Interestingly, deletions involving the 5' portion of the EXOC6A gene and two adjacent cytochrome p450 genes (CYP26A1 and CYP26C1) are associated with autosomal-dominant nonsyndromic optic aplasia (ONA), an extremely rare disorder that causes unilateral or bilateral blindness in the affected eye (Meire et al., 2011). This evidence concerns the gene CYP26A1 and Blindness.