Abstract: Background: The high prevalence of hearing loss in China is associated with a high carrier rate of pathogenic variants in genes for hearing loss. At present, there is a lack of screening data on carriers of pathogenic genes for hearing loss among newborns in neonatal intensive care units (NICU). Objective: To investigate the carrier rate of GJB2 and SLC26A4, pathogenic genes for hearing loss, in NICU newborns. Design: Cross-sectional survey. Methods: Newborns were enrolled in the NICU at Children's Hospital of Fudan University from January 2016 to December 2021, with admission days≤28 d and high-throughput sequencing completed before discharge. Those with positive hearing-loss-associated genetic findings after birth were excluded. The sex, gestational age and birth weight were collected from electronic medical records. The number of cases identified with pathogenic variants in GJB2 and SLC26A4 and the standard terminology of the human phenotype of the children were extracted from the sequencing database. Carrier rate(%)=the number of heterozygous pathogenic or likely pathogenic (P/LP) variants/total number of study subjects. PubMed, Embase, and Wanfang databases were searched. Literature that previously reported the carrier status of the GJB2 gene and/or SLC26A4 gene P/LP mutations in NICU patients, newborns and pregnant women in China were included and reviewed. Main outcome measures: Carrier rate of P/LP variants in the GJB2 gene and SLC26A4 gene. Results: A total of 14 924 neonates were included, including 8 587 males (57.5%) and 6 337 females, with a gestational age of (35.6±3.7) weeks and a birth weight of (2 711.7±887.1) g. A total of 18 heterozygous P/LP mutations were detected in 2 009 children (13.462%) carrying P/LP mutations of the GJB2 gene, among which c.109G>A was the most common (10.902%), followed by c.235del (1.749 %), c.299_300del (0.409%), c.176_191del (0.154%), c.508_511dup (0.074%) and c.257C>G. There were 305 children (2.044%) carrying P/LP mutations of the SLC26A4 gene. A total of 31 heterozygous P/LP mutations were detected, and the six highest carrier rates were for c.919-2A>G (1.139%), c. .2168A>G (0.181%), c.1226G>A (0.100%), c.1229C>T (0.094%), c.1174A>T (0.080%) and c.1003T>C, respectively. Conclusions: It is suggested that c.109G>A, c.508_511dup and c.257C>G on the GJB2 gene and c.1003T>C on the SLC26A4 gene should be included in the carrier screening for pathogenic genes for hearing loss among newborns in NICU.

Key words: Hearing loss, Newborn, Gene, GJB2, SLC26A4