A Novel ARL3 Gene Mutation Associated With Autosomal Dominant Retinal Degeneration
BRIEF DESCRIPTION
A mutation in the ADP ribosylation factor-like GTPase 3 (ARL3) gene can cause retinitis pigmentosa (RP), a disease that leads to vision loss. A missense variant in ARL3 can cause non-syndromic autosomal dominant RP. For example, the c. 269A > G (p. Tyr90Cys) variant has been found in two unrelated families. ARL3 is found in the photoreceptor cilium of the retina. It helps transport cargo complexes through the cilium, which contain proteins like rhodopsin kinase and transducin. ARL3 is regulated by retinitis pigmentosa 2 (RP2) and ARL13b. RP2 is a GTPase activating protein (GAP) for ARL3, while ARL13b is a GTP-exchange factor (GEF).
ARF1 and ARF3 are identical except for seven amino acid differences in their N-terminal and C-terminal regions, and previously they were thought to function and localize identically.
Symptoms of RP include difficulty adapting to dim light after being in bright light, difficulty seeing in dim light, and vision narrowing. Progression of these symptoms vary. While there's no cure for RP, there are ways to help with vision loss. These include low vision aids, rehabilitation programs, vitamins and supplements have been recommended but efficacy has been debated. Most people with RP don't completely lose their vision, but they may be considered legally blind due to limited peripheral vision.