ATXN7 and spinocerebellar ataxia 7: It has been postulated that retinal degeneration in SCA7 may be associated with an abnormal interaction between the expanded ataxin-7 and CRX as potentially binding the expanded polyQ tract in ataxin-7 to a glutamine-rich region in CRX (La Spada et al., 2001; Yoo et al., 2003; Kumar and Pulido, 2011).