CRX and spinocerebellar ataxia 7: A few experimental studies have led to the specific hypothesis that the retinal phenotype in SCA7 can be seen as a result of interference with the action of the CRX gene, expressed predominantly in retinal photoreceptor cells and controlling the expression level of multiple photoreceptor-specific genes, including rhodopsin and the color opsins (La Spada et al., 2001).