CHM and choroideremia: Indeed a mutation in the seed region of microRNA-204 has been found to segregate in a family with autosomal dominantly inherited retinal dystrophy and bilateral coloboma (44), a 5’UTR sequence in the NMNAT1 gene has been implicated in a form of LCA (45) and recently a single base mutation in the promoter region of the CHM gene has been implicated as causative of choroideremia (46), all highlighting the potential role of regulatory mutations in some forms of IRD.