PROTEIN-C, PROTEIN-S AND ANTITHROMBIN-III IN CHILDREN WITH PORTAL-VEIN OBSTRUCTION

Background/Aims: Portal vein obstruction is the most common single cau se of portal hypertension in children and its cause is unknown in most instances. The aim of the present study nas to evaluate the incidence of protein C, protein S and antithrombin III deficiencies and to scre en for possible genetic deficiencies of these proteins. Methods: A pro spective study was undertaken in 20 consecutive children with portal v ein obstruction, their parents and 20 matched healthy children. Result s: Children with portal vein obstruction displayed a reduction in prot ein C (p<0.05), protein S (p<0.0001), and antithrombin III (p<0.001) a ctivities as compared with controls. Protein C and protein S activitie s were below 60% in nine and eleven of the children with portal rein o bstruction, respectively, and antithrombin III activities were below o r equal to 85% in ten of them. Repented assay of protein C activity in seven children following a surgical portosystemic shunt showed a decr ease as compared with preoperative values. Protein C, protein S and an tithrombin III were normal in all parents, except two mothers in whom the levels of protein S activity and protein S antigen were found to b e either below or at the lower limit of the normal range. Conclusions: These results indicate that protein C, protein S and/or antithrombin III deficiencies are frequently found in children with portal vein obs truction but are not likely to be of genetic origin in most cases.