However, patients with genetic abnormalities in the complement system tend to only develop overt disease in one organ (such as AMD, C3 glomerulopathy, or atypical haemolytic uraemic syndrome), even in the presence of rare, pathogenic variants or haploinsufficiency of FH and FI [81,220,221,222,223]. This evidence concerns the gene CFI and age-related macular degeneration.