OBJECTIVETo identify mutation of GJB2 gene and provide genetic counseling for a family affected with keratitis-ichthyosis-deafness (KID) syndrome.

METHODSGenomic DNA was extracted from peripheral blood samples with a standard phenol-chloroform method. PCR and Sanger sequencing were used to analyze potential mutation in the proband. Suspected mutation was verified with a PCR-high-resolution melting (PCR-HRM) method. T-clone sequencing was applied to determine the parental origin of the mutation.

RESULTSA heterozygous mutation, c.148G>A (p.Asp50Asn), which is located in the exon 1 of the GJB2 gene, was found in the proband. The results was confirmed by HRM analysis. Cloning sequencing suggested that the mutation was derived from the father's germline.

CONCLUSIONThe hot-spot mutation c.148G>A (p.Asp50Asn) in the GJB2 gene probably underlies the KID syndrome in this Chinese family. A PCR-HRM method has been established to rapidly detect common mutations associated with this disease.

Child ; Connexins ; genetics ; DNA Mutational Analysis ; Humans ; Keratitis ; genetics ; Male ; Mutation ; Pedigree

OBJECTIVE: To determine the frequencies of deafness gene mutations among patients with non-syndromic hearing loss (NSHL) from northern Jiangsu province. METHODS: A total of 117 patients with NSHL were enrolled. The coding region of GJB2 gene, IVS7-2A>G and 2168A>G mutations of SLC26A4 gene, and 1555A>G and 1494C>T mutations of mitochondrial DNA 12S rRNA were subjected to Sanger sequencing. Patients in whom no mutation was detected were further tested by targeted gene capture and high-throughput sequencing. RESULTS: Among the 117 patients, 86 (73.50%) were found to carry mutations. GJB2 gene mutations were found in 61 patients (52.14%), including 22 (18.80%) with homozygous mutations and 39 (33.33%) with heterozygous mutations. SLC26A4 gene mutations were found in 19 patients (16.24%), including 4 (3.42%) with homozygous mutations and 15 with heterozygous mutations (14.53%). Mitochondrial 12S rRNA gene mutation was found in 6 patients (5.13%). Targeted gene capture and high-throughput sequencing of 8 patients identified 4 further cases, including 1 with RDX gene 129_130del and 76_79del compound heterozygous mutations, 1 with OTOF gene 1274G>C homozygous mutation, 1 with SLC26A4 gene 919-2A>G and IVS16-6G>A compound heterozygous mutation, and 1 with SLC26A4 gene 919-2A>G and A1673T compound heterozygous mutation. CONCLUSION The frequency of mutation among patients with NSHL from north Jiangsu was 73.50%, and GJB2 gene was most commonly mutated.
China ; Connexins ; DNA Mutational Analysis ; DNA, Mitochondrial ; Hearing Loss ; genetics ; Humans ; Membrane Proteins ; Mutation ; Sulfate Transporters

OBJECTIVETo analyze the coding sequence of GJB2 gene in six pedigrees with nonsyndromic hearing loss in order to find deafness-causing mutations in the GJB2 gene, and to explore the inherent pattern of deafness-causing mutations in the GJB2 gene.

METHODSGenomic DNA was extracted from peripheral blood for the probands and their family members. Coding sequence of the GJB2 gene was amplified by polymerase chain reaction, sequence variations were determined by DNA sequencing. Amplified fragments with overlapping peaks on sequencing chromatogram were sequenced by TA cloning in order to determine whether the mutations originated from the same allele.

RESULTSMutations in the GJB2 gene were found in 4 out of the 6 pedigrees with nonsyndromic hearing loss. Four types of mutations were detected in the GJB2 gene, which were 235delC, 299-300delAT, 79G>A+341A>G, and 109G>A. Compound heterozygous polymorphisms 79G>A and 341A>G, and mutations 109G>A and 235delC had deafness-causing effects.

CONCLUSIONHeterogeneous mutations of the GJB2 gene are frequently seen in patients with nonsyndromic hearing loss. Sometimes, polymorphisms may cause deafness when they are combined. Environmental factors and other genes may contribute to hearing loss caused by the GJB2 gene mutations.

Base Sequence ; Connexin 26 ; Connexins ; genetics ; DNA Mutational Analysis ; Female ; Hearing Loss ; genetics ; Humans ; Inheritance Patterns ; genetics ; Male ; Pedigree

OBJECTIVE: To detect common pathogenic variants associated with congenital deafness among neonates from Huizhou and surrounding areas and discuss its implications. METHODS: Thirteen hot-spot mutations in four most common pathogenic genes were screened among 20 934 neonates from March 2017 to December 2019. RESULTS: In total 760 neonates were found to carry common pathogenic variants (3.63%). Sixty two neonates have carried homozygous/compound heterozygous variants or homoplasmy/heteroplasmy mutations of mtDNA (0.29%). Further analysis of five abnormal cases revealed that 3 of them have carried compound heterozygous mutations of GJB2 gene, and 2 were due to compound heterozygous variants of the CDH23 gene. CONCLUSION Genetic testing has a great clinical significance for the prevention and reduction of congenital hearing loss, but the scope needs to be updated and redefined by removing mutation sites with a very low rate, adding new significant sites, and improvement of the technical strategies.
Connexin 26 ; Connexins/genetics* ; DNA Mutational Analysis ; Deafness/genetics* ; Genetic Testing ; Hearing Loss/genetics* ; Humans ; Infant, Newborn ; Mutation ; Neonatal Screening

