NMNAT2 and Leber congenital amaurosis: This is consistent with the known deleterious effects of complete loss of NAD production e.g. spontaneous knockdown of Nmnat2 triggers Wallerian degeneration in mouse neurons [22] and reduction of function mutations in NMNAT1 cause Leber’s congenital amaurosis [28] (a rapid photoreceptor degenerative disease resulting in blindness).