This question is of importance as multiple mutations in NMNAT1 have been identified in patients with Leber congenital Amaurosis (LCA), another neurodegenerative disease targeting photoreceptors (Chiang et al., 2012; Falk et al., 2012; Koenekoop et al., 2012; Perrault et al., 2012). The gene discussed is NMNAT1; the disease is Leber congenital amaurosis.