Patients with Noonan Syndrome May Have One or More Bleeding Disorders

ASPHO 2016 (Minneapolis, May 11-14) Patients with Noonan syndrome (NS) may have one or more bleeding disorders according to a comprehensive review presented at the recent 2016 American Society of Pediatric Hematology Oncology annual meeting. Noonan syndrome is an inherited condition characterized by certain characteristic facial features, growth problems (short stature), congenital heart diseases (inherited abnormalities that affect the heart), bone abnormalities, delays in reaching normal developmental milestones, and bleeding problems. Bleeding problems have been reported in a high percentage of affected patients, and becomes evident often during childhood when surgery is needed for correction of congenital abnormalities. In follow-up to discussions with hematologists and pediatric endocrinologists, a comprehensive review was done of  to identify exactly which bleeding disorders were most common in people with Noonan Syndrome. There were 31 scientific articles identified including clinical trials and reports of one or more cases. The results showed that 9 of 10 patients with NS had some reported bleeding laboratory test abnormalities, but just under half (45%) had a specific diagnosis reported. The most common laboratory test abnormalities were prolonged clotting laboratory tests suggesting factor deficiency and tests related to abnormal platelet function. Interestingly, while ~ 4 in 5 patients had single factor deficiencies, von Willebrand Disease (VWD) or platelet disorders, ~1 in 5 had multiple bleeding disorders. Congenital factor 11 deficiency was most common followed by platelet abnormalities, factor 12 deficiency (not typically a bleeding disorder) and factor 8 deficiency. Factors 11 and 12 and factor 11 and 8 were the most common combined disorders. Because these patients can have different types of bleeding disorders or more than one, one of the conclusions was that it was very important to perform comprehensive testing for clotting factor deficiencies and platelet disorders in patients with NS early in childhood, especially in the pre-operative setting.