Objective: To discuss how to determine the number of samples in epidemiological study about deafness genes and reveal the characteristics of GJB2, SLC26A4 and mitochondrial DNA A1555G mutations in deaf-mute patients in schools for deaf-mutes in Shandong Province.
Methods: A total of 485 subjects were collected from the different schools for deaf-mutes in Shandong province. Amplified target fragments included GJB2 coding sequence, mtDNA12SrRNA and exon 8, 10, 17, 19 of SLC26A4 gene. The amplicons of mtDNA 12S rRNA were subjected to restriction enzyme Alw26I. The amplicons of patients whose enzyme reaction highly indicating A1555G mutation, amplicons of GJB2 and those exons PCR products of SLC26A4 were directly sequenced.
Results: The study revealed that 36.29% patients had two mutated alleles (homozygote & compound heterozygote) of GJB2 (24.12%) and SLC26A4 (6.60%) and mtDNA12SrRNA A1555G (5.57%). The 235delC and IVS7-2A > G were still the mutational hot spot in GJB2 and SLC26A4 respectively.
Conclusion: The method of determining the number of sample is very important in the epidemiological study. There were about 24 thousand deaf-mute patients who were caused by three sensitive deafness genes mutations in Shandong province. Screening the sensitive deafness genes in newborn is imminent.