CRX-linked macular dystrophy with intrafamilial variable expressivity

Background: We present a macular dystrophy of differing severity in a single kindred caused by a heterozygous nonsense mutation in CRX. Case report: A 21 year old Caucasian male from a Swiss family was investigated for decreasing central visual acuity associated with dischromatopsia. Clinical examination revealed posterior pole atrophy, including the maculopapillary bundle. Multimodal imaging, including autofluorescence, showed a hyperautofluorescent paramacular ring in both eyes. Genetic analysis identified a c.313C > T, p.Q105* nonsense mutation in CRX. The same mutation was identified in his father and uncle. Both of them showed signs of the disease, however with different severity. Conclusion: We describe an intrafamilial variable expressivity of a CRX mutation causing an isolated macular dystrophy.