Strc, encoding stereocilin, is a gene located on chromosome 15q15.3. The loss of the stereocilin protein, encoded by this gene, induces the loss of connection between outer hair cells and tectorial membrane, only affecting outer hair cell (OHC) function and involving deficits of active cochlear frequency selectivity and amplifier functions despite normal inner hair cell preservation [4].

Mutations in the STRC gene are a major cause of mild-moderate autosomal recessive non-syndromic hearing loss (ARNSHL), with a pooled prevalence of DFNB16 in GJB2-negative patients with hearing loss being 4.08% (95% CI: 0.0289-0.0573), and the proportion of STRC variants in the mild-moderate hearing loss group being 14.36% [1]. In Japanese hearing loss patients, the prevalence of STRC-associated hearing loss was 2.77% [2]. In the Czech population, STRC gene mutations were found in 5.5% of all patients and 13.6% of patients with autosomal recessive non-syndromic hearing loss (NSHL-AR) [5]. Overall, STRC deletions are considered the second most common cause of mild-to-moderate hearing loss after the GJB2 gene [6]. In pediatric patients with biallelic pathogenic STRC mutations, all had bilateral, symmetric sensorineural hearing loss (SNHL), with baseline HL being mild in 39% of ears, moderate in 52%, and moderate-severe in 3%, and 58% had some degree of progressive HL [3].

In conclusion, the Strc gene is crucial for the normal function of the cochlear amplifier, as its loss of function leads to specific auditory deficits. Studies on STRC-related hearing loss across different populations have shown its significant contribution to mild-moderate hearing impairment, highlighting the importance of understanding Strc in the context of genetic hearing loss.