Particularly, a previous study demonstrated a larger Ca2+ release from the ER in cultured megakaryocytes of patients with MPN and type 1 CALR mutations than in patients carrying either the JAK2 mutation or type 2 CALR mutation, suggesting that phenotypic differences between type 1-like and type 2-like CALR mutations may be related to the greater loss of calcium-binding sites in patients with type 1-like mutation [6]. This evidence concerns the gene CALR and myeloproliferative disorder.