TULP1 and retinitis pigmentosa 1: Besides clear phenotypic differences, different defects in the same gene may also be responsible for different clinical phenotypes, for example different variations in RPGRIP1 (MIM # 605446) are known to cause RP, LCA and CRD, TULP1 (MIM # 602280) mutations have been shown to cause RP, LCA or CD [4], and RPGR (MIM # 312610) variants are known to cause RP or CD [5].