Mutation analysis and early pregnancy prenatal diagnosis for two families affected with non-syndromic hearing loss

Abstract

Objective:The aim of this study is to identify the pathogenic genes of two non-syndromic hearing loss families, provide accurate genetic counseling and early pregnancy prenatal diagnosis services for second birth families, which determine the genotype of the fetus, early diagnosis and early intervention to prevent the birth of deaf children. Method:Two families with a severe sensorineural hearing loss were enrolled in this study. Genomic DNA was extracted from the peripheral venous blood of the proband and parents. The mutations of the four hearing loss susceptibility genes were analyzed by the hereditary hearing loss gene detection kit (PCR reverse hybridization) and Sanger sequencing. After confirming the genotype of the subject, the genotype of the fetus was examined for the fetus with 10 to 12 weeks of gestation, and the neonates were diagnosed with prenatal diagnosis. Result:In the two families, the No. 1 family proband was the compound heterozygous mutation of SLC26A4 gene c.IVS72A＞G/c.2177insCTAT, and parents were carriers. The prenatal diagnosis showed that the fetal genotype of No. 1 family was a compound heterozygous mutation, and the fetus was not born. The No. 2 family proband genotype was the compound heterozygous of GJB2 gene c.605ins46/c.512insAACG, and the parents were both carriers. The No. 2 family, the prenatal diagnosis showed the fetal genotype of No. 2 family GJB2 gene sequence was normal, the newborn passed the hearing screening. Conclusion:Genetic testing of hereditary hearing loss combined with prenatal diagnosis plays a significant role in guiding deaf children with re-fertility needs, especially prenatal diagnosis in early pregnancy, which can achieve early diagnosis, early detection and early intervention, effectively reducing the birth rate of children with deafness.