RESISTANCE TO ACTIVATED PROTEIN-C (APCR) IN CHILDREN WITH VENOUS OR ARTERIAL THROMBOEMBOLISM

Resistance to activated protein C (APCR), in the majority of cases due to the point mutation Arg 506 Gin of the factor V gene, has emerged a s the most important hereditary cause of venous thromboembolism. Using an activated thromboplastin time (aPTT) based method in the presence of APC together with a DNA technique based on the polymerase chain rea ction, we investigated 37 children with venous (V: n=19) or arterial ( A: n=18) thromboembolism and matched healthy controls for the presence mutation, In the control group 10 children were detected to be hetero zygous for the factor V Leiden mutation, indicating a prevalence of 5. 1%. 10/19 children (52%) with venous thrombosis and 7/18 (38%) patient s with arterial thromboembolism showed the common factor V gene mutati on. Additional inherited coagulation disorders were found in 1/10 (V: 10%) and 2/7 (A: 28%) APC-resistant patients, Inherited coagulation di sorders without APCR were diagnosed in 3/9 (V: 33%) and 2/11 (A: 18%) children, Furthermore, we diagnosed exogenous risk factors in 6/10 (V: 60%) and 2/7 (A: 28%) children with thrombosis and APCR. These data a re evidence that APCR combined with exogenous reasons may play an impo rtant role in the early manifestation of thromboembolism during infanc y and childhood.