Individuals with one allele with a histidine substitution for tyrosine in position 402 of the CFH gene (CFH Y402H) on chromosome 1 show a 1.5-to-3-fold increase in risk of developing AMD if heterozygous and up to a tenfold increase in risk if homozygous18,19,21,23–25. This evidence concerns the gene CFH and age-related macular degeneration.