In hematological conditions somatic SH2B3 variants have been described in 5–7% of patients with myeloproliferative neoplasms (MPN) and, at lower frequency, in juvenile myelomonocytic leukemia (JMML) [9, 10], high-risk B- and early T-cell precursor acute lymphoblastic leukemia (ALL) [4]. This evidence concerns the gene SH2B3 and juvenile myelomonocytic leukemia.