Bleeding phenotype and hemostatic evaluation by thrombin generation in children with Noonan syndrome: A prospective study

Assaf A. Barg, Yonatan Yeshayahu, Einat Avishai, Ivan Budnik, Omri Cohen, Tami Brutman-Barazani, Rima Dardik, Annick Raas-Rothschild, Sarina Levy-Mendelovich, Tami Livnat, Orit Pinhas-Hamiel, Gili Kenet

Research output: Contribution to journalArticlepeer-review


Background: This study aimed to evaluate the bleeding phenotype and to conduct a comprehensive hemostatic evaluation in individuals with Noonan syndrome (NS), a dominantly inherited disorder caused by pathogenic variants in genes associated with the Ras/MAPK signaling pathway. Methods: Children with a genetically confirmed diagnosis of NS underwent clinical evaluation, routine laboratory tests, platelet function testing, and thrombin generation (TG) assessment. Results: The study included 24 children. The most frequently reported bleeding symptoms were easy bruising and epistaxis, while bleeding complications were observed in 15% of surgical procedures. Various hemostatic abnormalities were identified, including platelet dysfunction, von Willebrand disease, and clotting factor deficiencies. Abnormal platelet function was observed in 50% of the patients, and significantly lower TG parameters were found compared to controls. However, no significant correlation was observed between bleeding symptoms and TG results. Conclusions: The study suggests that the bleeding diathesis in NS is multifactorial, involving both platelet dysfunction and deficiencies of plasma coagulation factors. The potential role of TG assay as an ancillary tool for predicting bleeding tendencies in individuals with NS undergoing surgery warrants further investigation.

Original languageEnglish
Article numbere30761
JournalPediatric Blood and Cancer
Issue number2
StatePublished - Feb 2024
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2023 Wiley Periodicals LLC.


Gili Kenet is a consultant for ASC therapeutics, Bayer, Biomarine, Novonordisk, Pfizer, Roche, Sanofi‐Genzyme, Sobi, Takeda, and Uniquore. Grants/research support/funding from BSF, Opko Biologics, Pfizer, Roche, and Shire. Honoraria from: Bayer, BioMarin, BPL, CSL, Pfizer, Novonordisk, Roche, Sanofi‐Genzyme, Sobi, Spark, Takeda, and Uniquore, and is a member on the advisory board of PedNet Foundation. Omri Cohen receives research grant from Pfizer and acts as a constultant for PlasFree. Assaf Barg receives honoraria for lectures from ROCHE. Sarina‐Levy Mendelovich receives grants from Pfizer and NovoNordisk, and honoraria from Pfizer.

FundersFunder number
Novo Nordisk


    • Noonan syndrome
    • bleeding
    • light transmission aggregometry
    • surgery
    • thrombin generation


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