Congenital amegakaryocytic thrombocytopenia (CAMT) is caused by the loss of thrombopoietin receptor-mediated (MPL-mediated) signaling, which causes severe pancytopenia leading to bone marrow failure with onset of thrombocytopenia and anemia prior to leukopenia.
Median mutation levels in pretreatment ET samples were significantly higher for MPL-mutated cases (60%) than for JAK2-mutated cases (24%; P=0.01), as was presentation with anemia.
When compared with MPL wild-type patients, irrespective of JAK2(V617F) status, those with MPL(W515L/K), were more frequently female, were older (61 years vs. 57 years; P = 0.02), presented with more severe anaemia (haemoglobin, 101 g/l vs. 121 g/l; P = 0.002) and were more likely to require regular transfusional support (P = 0.012).