Currently, 92 CRX mutations have been reported (HGMD, professional 2017)4, consisting mostly of heterozygous missense/nonsense mutations, small deletions, duplications and insertions giving rise to a complicated range and severity spectrum of retinal phenotypes, extending from the mild Benign Concentric Annular Dystrophy and autosomal dominant macular dystrophy, to the much more severe LCA, RP and CRD. This evidence concerns the gene CRX and retinitis pigmentosa 1.