Screening for hotspot mutations associated with genetic hearing impairment in pregnant women and subsequent prenatal diagnosis in high risk pregnancies

Abstract

Objective: To screen for hotspot gene mutations associated with genetic deafness in Chinese pregnant women, and to perform risk assessment and prenatal diagnosis in high-risk families. Methods: Between November 2012 and October 2017, 26 117 pregnant women were screened by molecular hybridization microarray for 9 hot-spot mutations in 4 hereditary deafness related genes (GJB2 c. 35 del G, c. 176_191 del 16 bp, c. 235 del G, c. 299_300 del AT, GJB3 c. 538 C>T, SLC26A4 c. 2168 A>G, IVS 7-2 A>G, mitochondrial DNA 12S rRNA m. 1494 C>T, m. 1555 A>G). Genotype analysis was carried out in husbands of women carrying mutations, and prenatal diagnosis was carried out in the fetuses with high risk of deafness. Results: Among all women tested, 1 208(4.63%) were carriers of genetic deafness mutations, 7 with hearing impairment were affected by homozygous or compound heterozygous mutations, 51 were mitochondrial gene mutation carriers, 103 were carriers of GJB3 c. 538 C>T heterozygous mutation, 1 026 were carriers of GJB2 or SLC26A4 heterozygous mutations, and 21 carried heterozygous mutations in two genes simultaneously. In 394 families, the husbands accepted gene sequence testing, and 27 in which were determined as carriers of mutations in identical genes as their wives. Among which, 18 families received prenatal diagnosis, and 5 fetuses were diagnosed as hereditary deafness. In 9 families who did not receive prenatal diagnosis, 1 neonate was diagnosed as compound heterozygote after delivery. Conclusion: In order to prevent birth defects with congenital hearing problems, it is effective to provide screening for hotspot mutations in pregnant women and to perform prenatal diagnosis on high risk pregnancies.