In the subjects with JAK2V617F, the TT genotype was associated with more severe disease at diagnosis, i.e., lower platelet concentration, higher plasma LDH concentration, splenomegaly, increased blood concentration of CD34-positive cells, lower serum cholesterol concentration, more inflammation evidenced by higher plasma hs-CRP concentration, and an increased risk of developing thrombocytopenia. The gene discussed is CD34; the disease is Thrombocytopenia.