Abstract
Purpose: :
To identify a mutation in a patient from a large 4–generation Wisconsin family with a history of macular dystrophy and retinitis pigmentosa (RP).
Methods: :
A 54–year–old Caucasian female from a 4–generation Wisconsin family with a history of adult onset macular dystrophy and RP was enrolled in our study. A clinical diagnosis of adult–onset macular dystrophy was made on the basis of a medical examination when the patient was 43. The disease has shown a slow progression. Other family members were invited to partake in the study, unfortunately they were either deceased or chose not to participate. Because of this, the disease status of other family members was based on a questionnaire answered by the enrolled patient and could not be independently confirmed. For exon scanning, genomic sequences for VMD2 and RDS–peripherin were evaluated (http://genome.ucsc.edu), and primers were designed to anneal 50 bp away from intron exon junctions. PCR and sequencing were performed using standard methods.
Results: :
Initially due to the diagnosis of adult onset macular dystrophy, the affected patient was evaluated for mutations in the VMD2 gene. Exon scanning did not identify any mutations. Based on the family history of adult onset macular dystrophy, we also considered RDS–peripherin as the candidate gene. We identified a 1–base pair deletion 920delT in exon 3.
Conclusions: :
Mutations in the RDS–peripherin gene have been associated with dominant retinitis pigmentosa, progressive macular degeneration, digenic RP, and pattern dystrophies. We identified a 1–bp deletion 920delT found in the RDS–peripherin gene at codon 307 resulting in a premature stop codon in a patient with adult onset macular dystrophy from a Wisconsin family with history of macular dystrophy and RP. The same 920delT deletion has also been reported in a patient from Germany with typical clinical signs of progressive form of autosomal dominant retinitis pigmentosa (ADRP). Our Wisconsin patient is of German descent suggesting a possible founder effect. In spite of the identical mutation, clinical phenotypes in these patients are distinct suggesting that the genetic background may be playing a critical role. We are currently investigating if a mutation in the ROM1 gene may also be playing a role in the disease phenotype of the Wisconsin patient.
Keywords: retinal degenerations: hereditary • retina • genetics