No abstract

Mutations in MYO6 encoding an atypical myosin motor protein important for inner ear hair cell function have been associated with autosomal recessive (DFNB37) and autosomal dominant (DFNA22) types of hearing loss in a few families worldwide. After genome-wide linkage analysis, we identified a novel MYO6 mutation at the splice acceptor site of exon 7 (c.554-1G>A) in an extended German family with autosomal dominant postlingual non-syndromic hearing impairment. Analysis of blood-derived cDNA revealed different aberrantly spliced mRNAs caused by the mutation, which are predicted to severely interfere with protein function. Two of the family members underwent cochlear implantation at ages 53 and 65. Here, we present detailed clinical data of this family which suggest a favourable outcome of cochlear implantation in hearing-impaired individuals with a MYO6 mutation.

Members of the chromodomain-helicase-DNA binding (CHD) protein family are chromatin remodelers critically implicated in human pathologies, with CHD6 being one of its least studied members. Here, we discovered a de novo CHD6 missense mutation in a patient clinically presenting the rare Hallermann-Streiff syndrome (HSS). We used genome editing to generate isogenic iPSC lines and model HSS in relevant cell types. We show that CHD6 binds a cohort of autophagy and stress response genes across cell types. The HSS-mutation affects CHD6 protein folding and impairs its ability to recruit co-factors in response to DNA damage or autophagy stimulation. This leads to an accumulation of DNA damage burden and to senescence-like phenotypes. By combining genomics and functional assays, we describe for the first time a molecular mechanism for the chromatin control of autophagic flux and genotoxic stress surveillance that applies broadly to human cell types and explains HSS onset.