Adult-onset foveomacular vitelliform dystrophy (AFVD) shares phenotypic similarities with age-related macular degeneration (AMD). The genetic factors associated with AFVD are unknown in >80% of cases. This study evaluated the association of known AMD genetic risk variants with AFVD and compared systemic complement activation in these conditions.
Clinical, imaging, and genetic data were collected from 50 patients with AFVD (men/women = 25/25, mean age ± SD 73 ± 10 years), 917 patients with AMD (men/women = 377/540, mean age ± SD 77 ± 9 years), and 432 unaffected healthy controls (men/women = 202/230, mean age ± SD 71 ± 8 years). Genotyping focused on 52 single nucleotide polymorphisms (SNPs) linked to AMD. Weighted genetic risk scores (GRS) for 19 complement system associated variants, 7 lipid metabolism associated variants, the remaining 26 variants (other pathways GRS), and for all 52 variants (global score) were derived and correlated with phenotype.
Of the 52 SNPs evaluated, CFH (rs570618) and C2/CFB/SKIV2L (rs116503776 and rs114254831) were associated with AFVD compared with healthy controls (odds ratio [OR] = 2.73, 95% confidence interval [CI] = 1.32-5.73, P = 0.01; OR = 0.31, 95% CI = 0.14-0.71, P = 0.0036; and OR = 0.41, 95% CI = 0.22-0.74, P = 0.0025, respectively). MIR6130/RORB (rs10781182) was negatively associated with AFVD compared with the healthy controls (OR = 0.13, CI = 0.06-0.25, P < 0.0001) and AMD (OR = 0.19, CI = 0.10-0.34, P < 0.0001). Regression analysis showed complement GRS was positively associated with AFVD compared with controls (OR = 1.42, 95% CI = 1.04-1.95, P = 0.03), whereas the other pathways' GRS was negatively associated (OR = 0.46, 95% CI = 0.21-0.98, P = 0.04). AMD was positively associated with the complement score, global score, and ARMS2/HTRA1 compared with controls.
Non-monogenic AFVD is associated with AMD risk alleles in the complement cascade, but not in other pathways. Further research is needed to explore complement inhibition for AFVD.