A Hospital-Based Concurrent Hearing and Genetic Screening Study of 39,282 Newborns in Southwest China

BackgroundHearing loss is a significant public health concern. This study assessed the carrier frequency of deafness-associated genetic variants and the yield of concurrent newborn hearing and molecular genetic screening in Chongqing, China.MethodsA total of 39,282 newborns underwent hearing screening using both transiently evoked otoacoustic emission (TEOAE) and automated auditory brainstem response (AABR). Additionally, genetic testing was performed via PCR and flow-through hybridization to detect variants in four key deafness-associated genes: GJB2, GJB3, SLC26A4, and mtDNA. Positive results were confirmed by Sanger sequencing. Follow-up telephone interviews were conducted to monitor auditory status, with objective audiological evaluation recommended for screen-positive newborns.ResultsA total of 1,422 newborns carried at least one genetic variant, with a positive genetic screening rate of 3.62%. The most common variant was GJB2 c.235delC, found in approximately 48.80% of carriers. The carrier frequencies for the other genes were GJB2 (2.184%), SLC26A4 (1.018%), GJB3 (0.168%), and mtDNA (0.204%). Four newborns with biallelic GJB2 variants (one homozygous c.235delC and three compound heterozygous c.235delC/c.299_300delAT) had moderate hearing loss and were fitted with hearing aids. In addition, one newborn with compound heterozygous SLC26A4 variants (c.919-2A>G and c.2162C>T), identified by follow-up Sanger sequencing, also had moderate hearing loss and received hearing aids. Fifteen newborns carried heterozygous variants in two different recessive deafness genes and had normal hearing at follow-up; Seventy-seven newborns carried mitochondrial variants associated with aminoglycoside ototoxicity and received drug-warning cards.ConclusionThis hospital-based, single-center study characterizes the carrier frequencies of 13 common deafness-associated variants in a voluntary-participation cohort in Chongqing, China. The findings are restricted to the specific variants examined and may not be generalizable to the entire newborn population of Chongqing.