OBJECTIVE: To detect potential mutation in a pedigree affected with autosomal recessive non-syndromic deafness. METHODS: Mutation analysis was carried out by next generation sequencing, and suspected mutations were verified by Sanger sequencing. RESULTS: A heterozygous c.235delC mutation of the GJB2 gene, together with compound heterozygous mutations of the OTOF gene [c.1194T>A (p.D398E) and c.2180A>G (p.N727S)] were detected in the proband. The sister of the proband (also had hearing loss) has carried a heterozygous c.235delC mutation in the GJB2 gene, in addition with a heterozygous c.2180A>G(p.N727S) mutation of the OTOF gene. By Sanger sequencing, a heterozygous IVS1+2T>A mutation was further detected in the non-coding region of the GJB2 gene in both sisters. CONCLUSION The compound heterozygous c.235delC and IVS1+2T>A mutations of the GJB2 gene probably account for the hearing loss in the two sisters, among which IVS1+2T>A is considered as a novel pathogenic mutation of the GJB2 gene.
Connexins ; genetics ; DNA Mutational Analysis ; Female ; Hearing Loss, Sensorineural ; genetics ; High-Throughput Nucleotide Sequencing ; Humans ; Membrane Proteins ; genetics ; Mutation ; Pedigree

OBJECTIVE: To determine the possible gene mutation and its different sites that leads to hearing loss in a consanguineous marriage pedigree. METHOD: Blood samples from a Changchun pedigree were obtained with informed consent. Their genomic DNA were extracted from peripheral blood and PCR was performed. Nine of hot spot mutations in four most common deafness pathologic gene were detected with the DNA microarray, including GJB2, GJB3, PDS and mtDNA 12S RNA gene. At the same time, the results were confirmed with the traditional methods of sequencing. RESULT: GJB2 gene of 235 delC and 299-300 delAT compound heterozygous mutation was found in propositus. His father was 299-300 delAT homozygous mutation and mother was 235 delC homozygous mutation. In the relatives on the paternal side, the affected patients all were 299-300 delAT homozygous mutation and normal hearing member was 299-300 delAT heterozygous carrier. This GJB2 mutation come from grandparents of consanguineous marriage. CONCLUSION GJB2 gene mutation played on an important role in this deafness family. It is essential approach for genetic diagnosis of non - syndromic sensorineural hearing loss.
Connexin 26 ; Connexins ; genetics ; Consanguinity ; Deafness ; etiology ; genetics ; Female ; Heterozygote ; Humans ; Male ; Oligonucleotide Array Sequence Analysis ; methods ; Pedigree ; Young Adult

OBJECTIVE: To preliminarily determine the gene mutation frequency and the hotspots in Henan province, we analysed the deafness-related gene mutation in patients with non-syndromic hearing loss (NSHL). METHOD: Genomic DNA samples of 100 patients with NSHL in Henan province were extracted from peripheral blood after clinical history inquiry and clinical examination, Four common deafness genes GJB2, SLC26A4, mitochondrial 12SrRNA, and GJB3 were detected by Sanger sequencing method,and then data analysis were conducted. RESULT: Among 100 patients with NSHL. the gene mutation frequency was 44%. In these patients, 29 cases had GJB2 mutations, 13 cases had SLC26A4 gene mutations, and 3 cases had mitochondrial 12SrRNA mutations. CONCLUSION Among the patients with NSHL in Henan province, the most frequent mutation causing hereditary deafness was mutation in GJB2, followed by SLC26A4,and it will provide a theoretical basis to determine the etiology of deafness in Henan Province.
China ; Connexin 26 ; Connexins ; genetics ; DNA Mutational Analysis ; DNA, Mitochondrial ; genetics ; Deafness ; genetics ; Gene Frequency ; Humans ; Membrane Transport Proteins ; genetics ; Mutation ; RNA, Ribosomal ; genetics ; Sulfate Transporters

