PROS1 and antiphospholipid syndrome: The published case studies highlight the following causes of portal vein thrombosis: sticky platelet syndrome type 2, thalassaemia [15], congenital hepatic fibrosis [16], omphalitis [17], hepatic haemangioma, protein S deficiency [18], hepatocellular carcinoma, thrombophilia [19], antiphospholipid syndrome [20], and COVID-19 infection [21].