C4A and age-related macular degeneration: The top rare variant (p.V1207A, MAF = 0.0081 in 1,000 genomes and MAF = 0.0082 in ExAC) was a risk variant for AMD in our analyses and independent of reported known AMD risk variants in the CFB/C2 locus or any other variants that were associated with C4A copy number (r2 > 0.7).