USH2A and retinitis pigmentosa 1: Mutations in the gene for Usher syndrome 2A (USH2A) are causative for non-syndromic recessive retinitis pigmentosa (RP) [1-4] and for Usher syndrome type II (USH2), a recessive disease characterized by congenital moderate to severe stable hearing loss, and RP that often leads to blindness [5].