Autosomal dominant cone-rod dystrophy associated with mutations in codon 244 (Asn244His) and codon 184 (Tyr184Ser) of the peripherin RDS gene

Objective: To characterize clinical findings associated with mutations in codon 244 (Asn244His) and codon 184 (Tyr184Ser) of the peripherin/RDS gene. Design: Case reports with clinical features and results of fluorescein angiography, electroretinography, kinetic visual field resting, and DNA analysis. Setting: University medical center. Patients: Four affected members of two Japanese families with autosomal dominant cone-rod dystrophy associated with transversion mutations in codon 244 (Asn244His) and codon 184 (Tyr184Ser) of the peripherin/RDS gene. Results: Characteristic features included the initial symptoms of decreased visual acuity, macular degeneration, central or paracentral scotoma, cone-mediated electroretinographic responses that were more impaired than rod-mediated responses, and pigmentary degeneration in the midperipheral retina in the late stage. These phenotypic features corresponded to cone-rod dystrophy type 2a by the classification of Szlyk and associates. Conclusions: The Asn244His and Tyr184Ser mutations in the peripherin/RDS gene cause cone-rod dystrophy type 2a. These findings imply that a mutation in codon 244 or codon 184 of the peripherin/RDS gene affects the functions and/or structural stability of cones and rods.