Expanding the ocular and genetic spectrum of FLVCR1-associated disease in a Chinese cohort.

backgroundBiallelic FLVCR1 variants have been linked to a phenotypic spectrum ranging from isolated autosomal recessive retinitis pigmentosa (RP) to syndromic posterior column ataxia with retinitis pigmentosa (PCARP), yet detailed phenotypic characterization remains limited, particularly in Chinese patients. PURPOSE: To delineate the ocular and extraocular phenotype of FLVCR1-associated disease and to expand its mutational spectrum.

methodsWe retrospectively reviewed five affected individuals with biallelic FLVCR1 variants confirmed by whole-exome sequencing (WES) and Sanger segregation analysis, and performed comprehensive ophthalmic assessments, including colour fundus photography, fundus autofluorescence (FAF), optical coherence tomography (OCT), perimetry, and full-field electroretinography (ffERG).

resultsFLVCR1-associated disease presented as early-onset severe retinal degeneration with heterogeneous neurological involvement. OCT consistently demonstrated outer retinal thinning with ellipsoid-zone attenuation, and FAF revealed characteristic abnormalities. Cone and rod function on ffERG could be severely impaired within the first decade of life, and high myopia was a recurrent accompanying feature. Neurological manifestations could be subtle or absent at initial presentation, with gait instability and neuropathic features emerging during longitudinal follow-up. We identified two previously unreported FLVCR1 variants, c.734A > G (p.Asn245Ser) and c.1024 + 1G > T.

conclusionsFLVCR1-associated disease can present as early-onset severe retinal degeneration (EOSRD), together with neurological involvement that may evolve over time. These findings refine phenotypic delineation, support multidisciplinary surveillance involving ophthalmology and neurology, and expand the known mutational spectrum of this rare disorder.