The S505A thrombopoietin receptor mutation in childhood hereditary thrombocytosis and essential thrombocythemia is S505N: single letter amino acid code matters.

Dear Editor, Myeloproliferative neoplasms (MPNs) are rare diseases in children [1] when compared to adults [2]. Targeted sequencing revealed differences in the mutational landscape of pediatric and adult MPNs [1]. Children exhibit a lower frequency of mutations in the MPN driver genes JAK2, MPL, and CALR, and a much higher proportion of children exhibit no mutation among the 104 classically involved genes; these children exhibiting a trend towards essential thrombocythemia (ET) [1]. We were surprised to read about an activating thrombopoietin receptor (TpoR/Mpl) S505A transmembrane domain (TM) mutation in childhood hereditary thrombocytosis (HT) and ET [3–5]. [...