Cross-species validation of a human age-related hearing loss candidate KLHDC7B as essential for mammalian hearing

Although age-related hearing loss (ARHL) is the most common sensory loss in older adults, underlying mechanisms remain unclear. Recent genome-wide association studies (GWAS) linked variation in several genes with ARHL risk, including KLHDC7B, a gene of unknown function not previously linked to hearing. We demonstrate Klhdc7b is expressed exclusively in sensory hair cells in mouse cochlea. Utilizing two independent mouse knockout models (Klhdc7b^IMPC-/- and Klhdc7b^RegnΔ/Δ) we find that absence of Klhdc7b leads to severe early-onset, progressive hearing loss. Hair cells appear to develop normally, but outer hair cells are progressively lost from base-to-apex of the cochlea, a common pathology in ARHL. These results suggest KLHDC7B is required for maintenance rather than development, of auditory function. The validation in mouse of a human ARHL GWAS association suggests other novel candidates should be investigated. Our work provides two mouse models to study KLHDC7B function, and for development of therapeutic tools for ARHL.