There were no instances of two plausible disease-causing variants in a gene previously associated with RP, but two human retinal degeneration genes (ABCA4 and USH2A) each harbored a single plausible disease-causing variant (Thr1428Met ACG>ATG and Arg4192His CGC>CAC, respectively). This evidence concerns the gene ABCA4 and retinitis pigmentosa 1.