Platelet Dysfunction in Noonan and 22q11.2 Deletion Syndromes in Childhood

Thrombosis and Haemostasis
Anna Ruiz-LlobetRubén Berrueco

Abstract

An underlying thrombocytopathy seems to be responsible for hemorrhagic symptoms in patients diagnosed with 22q11.2 deletion syndrome (22q11DS) or Noonan syndrome (NS). In 22q11DS, it is explained by a defect in the membrane glycoprotein (GP) complex Ib-V-IX. The cause of thrombocytopathy in NS remains unclear. The objective is to study the incidence of thrombocytopathy in pediatric patients diagnosed with 22q11DS or NS assessing the utility of ISTH-BAT questionnaire and laboratory techniques. Prospective study between March and December 2018 in children (2-18 years old) diagnosed with 22q11DS or NS. Hemorrhagic symptoms using ISTH-BAT score, total cell blood count, platelet indices, PFA-200 closure times, and platelet aggregation were evaluated in all patients and membrane GP expression in 22q11DS patients. Nearly 70% of NS patients (n = 22) had a platelet aggregation defect without thrombocytopenia. A defect of platelet aggregation with adenosine diphosphate (ADP) and epinephrine was the most frequent pattern. A statistically significant inverse correlation between closure times and aggregation with arachidonic acid (p = 0.049, p = 0.043) and epinephrine (p = 0.021, p = 0.035), and ADP (p = 0.117, p = 0.05) was found. Total 5 ...Continue Reading

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22q11 Deletion Syndrome

22q11.2 deletion syndrome, also known as DiGeorge syndrome, is a congenital disorder caused by a partial deletion of chromosome 22. Symptoms include heart defects, poor immune system function, a cleft palate, complications related to low levels of calcium in the blood, and delayed development. Discover the latest research on this disease here.