C3 and peripheral arterial disease: Some genes are indicated as related with PAD, such as C3 (complement component 3) (Fehervari et al., 2014), PTGS2 (prostaglandin-endoperoxide synthase 2) (Flórez et al., 2009), SERPINE1 (Björck et al., 2013), S100A12 (Shiotsu et al., 2011), and TNF (Botti et al., 2012; Wozniak et al., 2012; Gardner et al., 2014).