Rod-cone dystrophy in spinocerebellar ataxia type 1.

tein is possible. It is difficult to propose that the complete unilaterality of the disease in this patient is due to differences in environmental or genetic exposures between the two eyes. One possibility might be a somatic mutation in a progenitor cell during the development of the unaffected retinal tissue that ameliorates the effect of the mutation. To conclude, this represents the first report to our knowledge of unilateral disease occurring in a patient with a germline mutation for a known RP-associated variant. The phenotype, even when investigated carefully, is entirely normal in the unaffected eye. A somatic, embryonic mutation causing mosaicism at this locus is proposed.