ABSTRACT
Objective To investigate the prevalence of GJB2 ,SLC26A4 and mitochondrial DNA 12S rRNA m .1555A>G(mtDNA 1555A>G) mutations in Hui ethic group patients with nonsyndromic hearing loss (NSHL) from Northwest China .Methods A total of 420 peripheral blood samples were collected from unrelated Hui ethic group probands with NSHL in Northwest China .Amplified the target gene by polymerase chain reaction (PCR) af-ter extracting genomic DNA from whole blood .The mtDNA 1555A>G mutation was detected by PCR -Alw26I di-gestion ,then direct sequencing was used to the positive samples of mtDNA 1555A> G ,the coding region of GJB2 gene ,exon 8 and 19 of SLC26A4 gene .Results There were 11(2 .62% ) cases caused by mtDNA 1555A>G homo-zygous mutation in 420 patients with NSHL .There were 41(9 .76% ) cases including homozygote and compound het-erozygote ,caused by GJB2 gene mutation ,which was the most frequent deafness -related gene .The allel frequency of c .235delC accounted for 6 .90% ,as well as the most frequent(51 .33% ) mutational pattern in GJB2 gene .There were 20 patients(4 .76% ) were found carring two allel mutations in SLC26A4 gene .The allel frequency of c .919 -2A>G was 5 .0% ,accounting for a total of 68 .85% in all base alterations of SLC26A4 gene ,which was the major mutant form of SLC26A4 gene .Conclusion GJB2 gene is the most common deafness -gene in Hui ethnic group pa-tients with NSHL from Northwest China ,while c .235delC is the main mutant form ,and c .919-2A>G is the hot-spot mutation of SLC26A4 gene .Through this study we can provide the molecular epidemiology basis for Hui ethnic group patients with NSHL from Northwest China in genetic diagnosis ,genetic counseling and therapy by associated testing of three frequent hearing loss genes .
ABSTRACT
Objective To study the SLC26A4 mutations in children with non -syndromic hearing loss by ge-netic testing method ,for the purpose of investigating etiology and mutation regularity of hearing loss ,and to provide basic information for the molecular diagnosis of hearing loss .Methods Blood samples and clinical data of 137 spo-radic cases with non -syndromic hearing loss and 126 normal controls were collected .The SLC26A4 gene of the pa-tients and normal controls were amplified by polymerase chain reaction (PCR) ,then subjected to automatic DNA se-quencing .Results Pathologic SLC26A4 mutations were identified in 23 out of 137 patients ,and in 23 out of 119 bi-lateral deafness ,mutate rate were 16 .79% and 19 .33% ,respectively .SLC26A4 mutations were identified in 19 out of 20(95% ) patients with bilateral LVA .A total of 11 mutations were identified in the present study ,including 4 novel mutations (E29K(c .85G>A) ,R79X(c .235C> T) ,C282G(c .844T>G) ,V285I(c .853G>A) )and 7 repor-ted mutations .In the present study ,IVS7-2A>G was the most common mutation ,and was detected in 19 out of 23(82 .61% ) patients with SLC26A4 mutations .Conclusion SLC26A4 mutations ,the common reason for non -syndromic hearing loss ,were closely related with LVA .IVS7-2A>G was the most common mutation in SLC26A4 mutant .