PROC and deep vein thrombosis: PC deficiencies are common among Asian patients with inherited thrombophilia.[2,3] Hereditary PC deficiency results from mutations in the PROC gene and the severity of symptoms is determined by the presence of homozygous or heterozygous mutations.[4] Homozygous patients present with more severe symptoms including pulmonary embolism, disseminated intravascular coagulation, and deep vein thrombosis in the neonatal period.