The median FI level was significantly lower in those individuals with AMD and a rare CFI variant (28.3 μg/mL) compared to those with AMD without a rare CFI variant (38.8 μg/mL, P = 0.004) or the control population with (41.7 μg/mL, P = 0.0085) or without (41.5 μg/mL, P < 0.0001) a rare CFI variant. The gene discussed is CFI; the disease is age-related macular degeneration.