Genetic screening of mutation hot-spots for nonsyndromic hearing loss in southern Jiangsu province with SNaPshot / 中华医学遗传学杂志

ABSTRACT

<p><b>OBJECTIVE</b>To investigate the mutation frequency in 7 mutation hot-spots of deafness gene in southern Jiangsu province and verify the performance of the SNaPshot technology platform, designed for genetic screening of non-syndromic hearing loss (NSHL) in Chinese.</p><p><b>METHODS</b>One hundred and twenty-five NSHL patients were enrolled. Amplification of 235delC, 299-300delAT in GJB2 gene, IVS7-2A>G, 2168 A>G in SLC26A4 gene, and 1555A>G, 7445 A>G and 3243 A>G in mitochondrial DNA (mtDNA) was performed using multiplex polymerase chain reaction (PCR) technology. Afterwards, the sequence-specific probe interrogated each locus and labeled it at the 3' end using fluorescent dideoxynucleotide chemistry by the SNaPshot Multiplex Kit, the resulting products were then separated electrophoretically in ABI PRISM R 3130 Genetic Analyzer and analyzed in the presence of a fifth-dye-labeled size standard. Finally, the genotyping results were verified by direct sequencing or PCR-restriction fragment length polymorphism (PCR-RFLP).</p><p><b>RESULTS</b>(1) The total mutation frequency for the 7 mutation hot-spots was 53.6%. The mutation frequency of 235delC was 24.0%, 299-300delAT was 5.6% in the GJB2 gene, IVS7-2A>G was 15.2%, 2168A>G was 3.2% in the SLC26A4 gene. The mutation frequency of 1555A>G and 7445 A>G in mtDNA was 4.8% and 0.8% respectively. The mutation 3243 A>G was not detected. (2) The SNaPshot results were consistent with that from direct sequencing or PCR-RFLP, and the specificity and sensitivity of detection were 100%.</p><p><b>CONCLUSION</b>(1) More than half of the patients with deafness in southern Jiangsu province carry the mutations of the seven hot-spots. (2) The genetic screening technology platform based on SNaPshot can detect 7 mutations in one reaction, and is efficient and suitable for clinical practice.</p>