Abstract
Purpose :
To evaluate the presence of SAG mutations in a cohort of Texas patients with retinitis pigmentosa and to report on the phenotype.
Methods :
We investigated 79 patients in our database in whom a genetic cause has been identified for the phenotype of retinitis pigmentosa. We evaluated self identified ethnicity in thest patients. We evaluated the clinical phenotype of these patients including fundus appearance, visual acuity, and visual field.
Results :
Eight patients with SAG mutations were found in a cohort of 79 patients with retinitis pigmentosa. All patients were of Hispanic descent. The inheritance pattern was autosomal dominant in all patients. Six of the patients had the SAG c.440G>T, p.(Cys147Phe) mutation. The Snellen visual acuity of these patients was 20/20 or better in all patients. Two patients had other mutations in the SAG gene. These patients ranged in age from 23 to 63. Symptoms of nyctalopia, poor peripheral vision and difficulty with driving was reported in all patients. Visual field constriction was present in all patients. The two patients with other mutations in the SAG gene had poorer visual function than those with the SAG c.440G>T, p.(Cys147Phe) mutation. The clinical phenotype was typical of retinitis pigmentosa with notable RPE atrophy along the major arcade vessels and bone spicule type pigmentation in the midperiphery.
Conclusions :
SAG mutations are an important cause of autosomal dominant retinitis pigmentosa in Hispanic patients in south Texas. This confirms a similar observation in another cohort of patients with retinitis pigmentosa. The clinical phenotype is characteristic for retinitis pigmentosa with significant RPE atrophy along the major arcade vessels. Six of the eight patients had the SAG c.440G>T, p.(Cys147Phe) mutation in the SAG gene, consistent with a founder effect. Patients with this mutation in this cohort maintained functional visual function into the 7th decade of life. This mutation is an important target for future therapetic trials.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.