title: Hemostatic abnormalities in Noonan syndrome.
abstract: BACKGROUND
  A bleeding diathesis is a common feature of Noonan syndrome, and various coagulation abnormalities have been reported. Platelet function has never been carefully investigated.
  
  
  METHODS
  The degree of bleeding diathesis in a cohort of patients with Noonan syndrome was evaluated by a validated bleeding score and investigated with coagulation and platelet function tests. If ratios of prothrombin time and/or activated partial thromboplastin time were prolonged, the activity of clotting factors was measured. Individuals with no history of bleeding formed the control group.
  
  
  RESULTS
  The study population included 39 patients and 28 controls. Bleeding score was ≥2 (ie, suggestive of a moderate bleeding diathesis) in 15 patients (38.5%) and ≥4 (ie, suggestive of a severe bleeding diathesis) in 7 (17.9%). Abnormal coagulation and/or platelet function tests were found in 14 patients with bleeding score ≥2 (93.3%) but also in 21 (87.5%) of those with bleeding score <2. The prothrombin time and activated partial thromboplastin time were prolonged in 18 patients (46%) and partial deficiency of factor VII, alone or in combination with the deficiency of other vitamin K-dependent factors, was the most frequent coagulation abnormality. Moreover, platelet aggregation and secretion were reduced in 29 of 35 patients (82.9%, P < .01 for all aggregating agents).
  
  
  CONCLUSIONS
  Nearly 40% of patients with the Noonan syndrome had a bleeding diathesis and >90% of them had platelet function and/or coagulation abnormalities. Results of these tests should be taken into account in the management of bleeding or invasive procedures in these patients.
authors.affiliation: Department of Internal Medicine and Medical Specialties, A. Bianchi Bonomi Hemophilia and Thrombosis Center, Milan, Italy;
authors.forename: Andrea
authors.initials: A
authors.lastname: Artoni
authors.affiliation: Pediatric Unit, San Gerardo Hospital, Monza, Italy; and.
authors.forename: Angelo
authors.initials: A
authors.lastname: Selicorni
authors.affiliation: Department of Internal Medicine and Medical Specialties, A. Bianchi Bonomi Hemophilia and Thrombosis Center, Milan, Italy;
authors.forename: Serena M
authors.initials: SM
authors.lastname: Passamonti
authors.affiliation: Department of Internal Medicine and Medical Specialties, A. Bianchi Bonomi Hemophilia and Thrombosis Center, Milan, Italy;
authors.forename: Anna
authors.initials: A
authors.lastname: Lecchi
authors.affiliation: Department of Internal Medicine and Medical Specialties, A. Bianchi Bonomi Hemophilia and Thrombosis Center, Milan, Italy;
authors.forename: Paolo
authors.initials: P
authors.lastname: Bucciarelli
authors.affiliation: Pediatric Clinic 1, Department of Pathophysiology and Transplantation, Fondazione IRCCS Ca' Granda-Ospedale Maggiore Policlinico, Milan, Italy.
authors.forename: Marta
authors.initials: M
authors.lastname: Cerutti
authors.affiliation: Pediatric Unit, San Gerardo Hospital, Monza, Italy; and.
authors.forename: Paola
authors.initials: P
authors.lastname: Cianci
authors.affiliation: Department of Internal Medicine and Medical Specialties, A. Bianchi Bonomi Hemophilia and Thrombosis Center, Milan, Italy;
authors.forename: Francesca
authors.initials: F
authors.lastname: Gianniello
authors.affiliation: Department of Internal Medicine and Medical Specialties, A. Bianchi Bonomi Hemophilia and Thrombosis Center, Milan, Italy; martin@policlinico.mi.it.
authors.forename: Ida
authors.initials: I
authors.lastname: Martinelli
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006474:Hemorrhagic Disorders / Q000097:blood* / Q000175:diagnosis*; D020141:Hemostatic Disorders / Q000097:blood* / Q000175:diagnosis*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D009634:Noonan Syndrome / Q000097:blood* / Q000175:diagnosis*; D010314:Partial Thromboplastin Time; D010974:Platelet Aggregation / Q000502:physiology; D010979:Platelet Function Tests; D011517:Prothrombin Time; D055815:Young Adult
keywords: Noonan syndrome; bleeding score; coagulation; platelets