NMNAT1 and retinal degeneration: Mice harboring Nmnat1 mutations (V9M and D243G) exhibit severe retinal degeneration while the most common LCA9 mutation (E257K), which is not fully penetrant (Siemiatkowska et al., 2014), induces a milder retinal degeneration phenotype (Eblimit et al., 2018; Greenwald et al., 2016).