Cone-Rod Dystrophy 13
A number sign (#) is used with this entry because autosomal recessive cone-rod dystrophy-13 (CORD13) is caused by mutation in the RPGRIP1 gene (605446).
For a general phenotypic description and a discussion of genetic heterogeneity of cone-rod dystrophy, see 120970.
Clinical FeaturesHameed et al. (2003) reported 4 consanguineous Pakistani families with cone-rod dystrophy. Two of the families were large: 1 had 8 affected members over 2 generations, and the other had 8 affected members over 3 generations. The other 2 families had 2 affected sibs each. In all affected patients, there was deterioration in central vision and colorblindness from an early age, and rapid loss of vision between ages 14 and 16 years (visual acuity 1/60). Patients also had severe photophobia from childhood. Funduscopy showed a variable degree of fundus granularity and macular degeneration, and ERG showed involvement of both cones and rods.
MappingExclusion studies on the 2 large families with cone-rod dystrophy reported by Hameed et al. (2003) showed linkage to chromosome 14q11 (maximum lod = 5.17 and 4.21 for the 2 families, respectively, at marker D14S1023).
Molecular GeneticsIn a large Pakistani family with cone-rod dystrophy, Hameed et al. (2003) identified a homozygous mutation in the RPGRIP1 gene (605446.0005). Three additional affected Pakistani families had a different homozygous mutation in the RPGRIP1 gene (605446.0006).