The CLRN2 gene belongs to the clarin family of genes. The Clarin (CLRN) proteins belong to a superfamily of small integral proteins with four alpha-helical transmembrane domains, which also includes Tetraspanins, Connexins, Claudins, Occludins and calcium channel gamma subunit-like proteins. In humans, the CLRN family comprises three proteins encoded by the paralogous genes CLRN1, CLRN2 and CLRN3, which contain no known functional domains apart from their four transmembrane domains and a C-terminal class-II PDZ-binding motif (PBM type II). In humans, CLRN1 mutations have been found to cause Usher syndrome type 3A (USH3A), which is characterized by post-lingual, progressive hearing loss, variable vestibular dysfunction and onset of retinitis pigmentosa leading to vision loss.