A body of work on several mouse models has demonstrated that rod-cone photoreceptor degeneration in SCA7 is at least partially a consequence of interference of polyQ-expanded atxn7 with CRX, a homeodomain protein that plays a key role for proper transactivation of photoreceptor genes [27]–[30]. The gene discussed is ATXN7; the disease is spinocerebellar ataxia 7.