OBJECTIVETo determine the carrier rate for common mutations causing deafness among pregnant women in order to prevent births of deaf children.

METHODSFor 893 pregnant women, 2 mL peripheral venous blood was taken and DNA was extracted. A deafness DNA microarray screening was applied to such samples, and DNA sequencing was applied to husbands of women with positive screening results.

RESULTSA total of 40 carriers were detected, with the overall mutation rate being 4.48%. Among such carriers, GJB2 235delC was the most common heterozygous mutation (18 cases) and the mutation rate was 2.02%. GJB2 299A-T heterozygous mutation was detected in 7 cases with a mutation rate of 0.78%. IVS7-2A to G heterozygous mutation was detected in 9 cases with a mutation rate of 1.02%. There were 2 cases carrying GJB3 heterozygous mutation and 2 cases of mitochondrial 12S rRNA heterozygous mutation, with a mutation rate of 0.22%. IVS7-2A>G with GJB3 538C>T double heterozygous mutation was detected in 1 case, and IVS7-2A>G with GJB2 299A-T double heterozygous mutation was detected in another case, with the mutation rate of each being 0.11%. DNA sequencing has failed to find presence of mutations in the same gene in the husbands. The results of neonatal hearing follow-up were all normal.

CONCLUSIONApplications of the deaf genes screening in pregnant women may play prove to be valuable for the early detection for neonatal deafness.