title: Portal vein thrombosis in children and adolescents: the low prevalence of hereditary thrombophilic disorders.
abstract: OBJECTIVE
  The aim of this study was to determine the frequency of thrombophilic disorders in children and adolescents with portal vein thrombosis (PVT) as well as assessing the hereditary character of this disorder.
  
  
  METHODS
  A 2-year prospective study was carried out in pediatric PVT patients (n = 14), their parents (n = 25), and an age-matched control group free of liver disease (n = 28). The presence of PVT was assessed by means of Doppler ultrasound scan or angiography. None of the PVT patients presented biochemical or histologic signs of liver disease.
  
  
  RESULTS
  The frequency in PVT patients of protein C (PC), protein S (PS) and antithrombin (AT) deficiency was 42.9% (P <.05 v controls), 21.4% (P >.05) and 7.1% (P >.05), respectively. None of the controls or parents of PVT patients presented hereditary PC, PS, or AT deficiency. One PVT patient and one control (P =.999) presented prothrombin G20210A mutation. Homozygous methylenetetrahydrofolate reductase C677T genotype was observed in 3 of 14 (21.4%) PVT patients and in 5 of 28 (17.9%; P =.356) controls. None of these patients presented factor V G1691A mutation.
  
  
  CONCLUSIONS
  PC deficiency was frequent in pediatric PVT patients and does not seem to be an inherited condition. The hereditary prothrombotic disorders do not seem to play a vital role in thrombosis in children and adolescents with PVT.
authors.affiliation: Division of Pediatric Gastroenterology and Hematology Unit, Clinical Pathology Service, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil.
authors.forename: Raquel B
authors.initials: RB
authors.lastname: Pinto
authors.forename: Themis R
authors.initials: TR
authors.lastname: Silveira
authors.forename: Eliane
authors.initials: E
authors.lastname: Bandinelli
authors.forename: Liane
authors.initials: L
authors.lastname: Röhsig
mesh_terms: D000293:Adolescent; D020152:Antithrombin III Deficiency / Q000453:epidemiology; D001938:Brazil / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D005165:Factor V / Q000235:genetics; D005260:Female; D006471:Gastrointestinal Hemorrhage / Q000209:etiology; D006801:Humans; D007223:Infant; D008297:Male; D042965:Methylenetetrahydrofolate Reductase (NADPH2) / Q000172:deficiency / Q000235:genetics; D009154:Mutation; D011169:Portal Vein; D015995:Prevalence; D011446:Prospective Studies; D020151:Protein C Deficiency / Q000453:epidemiology; D018455:Protein S Deficiency / Q000453:epidemiology; D011516:Prothrombin / Q000235:genetics; D011859:Radiography; D013163:Splenomegaly / Q000209:etiology; D019851:Thrombophilia / Q000150:complications / Q000453:epidemiology* / Q000235:genetics; D014424:Turner Syndrome / Q000150:complications; D014463:Ultrasonography; D020246:Venous Thrombosis / Q000150:complications / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000209:etiology
chemical_list: C095381:factor V Leiden; D005165:Factor V; D011516:Prothrombin; D042965:Methylenetetrahydrofolate Reductase (NADPH2)