RP1 and retinitis pigmentosa 1: The primary contributor to the high prevalence of RP1 mutations in dominant RP was a frameshift mutation in RP1 (NM_006269.1:c.2285_2289delTAAAT,p.Leu762fs) that was observed to segregate with disease in five dominant RP pedigrees, including one large pedigree with four affected members and several unaffected members, and was never observed in pedigrees with other conditions.