Platelet changes and bleeding symptoms in children, adolescents, and adults with 22q11.2 deletion syndrome.

Abstract

The deletion region of 22q11.2 deletion syndrome (22q11.2DS) contains a gene encoding glycoprotein Ibβ (GPIbβ), which is required to express the GPIb/IX/V complex on the platelet surface. Therefore, patients with 22q11.2DS may have congenital platelet disorders. However, information is limited on platelets and bleeding symptoms. In this study, we investigated clinical information, including bleeding symptoms, platelet counts, and GPIb expression levels in children and adolescents/adults with 22q11.2DS. Thirty-two patients with 22q11.2DS were enrolled in a prospective cohort study between 2022 and 2023 at outpatient clinics within our institute. The median platelet counts in adolescents/adults with 22q11.2DS were significantly lower than those in children (p<.0001). A gradual decrease was found along with increasing age (p=.0006). Values of median GPIb expression on platelet surfaces (66% in children and 70% in adolescents/adults) were significantly lower than those in healthy controls (p<.0001 and p=.0002). Bleeding symptoms included surgery-related bleeding (52%), purpura (31%), and epistaxis (22%); most of them were minor. The median International Society on Thrombosis and Hemostasis bleeding assessment tool score was not significantly different between children and adolescents/adults (p=.2311). Although there was an age-related decrease in platelet count and a disease-related decrease in GPIb expression, no difference in bleeding symptoms was found between children and adolescents/adults. 22q11.2DS overall had minor bleeding symptoms in daily life, and the disease had little effect on spontaneous bleeding. However, some patients had major bleeding events; further accumulation of data on hemostasis during surgery and trauma is required.