For example, defects in proteins associated with intraflagellar transport (e.g., IFT140, TULP1), Bardet-Biedl syndrome (e.g., BBS1, BBS2, ARL6), the transition zone ciliary gate (e.g., CEP290, RPGR), and photoreceptor-specific or general ciliary signalling proteins (ARL3, CNGA1, etc.)all include retinal dystrophy amongst their presentations12. This evidence concerns the gene RPGR and Bardet-Biedl syndrome.