Recently, more than thirty mutations in the nuclear NAD+ biosynthetic enzyme NMNAT1 were identified in patients with autosomal recessive LCA type 9 (LCA9) (Falk et al., 2012; Perrault et al., 2012; Koenekoop et al., 2012; Chiang et al., 2012; Coppieters et al., 2015; Khan et al., 2018). Here, NMNAT1 is linked to Leber congenital amaurosis 9.