness.
Asian Continental Ancestry Group ; Connexin 26 ; Connexins ; genetics ; Deafness ; genetics ; Hearing Loss ; Hearing Loss, Sensorineural ; Humans ; Keratoderma, Palmoplantar ; Mutation ; Phenotype

Objective:To dentify the genetic and audiological characteristics of families affected by late-onset hearing loss due to GSDMEgene mutations, aiming to explore clinical characteristics and pathogenic mechanisms for providing genetic counseling and intervention guidance. Methods:Six families with late-onset hearing loss from the Chinese Deafness Genome Project were included. Audiological tests, including pure-tone audiometry, acoustic immittance, speech recognition scores, auditory brainstem response, and distortion product otoacoustic emission, were applied to evaluate the hearing levels of patients. Combining with medical history and physical examination to analyze the phenotypic differences between the probands and their family members. Next-generation sequencing was used to identify pathogenic genes in probands, and validations were performed on their relatives by Sanger sequencing. Pathogenicity analysis was performed according to the American College of Medical Genetics and Genomics Guidelines. Meanwhile, the pathogenic mechanisms of GSDME-related hearing loss were explored combining with domestic and international research progress. Results:Among the six families with late-onset hearing loss, a total of 30 individuals performed hearing loss. The onset of hearing loss in these families ranged from 10 to 50 years（mean age: 27.88±9.74 years）. In the study, four splicing mutations of the GSDME were identified, including two novel variants: c. 991－7C>G and c. 1183+1G>T. Significantly, the c. 991－7C>G was a de novo variant. The others were previously reported variants: c. 991-1G>C and c. 991-15_991-13del, the latter was identified in three families. Genotype-phenotype correlation analysis revealed that probands with the c. 991－7C>G and c. 1183+1G>T performed a predominantly high-frequency hearing loss. The three families carrying the same mutation exhibited varying degrees of hearing loss, with an annual rate of hearing deterioration exceeding 0.94 dB HL/year. Furthermore, follow-up of interventions showed that four of six probands received intervention（66.67%）, but the results of intervention varied. Conclusion:The study analyzed six families with late-onset non-syndromic hearing loss linked to GSDME mutations, identifying four splicing variants. Notably, c. 991－7C>G is the first reported de novo variant of GSDME globally. Audiological analysis revealed that the age of onset generally exceeded 10 years,with variable effectiveness of interventions.
Humans ; Adolescent ; Young Adult ; Adult ; Child ; Hearing Loss, Sensorineural/diagnosis* ; Deafness/genetics* ; Mutation ; Hearing Loss/genetics* ; Pedigree

OBJECTIVE: To explore the genetic basis for a Chinese pedigree affected with non-syndromic hearing loss (NSHL). METHODS: Commercialized gene chip was applied to detect common mutations associated with congenital deafness. Whole exome sequencing was carried out for patients for whom gene chip yielded a negative result. Candidate variants were verified by Sanger sequencing. RESULTS: Two patients from the pedigree were discovered to carry compound heterozygous variants of the TRIOBP gene, namely c.3299C>A and c.5185-2A>G. Their parents had normal hearing and were both heterozygous carriers of the above variants. Both variants had co-segregated with the disease phenotype in the pedigree and were unreported previously. CONCLUSION Pathogenic variants of the TRIOBP gene comprise an important factor for NSHL. The novel c.5185-2A>G and c.3299C>A variants discovered in this study have enriched the mutational spectrum of the TRIOBP gene and enabled molecular diagnosis and genetic counseling for the family.
Deafness/genetics* ; Hearing Loss, Sensorineural/genetics* ; Heterozygote ; Humans ; Microfilament Proteins/genetics* ; Mutation ; Pedigree ; Whole Exome Sequencing