Paediatric myelodysplastic syndromes and juvenile myelomonocytic leukaemia: molecular classification and treatment options.

Myelodysplastic syndromes (MDS) and the mixed myelodysplastic/myeloproliferative disorder juvenile myelomonocytic leukaemia (JMML) are rare haematopoietic stem cell diseases in children. While MDS-initiating events remain largely obscure, a growing body of clinical, genetic and laboratory evidence suggests that JMML is, at least in part, caused by aberrant signal transduction resulting from mutations of components of the RAS signalling pathway. To date, haematopoietic stem cell transplantation cures more than half of children diagnosed with MDS or JMML. Research on genetic conditions predisposing to MDS in young age, such as inherited syndromes with bone marrow failure, may present important insights into MDS pathogenesis.