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

Background Hearing 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. Methods A 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. Results A 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 v ariants (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. Conclusion This 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.