The rs29358506 SNP in the third exon 3 of Cs gene (11 exons, cDNA 1395 nt, encoding 464 amino acids) is the root cause of ahl 4-related hearing impairment which resulted in a missense mutation (H55N) of Cs. Our previous studies have shown that the mRNA levels of apoptosis-related genes (caspase-3 and caspase-9, etc.)were increased in inner ears of A/J mice at postnatal day 1, and anti-apoptosis treatment can reduce the hearing threshold of A/J mice to some extent. This evidence concerns the gene CS and Hearing impairment.