COVID-19 patients more frequently had FV Leiden heterozygosity (p = 0.046), the ACE D/D genotype (p = 0.022), and the PAI 4G/4G genotype (p = 0.008) In the group of our 19 healthy controls, no patients with V Leiden mutations were identified (p = 0.047), 8 out of 19 showed the ACE I/D genotype (p = 0.008), 16 out of 19 controls showed the PAI-1-675 4G/5G genotype (p = 0.008), and no statistically significant differences were found for the other gene (Table 2). Here, SERPINE1 is linked to COVID-19.