The Analysis Of GJB2Gene, GJB3Gene, SLC26A4Gene And Mitochondrial12S RRNA Gene Mutations In Non-syndromic Deafness Patients

Aim:Our study is to establish a clinical examination detecting common deafness genes such as GJB2gene, GJB3gene, SLC26A4gene and mitochondrial12S rRNA gene mutations. Simultaneously we tried to study deafdisease via molecular etiology toward non-syndromic deafness patients. This study is helpful to closely match theotologist and hearing rehabilitation workers in the identification of deafness etiology, determine newborn hearing, guide therapy and daily behavior, establish prevention programs, and provide genetic counseling and prenatal guidance and diagnostics.Methods:1:Object information acquisitionWe have established extremely detailed medical records. All cases were examined by pure tone audiometry. Systemicand ENT routine examinations were also applied. Because a part of patients was too young to collaborate, they were examined with two kinds of objective hearing tests of tympanometry and auditory brainstem response detection. Moreover, before operation was conducted the patient was examined with the clinical imaging CT and MRI.5ml venous blood was collected in all cases.2:Genomic DNA extractionNucleic acid extraction kit of Qiagen was used to extract genomic DNA from whole blood.3:PCR amplification and hybridization Human genomic DNA was used as a template. The related gene fragments were amplified and fluorescently labeled via specific primers with Tag. Then the products were hybridized with common gene chip which can identify the corresponding label sequence.4:Gene mutation detectionMicroarray scanner (JingXin LuxScanTM10K-B) and the corresponding genetic deafness gene chip detection system were used to examine gene mutations of GJB2gene, GJB3gene, SLC26A4gene and mitochondrial12S rRNA gene.ResultsIn179cases,79cases have mutations in detected genes with different degrees. In159cases of congenital severe sensorineural deafness,48cases (26.80%) are because of the mutations in detected genes. In179cases,(1)42cases have GJB2gene mutation including2cases with GJB235del G-point mutation,0cases with homozygous mutation and2cases with heterozygosity mutation;(2)8cases have GJB2176del16mutation including1cases with homozygous mutation and7cases with heterozygosity mutation;(3)37cases have GJB2235del C mutation including17cases with homozygous mutation,20cases with heterozygosity mutation;(4)9cases have GJB2299del AT mutation including1cases with homozygous mutation and8cases with heterozygosity mutation. In29cases, the patients with congenital deafness were due to GJB2gene mutation.(5)38cases have SLC26A4gene mutation including7cases with2168A>G mutation,0cases with homozygous mutation and7cases with heterozygosity mutation;(6)34cases have IVS7-2A>G mutation including13cases with homozygous mutation and21cases with heterozygosity mutation. In16cases, combined with imaging findings the patients with congenital deafness were due to SLC26A4gene mutations.(7)3cases have mitochondrial12S rRNA gene mutation including2cases with1555A> G homogeneous mutation and1case with1494C> T homogeneous mutation. The patients have used aminoglycoside antibiotics.(8) No GJB3mutation. Based on gene level diagnosis,48cases were confirmed that they are genetic deafness. They have26.80%in all cases.31cases are genetic deafness mutation carriers, accounting for17.32%.ConclusionThe screening in GJB2gene GJB3gene, SLC26A4gene and mitochondrial12S rRNA gene mutation can help us understand or indicate some of the non-syndromic deafness. Therefore, GJB2gene GJB3gene, SLC26A4gene and mitochondrial12S rRNA gene should be the most common autosomal recessivedeafness-related genes and may be applied to deafness prenatal diagnosis and routine newborn genetic screening. This screening can provide much more accurate genetic counseling and intervention, thus achieve the anti-deaf to guide rehabilitation, assess deafness prognosis and reduce the rate of deafness occur. Molecular diagnostic techniques can be used to discover the cause leading to deafness and high risk factors. Following targeted intervention is applied. These will become an important approach to improve the quality of the population.