Effect size analysis using Cohen’s d (Table 2) revealed large differences between thrombophilia and control groups for several genetic mutations, including PAI-1 4G/4G (d = 1.91), MTHFR C677T (d = 1.85), EPCR (d = 1.06), and Factor V Leiden (d = 0.93), suggesting strong associations with thrombophilic status. This evidence concerns the gene MTHFR and Rare hereditary thrombophilia.