USH1C and retinitis pigmentosa 1: An interesting group of retinal disease genes can cause both syndromic and nonsyndromic phenotypes, not always with a clear disease mechanism: for example, USH2A mutations can cause the USH phenotype but also RP alone [4], [5], [6], [7], [8]; USH1C and MYO7A mutations have been associated with the USH phenotype but also hearing impairment alone [9], [10].