GNAT2 and retinal degeneration: We screened the mutant Pde6brd1 (c.1041C > A) allele (22), two mutant alleles in the Gnat2 gene, Gnat2 (c.518A>G) (23) and Gnat2Cpfl3 (c.598G>A) (24), and the polymorphism in the Rpe65 gene, RPE65Met450Leu [Rpe65 (c.1348C>A)], that has been previously shown to be a genetic modifier for retinal degeneration (25).