Severe Clinical Course in a Patient with Congenital Amegakaryocytic Thrombocytopenia Due to a Missense Mutation of the c-MPL Gene

Abstract

Congenital amegakaryocytic thrombocytopenia (CAMT) generally begins at birth with severe thrombocytopenia and progresses to pancytopenia. It is caused by mutations in the thrombopoietin receptor gene, the myeloproliferative leukemia virus oncogene (c-MPL). The association between CAMT and c-MPL mutation type has been reported in the literature. Patients with CAMT have been categorized according to their clinical symptoms caused by different mutations. Missense mutations of c-MPL have been classified as type II and these patients have delayed onset of bone marrow failure compared to type I patients. Here we present a girl with severe clinical course of CAMT II having a missense mutation in exon 4 of the c-MPL gene who was admitted to our hospital with intracranial hemorrhage during the newborn period.

Figure 1. Progression of bone marrow failure in a child with CAMT. A, B, C- Bone marrow aspiration performed at 2 years of age showed no megakaryocytes in a cellular particle with erythroid and myeloid precursors without dysplasia (100x, 1000x, 1000x, respectively). D, E, F- Bone marrow aspirate showed very hypocellular results with few lymphocytes at 2.5 years of age (100x, 100x, 1000x, respectively).