title: Hematological findings in Noonan syndrome.
abstract: OBJECTIVE
  Noonan syndrome is a multiple congenital anomaly syndrome, and bleeding diathesis is considered part of the clinical findings. The purpose of this study was to determine the frequency of hemostatic abnormalities in a group of Noonan syndrome patients.
  
  
  METHODS
  We studied 30 patients with clinical diagnosis of Noonan syndrome regarding their hemostatic status consisting of bleeding time, prothrombin time, activated partial thromboplastin time and thrombin time tests, a platelet count, and a quantitative determination of factor XI.
  
  
  RESULTS
  An abnormal laboratory result was observed in 9 patients (30%). Although coagulation-factor deficiencies, especially factor XI deficiency, were the most common hematological findings, we also observed abnormalities of platelet count and function in our screening.
  
  
  CONCLUSIONS
  Hemostatic abnormalities are found with some frequency in Noonan syndrome patients (30% in our sample). Therefore, we emphasize the importance of a more extensive hematological investigation in these patients, especially prior to an invasive procedure, which is required with some frequency in this disorder.
authors.affiliation: Genetics Clinic Unit of the Children's Institute, Brazil.
authors.forename: Débora R
authors.initials: DR
authors.lastname: Bertola
authors.forename: Jorge David A
authors.initials: JD
authors.lastname: Carneiro
authors.forename: Elbio Antônio
authors.initials: EA
authors.lastname: D'Amico
authors.forename: Chong A
authors.initials: CA
authors.lastname: Kim
authors.forename: Lilian Maria José
authors.initials: LM
authors.lastname: Albano
authors.forename: Sofia M M
authors.initials: SM
authors.lastname: Sugayama
authors.forename: Claudette H
authors.initials: CH
authors.lastname: Gonzalez
mesh_terms: D000293:Adolescent; D000328:Adult; D001778:Blood Coagulation Disorders / Q000097:blood* / Q000150:complications; D002648:Child; D002675:Child, Preschool; D005173:Factor XI Deficiency / Q000150:complications; D005260:Female; D006474:Hemorrhagic Disorders / Q000209:etiology; D006801:Humans; D007223:Infant; D008297:Male; D009634:Noonan Syndrome / Q000097:blood* / Q000150:complications