GJB2 mutation spectrum in deaf population in a typical southeastern area of China

AbstractMutations inGJB2gene are the most frequently found mutations in patients with nonsyndromic hearing impairment. However, the spectrum and prevalence of mutations in this gene vary among different ethnic groups. In China, 30,000 infants are born with congenital hearing impairment annually. In order to provide appropriate genetic testing and counseling to the families, we investigated the molecular etiology of nonsyndromic deafness in 103 unrelated school children attending Nantong School for the Deaf and Mute in Jiangsu Province, China. The coding exon of theGJB2gene was PCR amplified and sequenced. Sixty twoGJB2mutant alleles were identified in 35.9% (37/103) of the patients. Twenty five patients carried two pathogenic mutations and 12 patients carried one mutant allele. The 235delC was the most common mutation accounting for 69.4% (43/62) ofGJB2mutant alleles. TheGJB2mutant alleles accounted for 30.1% (62/206) of all chromosomes responsible for nonsyndromic hearing impairment. Testing of the 3 most prevalent deleterious frame shift mutations in this cohort detected 100% of allGJB2mutant alleles. These results demonstrate that an effective genetic testing of GJB2 gene for patients and families with nonsyndromic hearing impairment is possible