PURPOSE: To determine the genetic background of sector retinitis pigmentosa (RP), natural history, in order to better inform patient counselling. DESIGN: Retrospective case series. METHODS: Review of clinical notes, retinal imaging including color fundus photography (CFP), fundus autofluorescence (FAF), and optical coherence tomography (OCT), electrophysiological assessment (ERG), and molecular genetic testing was performed in patients with sector RP from a single tertiary referral center. MAIN OUTCOME: Measures: Reporting demographic data, signs and symptoms, visual acuity, molecular genetics, ERG, FAF and OCT findings. RESULTS: Twenty-six molecularly confirmed patients from 23 different families were identified, harboring likely disease-causing variants in nine genes. The mode of inheritance was autosomal recessive (AR, n=6: USH1C, n=2; MYO7A, n=2; CDH3, n=1; EYS, n=1), X-linked (XL, n=4: PRPS1, n=1; RPGR, n=3), and autosomal dominant (AD, n=16: IMPDH1, n=3; RP1, n=3; RHO, n=10), with a mean age of disease onset of 38.5, 30.5 and 39.0 years respectively. Five of these genes have not previously been reported to cause sector RP (PRPS1, MYO7A, EYS, IMPDH1, and RP1). Inferior and nasal predilection was common across the different genotypes and patients tended to maintain good central vision. Progression on serial FAF was observed in RPGR, MYO7A, CDH23, EYS, IMPDH1, RP1 and RHO-associated sector RP. CONCLUSIONS: The genotypic spectrum of the disease is broader than previously reported. The provided longitudinal data will help to provide more accurate patient prognosis and counselling, as well as inform patients' potential participation in the increasing numbers of trials of novel therapeutics and access to future treatments
