USH1C and hypotrichosis 1: While there is strong genetic evidence to support that this is a major activity in Caenorhabditis elegans (5), the non-helicase C-terminal extension of the protein, which comprises two harmonin-like domains (35), a PIP box and the cystein-rich RING domain—often affected by point mutations in HHS patients (7,10), is exclusively found in vertebrates.