PT - JOURNAL ARTICLE AU - Mays Talib AU - Caroline Van Cauwenbergh AU - Julie De Zaeytijd AU - David Van Wynsberghe AU - Elfride De Baere AU - Camiel J F Boon AU - Bart Peter Leroy TI - <em>CRB1</em>-associated retinal dystrophies in a Belgian cohort: genetic characteristics and long-term clinical follow-up AID - 10.1136/bjophthalmol-2020-316781 DP - 2022 May 01 TA - British Journal of Ophthalmology PG - 696--704 VI - 106 IP - 5 4099 - http://bjo.bmj.com/content/106/5/696.short 4100 - http://bjo.bmj.com/content/106/5/696.full SO - Br J Ophthalmol2022 May 01; 106 AB - Aim To investigate the natural history in a Belgian cohort of CRB1-associated retinal dystrophies.Methods An in-depth retrospective study focusing on visual function and retinal structure.Results Forty patients from 35 families were included (ages: 2.5–80.1 years). In patients with a follow-up of &gt;1 year (63%), the mean follow-up time was 12.0 years (range: 2.3–29.2 years). Based on the patient history, symptoms and/or electroretinography, 22 patients (55%) were diagnosed with retinitis pigmentosa (RP), 15 (38%) with Leber congenital amaurosis (LCA) and 3 (8%) with macular dystrophy (MD), the latter being associated with the p.(Ile167_Gly169del) mutation (in compound heterozygosity). MD later developed into a rod-cone dystrophy in one patient. Blindness at initial presentation was seen in the first decade of life in LCA, and in the fifth decade of life in RP. Eventually, 28 patients (70%) reached visual acuity-based blindness (&lt;0.05). Visual field-based blindness (&lt;10°) was documented in 17/25 patients (68%). Five patients (13%) developed Coats-like exudative vasculopathy. Intermediate/posterior uveitis was found in three patients (8%). Cystoid maculopathy was common in RP (9/21; 43%) and MD (3/3; 100%). Macular involvement, varying from retinal pigment epithelium alterations to complete outer retinal atrophy, was observed in all patients.Conclusion Bi-allelic CRB1 mutations result in a range of progressive retinal disorders, most of which are generalised, with characteristically early macular involvement. Visual function and retinal structure analysis indicates a window for potential intervention with gene therapy before the fourth decade of life in RP and the first decade in LCA.Data are available upon reasonable request.