FACTOR-V LEIDEN IS NOT COMMON IN CHILDREN WITH PORTAL-VEIN THROMBOSIS

Portal vein thrombosis (PVT) is a rare condition affecting both childr en and adults, and occurs in association with a wide variety of clinic al situations. On the other hand, the development of PVT in patients u nder these situations indicates that other contributing factors could be envolved. Recently a missense mutation in the factor V gene (1691G- ->A), known as factor V Leiden, has been identified and results in abn ormal factor V product, resistant to proteolytic inactivation by activ ated protein C and thus predisposes to thrombosis. This study was carr ied out to verify if children with PVT have an increase in frequency o f factor V Leiden. Allele-specific restriction analysis and single str and conformational polymorphism (SSCP) were used to test for factor V Leiden in 20 children with PVT and 64 normal children. None of the PVT children were heterozygous or homozygous for the factor V Leiden, and one control child was heterozygous. This study demonstrates that fact or V Leiden is not common in children with PVT, and is not a prerequis ite for this thrombotic event.