Two point mutations of Crx, R41W and E80A, that cause cone-rod dystrophy in humans and lie within the homeodomain but outside the NLS did not disrupt the nuclear localization of Crx protein, but a R90W mutation of Crx that causes human Leber congenital amaurosis (LCA) and resides within the NLS resulted in the fusion protein localized in both nuclei and cytoplasm in majority (51% to 69%) of the transfected cells.