Objective: To develop a rapid genetic diagnosis technique for the patients with hereditary hearing loss by screening hot spots of mutations, namely 235delC of the GJB2 gene, IVS7-2A>G of the SLC26A4 gene, and 1555A>G of mitochondrial 12S rRNA.
Methods: Multiple PCR amplification of the three fragments covering the expected mutations in GJB2, SLC26A4 and 12S were carried out and the amplified products were analyzed by restriction fragment length polymorphism (RFLP).
Results: Eighteen homozygous and 18 heterozygous 235delC, 2 homozygous and 13 heterozygous IVS7-2A>G, and 8 homogeneous 1555A>G were detected in the 200 patients with hearing loss. All the results were confirmed by sequencing. The detection rate of the three mutant alleles was 21.7% (71/400 + 8/200 = 0.217) and the genetic diagnosis rate was 14% [(18+2+8)/200 = 0.14].
Conclusion: It is a convenient, efficient and economical method to screen the hot spots of mutation in the patient with hereditary hearing loss by using PCR-RFLP.