A Novel USH2A Variant in a Patient with Hearing Loss and Prenatal Diagnosis of a Familial Fetus: a Case Report and Literature Review

Abstract

Background: Usher syndrome (USH) is the most common cause of inherited deaf-blindness. This study aimed to identify pathogenic mutations in a Chinese patient with hearing loss and reviewed the relevant literature.Methods: Genomic DNA obtained from a five-year-old girl with hearing loss was analyzed via the disease-targeted gene panel. Results: We identified the compound heterozygous mutations c.8559-2A>G and c.4749delT in Usher syndrome type 2A (USH2A) gene as the underlying cause of the familial hearing loss; the former variation has been reported in the literature, but not the latter. The parents of the girl were heterozygous carriers. The two variants were pathogenic. Based on these findings, amniotic fluid samples were used for prenatal diagnosis of the couple's fetus, which was found to carry c.4749delT but not c.8559-2A>G variation. During the follow-up period of more than 9 months after the birth of the fetus, it was confirmed that the infant was healthy.Conclusions: We performed genetic diagnosis of Usher syndrome by disease-targeted gene panel and have proven that this method can serve as a rapid, high-throughput, and efficient screening strategy. The novel mutation expands the spectrum of USH2A variants in USH.