Among WD-heterozygotes, MTHFR 677 stratification was less evident (WD/CC 6.5 ± 4.5, WD/CT 6.6 ± 4.6, and WD/TT 5.9 ± 3.9 years), virtually null among WW-homozygotes (WW/CC 5.5 ± 3.6, WW/CT 5.1 ± 4.3, and WW/TT 4.7 ± 2.1 years). This evidence concerns the gene MTHFR and Wilson disease.