Furthermore, they also display a higher median serum CD34+ cells (14/mcL vs. 6.8/mcL) and LDH level (369 U/L vs. 249 U/L), and include a higher number of patients with BM fibrosis grade ≥2 (53% vs. 21%), splenomegaly (50% vs. 34%) and CALR mutations (32% vs. 10%). The gene discussed is CALR; the disease is Splenomegaly.