Do MEFV genotypes shape retinal and choroidal microvascular involvement in familial Mediterranean fever?

PURPOSE: To evaluate retinal and choroidal microvascular alterations in patients with Familial Mediterranean Fever (FMF) and to investigate their associations with MEFV genotype and clinical phenotype using optical coherence tomography angiography (OCTA). METHODS: In this cross-sectional study, 130 FMF patients (260 eyes) and 120 age- and sex-matched healthy controls (240 eyes) underwent OCTA imaging. Patients were stratified according to MEFV genotype and clinical phenotype, including amyloidosis, arthritis, serositis, and erysipelas-like erythema. Vessel density parameters in the superficial and deep capillary plexus (SCP and DCP), foveal avascular zone (FAZ), retinal nerve fiber layer (RNFL), choriocapillaris flow area, and optic nerve head parameters were analyzed using linear mixed-effects models adjusted for age and sex. RESULTS: Compared with controls, FMF patients demonstrated significantly reduced DCP vessel density in the whole image, parafoveal, and perifoveal regions, whereas SCP, FAZ, RNFL, and optic nerve head parameters were comparable. Within the FMF cohort, age was the strongest predictor of reduced DCP vessel density and choriocapillaris flow. M694V carriage and amyloidosis were independently associated with lower parafoveal and perifoveal DCP vessel density. CONCLUSIONS: FMF is associated with selective deep retinal microvascular impairment, particularly in patients carrying the M694V mutation and in those with amyloidosis. OCTA-derived DCP parameters may serve as non-invasive biomarkers of systemic microvascular involvement in FMF.