Concomitant constitutive LNK and NFE2 mutation with loss of sum9oylation in a case of hereditary thrombocythemia

The vast majority of patients with myeloproliferative neoplasms (MPN), polycythemia vera, essential thrombocythemia (ET), and primary myelofibrosis, acquire driver mutations in the JAK2, MPL or CALR gene. Clustering of MPN is seen in select families, but in most pedigrees the MPN-predisposing change has not been determined and affected individuals somatically acquire one of the three above mentioned driver mutations. In contrast, a small number of individuals with hereditary thrombocythemia (HT) carry constitutive alterations, for example in the TPO or the LNK (SH2B3) gene.1–4 Acquired mutations in LNK, a negative regulator of JAK2 signaling, rarely occur in both sporadic and familial MPN cases.1,2 In the latter, they do not segregate with disease phenotype and diseased individuals acquire a concomitant MPN driver mutation.2 It, therefore, appears unlikely that mutant LNK acts as a driver in MPN