OBJECTIVE: To detect additional variants for newborn carriers of single heterozygous variants of the GJB2 or SLC26A4 gene by genechip analysis in Changsha area, and explore the variation spectrum of deafness-related genes in this region. METHODS: For 462 newborns carrying single heterozygous variants of the GJB2 or SLC26A4 gene, all exons of the genes were subjected to Sanger sequencing. The pathogenicity of the variants was analyzed by database and literature search. RESULTS: For 305 newborns carrying a heterozygous GJB2 variant, 143 (46.49%) were found to carry additional variants, including 29 (9.51%) with c.109G>A likely pathogenic variant, and 1 (6.48%) with c.551G>A pathogenic variant. Among 153 newborns carrying single heterozygous variant of the SLC26A4 gene, 2 (1.31%) were found with a c.281C>T variant, and 1 (0.65%) with a c.1547_1548ins pathogenic variant. Among 4 newborns simultaneously carrying GJB2 and SLC26A4 variants, two were found to carry c.109G>A and c.844T>C variants (clinical significance unknown), respectively. CONCLUSION For newborns carrying single heterozygous variants of the GJB2 or SLC26A4 gene by genechip analysis, the detection rate for other variants is quite high. Sanger sequencing can significantly improve the detection rate of high-risk newborns and enrich the variant spectrum of deafness genes.
Connexins/genetics* ; DNA Mutational Analysis ; Deafness/genetics* ; Genetic Carrier Screening ; Heterozygote ; Humans ; Infant, Newborn ; Mutation ; Oligonucleotide Array Sequence Analysis ; Sulfate Transporters/genetics*

OBJECTIVE: Using simultaneous multi-gene mutation screening to survey the molecular epidemiological basis of 355 patients with nonsyndromic hearing loss of Inner Mongolia Autonomous region, we can identify the causes of their deafness,and verify the new method for simultaneous multi-gene mutation screening. METHOD: Three hundred and fifty-five patients with severe non-syndromic deafness from Inner Mongolia Autonomous regior were included in the study. The SNPscan technology was used for screening the 115 spots mutations in three common deafness-related genes(GJB2, SLC26A4, MT-12S rRNA) of patients with nonsyndromic hearing loss of Inner Mongolia Autonomous region. RESULT: In 355 patients, there were 89 cases of deafness caused by mutatior (25.07%). 53 patients with the GJB2 mutations were found(14.93%), including 24 cases of homozygous mutations (6.76%), 29 patients (8.17%) of compound heterozygous mutations, and 3 cases (0.85%) of single heterozygous mutations. 33 patients with the SLC26A4 mutations were found (9.30%), including 15 cases of homozygous mutations (4.23%),18 patients (5.07%) of compound heterozygous mutations, and 5 cases (1.41%) of single heterozygous mutations. mtDNA12S rRNA A1555G mutation was found in 6 patients (1.69%). mtDNA12S rRNA 1494C>T mutation was not found. CONCLUSION SNPscan technology allows accurate, rapid and cost-effective diagnostic screening in patients with hearing loss for etiology investigation. The SNPscan technology can serve as a good diagnostic tool for large-scale genetic testing for hereditary deafness and should be widely applied.
China ; Connexins ; DNA Mutational Analysis ; methods ; Deafness ; genetics ; Genetic Testing ; methods ; Heterozygote ; Homozygote ; Humans ; Mutation ; Polymorphism, Single Nucleotide ; RNA, Ribosomal

OBJECTIVE: Investigate common deafness gene mutations in patients with severe and profound non-syndromic hearing loss in Liaoning in order to understand their hereditary etiologies and characteristics at the molecular level. METHOD: Peripheral blood samples were obtained and the DNA templates were extracted from 128 non-syndromic hearing loss patients who are sporadic in clinics. The deafness gene chip was applied to detect hot-spot deafness gene mutations including GJB2, GJB3, SLC26A4 and mitochondrial 12S rRNA. Deafness etiology questionnaires, pure tone audiometry, auditory brainstem response, tympanometry and temporal bone CT were also applied. RESULT: Various types of gene locus mutations were seen in 52 of the 128 patients (40.6%); (1) GJB2 gene mutations (n=22) included c. 235 del C homozygous mutation (n=10), c. 235 del C heterozygous mutation (n=5); c. 176_191 del 16 heterozygous mutation (n=l); c 35 del G heterozygous mutation (n=l); c. 235 del C/c. 299_300 del AT mutation (n=l), c. 235 del C/c. 176_191 del 16 mutation (n=l), c. 35 del G/c. 176_191 del 16 mutation (n=l); c. 299_300 del AT/c. 919-2 A>G mutation (n=l), c. 235 del C/c. 919-2 A>G mutation (n=l). (2) SLC26A4 gene mutations (n=30) included c. 919-2 A>G homozygous mutation (n=6), c. 919-2 A>G heterozygous mutation (n=17), c. 2168 A>G homozygous mutation (n=l), c. 2168 A>G heterozygous mutation (n=2), c. 2168 A>G/c. 919-2 A>G mutation (n=2), c. 919-2 A>G/GJB2 c. 235 del C mutation (n=2); (3) No GJB3 and mitochondrial 12S rRNA mutation. Genetic deafness was confirmed at the gene level in 24 cases (18.8%) and 28 patients (21.9%) were diagnosed as carriers of genetic deafness gene mutations. CONCLUSION Genetic deafness occupies a large population in deaf community in Liaoning. Molecular genetic screening for these mutations and genetic counseling are effective methods to prevent the occurrence of hereditary hearing loss and provide theoretical guidance.
Adolescent ; Child ; Child, Preschool ; China ; Connexins ; DNA Mutational Analysis ; Deafness ; genetics ; Female ; Genetic Testing ; Humans ; Infant ; Male ; Mutation