In a recent pediatric study, EPC counts (CD34+KDR+VEGFR2+) were reduced concordantly with impaired endothelial function in prepubertal children with OSA compared to control subjects [32], and the difference EPC density appeared to account at least partly to the variation in endothelial functional phenotypes in those with OSA. The gene discussed is KDR; the disease is obstructive sleep apnea syndrome.