JAK2 and myeloproliferative disorder: Therefore, the JAK2 46/1 haplotype confers predisposition to the development of myeloproliferative neoplasms associated with the JAK2 V617F mutation (OR = 3.7; 95% CI = 3.1–4.3) and provides a conceptual framework in which a constitutional genetic component is associated with a substantial increase in the risk of acquiring a specific somatic mutation14.