Clinical features of codon 172 RDS macular dystrophy - Similar phenotype in 12 families

Objective: To report the phenotype associated with the codon 172 RDS (gene for retinal degeneration slow) mutation in 11 separate families with an arg inine-to-tryptophan substitution with common ancestry, and 1 family with an arginine-to-glutamine transition. Patients: Screening for RDS gene mutations was performed in 400 subjects wi th autosomal dominant retinal degeneration. Twelve families were identified with a mutation in codon 172. Haplotype analysis was performed. Full ophth almic evaluation was performed, including electrophysiologic and psychophys ical investigation and imaging of autofluorescence using confocal laser sca nning ophthalmoscopy. Results: Haplotype analysis demonstrated that the 11 families were ancestra lly related. All 12 families showed a common phenotype of macular dysfuncti on, with the deficit increasing with age. Abnormally high autofluorescence predated loss of visual acuity or visual field changes. Pattern electroreti nographic (PERG) findings were affected early in disease. There was high in trafamilial and interfamilial consistency of phenotype. Conclusion: These families demonstrate a striking conformity of symptoms an d signs. Clinical Relevance: In the codon 172 RDS mutation, unlike disease resulting from other RDS mutations, prediction of approximate age of onset and progr ession of visual deficit is possible. This should assist diagnosis and coun seling.