DNAJC17 regulates RNA splicing in auditory hair cells and is required for hearing.

RNA splicing is essential for gene regulation, but its role in maintaining cochlear hair cell function remains incompletely understood. Here, we identify a heterozygous missense variant (c.401A>C, p.E134A) in DNAJC17, which encodes a spliceosome-associated protein, that segregates with adult-onset progressive hearing loss in a multigenerational family. Hair cell-specific deletion of Dnajc17 in mice results in profound deafness with progressive hair cell degeneration, establishing its essential role in cochlear maintenance. Hair cells lacking DNAJC17 exhibit marked stereocilia disorganization accompanied by widespread alternative splicing defects in the cochlea. Notably, the dual-specificity protein kinase Clk1 that regulates pre-mRNA splicing shows altered exon inclusion, consistent with disruption of splicing control networks. In addition, Dnajc17 p.E134A knock-in mice develop adult-onset progressive hearing loss with stereocilia and mitochondrial abnormalities but preserve hair cell survival, recapitulating the human phenotype. Together, these findings identify DNAJC17 as a causative gene for autosomal dominant hearing loss and identify RNA splicing regulation as a key mechanism required for long-term maintenance of cochlear hair cell integrity.