Morrell Ruth, Langabeer Stephen E, Smyth Liam, Perera Meegahage, Crotty Gerard
Department of Haematology, Midland Regional Hospital, Tullamore, Ireland.
Case Rep Hematol. 2013;2013:729327. doi: 10.1155/2013/729327. Epub 2013 Jul 18.
Mutations of MPL are present in a significant proportion of patients with the myeloproliferative neoplasms (MPN), primary myelofibrosis (PMF), and essential thrombocythaemia (ET). The most frequent of these mutations, W515L and W515K, occur in exon 10 of MPL, which encodes the receptor for thrombopoietin. Another exon 10 mutation, MPL S505N, has been shown to be a founder mutation in several pedigrees with familial thrombocythaemia where it is associated with a high thrombotic risk, splenomegaly and progression to bone marrow fibrosis. Rare cases of sporadic, nonfamilial, MPL S505N MPN have been documented, but the presenting laboratory and clinical features have not been described in detail. The diagnosis and clinical course of a case of MPL S505N-positive MPN are presented with diagnostic features and treatment response resembling typical ET but with evidence of increasing bone marrow fibrosis. Further MPN cases possessing this genotype require reporting in order to ascertain whether any particular morphological or clinical features, if present, determine clinical course and aid the refinement of therapeutic options.
在相当一部分骨髓增殖性肿瘤（MPN）、原发性骨髓纤维化（PMF）和真性红细胞增多症（ET）患者中存在MPL突变。这些突变中最常见的W515L和W515K发生在MPL的第10外显子，该外显子编码血小板生成素受体。另一个第10外显子突变MPL S505N已被证明是几个家族性血小板增多症家系中的奠基者突变，在这些家系中它与高血栓形成风险、脾肿大以及进展为骨髓纤维化有关。散发性、非家族性MPL S505N MPN的罕见病例已有记录，但目前尚未详细描述其呈现的实验室和临床特征。本文报告了一例MPL S505N阳性MPN的诊断及临床过程，其诊断特征和治疗反应类似于典型ET，但有骨髓纤维化加重的证据。需要报告更多具有这种基因型的MPN病例，以确定是否存在任何特定的形态学或临床特征来决定临床过程并有助于优化治疗方案。
