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Retinitis punctata albescens associated with the Arg135Trp mutation in the rhodopsin gene
E Souied1, G Soubrane, P Benlian
1Genetics Laboratory INSERM U-393, Hôpital des Enfants-Malades, Paris, France.
Purpose:
To screen for mutations in the rhodopsin, peripherin/RDS, and ROM1 genes in a family affected with retinitis punctata albescens. Because clinical heterogeneity was observed in this family, with some members affected with retinitis punctata albescens and one member affected with features typical of retinitis pigmentosa, we analyzed the apolipoprotein E gene to elucidate this unusual intrafamilial heterogeneity.
Methods:
The coding sequences of these genes were analyzed with a combination of single-strand conformation polymorphism and direct sequence analysis. Haplotypes of the apolipoprotein E gene were analyzed by polymerase chain reaction and enzymatic digestion.
Results:
The Arg135Trp mutation in the rhodopsin gene was observed in all affected members of this family, but no mutation was detected in the peripherin/RDS or ROM1 genes. The e4 allele of the apolipoprotein E gene apparently cosegregated with the albescens phenotype in this family.
Conclusions:
The albescent phenotype in retinal dystrophy appears to not be caused exclusively by a peripherin/RDS gene mutation, and we suggest that the apolipoprotein E gene may play a role in the albescent phenotype.