Moreover, if the ERG abnormalities in Beagles have the same cause as cord1 in MLHDs, the region could be further narrowed to 0.51 Mb and contain 14 genes (11 known and three unknown) other than RPGRIP1. Given its role in human and mouse retinopathies, RPGRIP1 remains a strong positional and functional candidate gene, and the insertion in exon 2 is so far the most likely mutation associated with PRA in MLHDs. This evidence concerns the gene RPGRIP1 and retinal disorder.