Low frequency of GJB2 mutations in thirty-five students with hearing loss in Chinese consanguineous families

ObjectiveGJB2 mutation is recognized as the prevalent causes of non-syndromic hearing impairment (NSHI) worldwide. However, the mutation profiles of this gene are unknown in deafness probands in the consanguineous pedigrees in China. Therefore, this study aimed to characterize the forms and frequencies of GJB2 mutations in 35 students with hearing loss in the consanguineous families in Hubei province, Central China.MethodsGenomic DNA was extracted from blood samples of 35 students with hearing loss. The target fragments were amplified by polymerase chain reaction (PCR) and subjected to sequencing to identify sequence variations.ResultsSurprisingly, none of these probands harbored homozygous mutation in GJB2. Three GJB2 heterozygous mutations were identified: a single base pair substitution c.35G > T and c.139G > T, and a 2 bp deletion c.299-300delAT in three probands.ConclusionThe frequency of GJB2 mutation is relatively low in these consanguineous families, most of which were minorities. Our results suggest that screening for responsible genes other than GJB2 may be necessary for NSHI in these minorities.