Driver mutation status in the population of children, adolescents, and young adults. (A) Driver mutation status depending on MPN subtype in the global population. (B) Driver mutations observed in the ET population depending on age. (C) JAK2V617F allele burden at diagnosis of MPN. 3NEG, triple negative; CALR, calreticulin; JAK2, just another kinase 2; Others, MPL or unknown.