[Nonsyndromic deafness due to compound heterozygous mutation of the CDH23 gene]

Objective:To identify the pathogenic gene mutation of two patients with non-syndromic deafness（NSHL）. Methods:Two patient with NSHL and their parents were selected in the research object. Each participant provided 3-5 mL of peripheral venous blood, which was used to establish a DNA library. Next generation sequencing was used to detect the sequence of the patient's genome, and the sequencing results were compared with the human genome sequence （GRCh）37/hg19. Sanger sequencing was used to verify the parents' genome sequence. Finally the patient's pathogenic gene mutation was confirmed.Amino acid conservatism and single nucleotide polymorphisms of the mutant sites were analyzed using a variety of databases and software. Results:The mutation was located to CDH23 gene in the chromosomal location 10q21-q22. Complex heterozygous mutations consist of c. 1343T>C and c. 7991_7993delTCA. Parents are heterozygous carriers of a single mutation. Conclusion:The next generation sequencing technology were used to screen the pathogenic gene mutation of inherited deafness. Combined with the genetic sequencing results of parents, the specific pathogenic gene mutation of deafness patients can be identified. While the pathogenicity of complex heterozygous mutation were explained by various pathogenicity analysis methods.