MTHFR and peripheral arterial disease: The association between PAD and MTHFR variants has been studied in literature with controversial results; the Linz Peripheral Arterial Disease (LIPAD) study did not correlate MTHFR 677C>T with PAD,18 while a meta-analysis of nine appropriate studies showed that homozygosity for the T allele was associated with an increased risk of PAD.19