Clinical spectrum, genetic associations and management outcomes of Coats-like exudative retinal vasculopathy in autosomal recessive retinitis pigmentosa

Background: Coats-like retinal vasculopathy in retinitis pigmentosa (RP) is rare. This study describes its clinical spectrum, management outcomes and genetic associations in patients with autosomal recessive RP (arRP). Materials and methods: Retrospective review of ophthalmic, multimodal imaging, genetic findings and treatment outcomes of arRP patients who developed Coats-like features. Identification of patients included searching a retinal dystrophy registry of 798 patients. Results: Ten eyes of six patients with arRP (4 males, 2 females, mean age 33 years) demonstrated Coats-like features, namely inferotemporal peripheral retinal telangiectasis combined with unilateral inferotemporal vasoproliferative tumor (VPT) in 4 eyes. Exudative retinal detachment (ERD) developed in five eyes of which four had VPT. Ablation of the vasculopathy using retinal laser photocoagulation and/or cryotherapy in eight eyes, allowed ERD and/or lipid exudation to decrease in seven eyes despite incomplete vasculopathy regression. Additional intravitreal triamcinolone acetonide injection in one eye failed to regress the ERD and associated VPT. Observation in one eye caused increased exudation. Six mutations, including three novel mutations, were found in CRB1, CNGB1, RPGR, and TULP1. Conclusions: Coats-like features in arRP range from retinal telangiectasis to VPTs with extensive ERD and occur predominantly in the inferotemporal retinal periphery. In addition to their classic association with CRB1 mutations, other genes are implicated. To the best of our knowledge, this is the first report describing CNGB1 mutations in Coats-like RP. Awareness of the vasculopathy spectrum is important, and timely ablation of the vasculopathy with long-term monitoring is recommended to prevent additional visual loss in RP patients.