Cytogenetic and molecular genetic aspects of childhood myeloproliferative/myelodysplastic disorders.

Of the myeloproliferative/myelodysplastic disorders (MPD/MDS) that occur in childhood most, regarding the cytogenetic and molecular genetic basis, is known about the two purely paediatric disorders: juvenile myelomonocytic leukaemia (JMML) and transient myeloproliferative disorder (TMD). Although much has been published about these two disorders, their aetiology is by no means fully established. It would appear, however, that in this paediatric subset of MPDs a stage/developmentally specific vulnerability for proliferation and transformation exists. The study of the molecular basis of many other MPD-like syndromes that also occur in childhood, has been greatly accelerated by the identification of rare, but recurring, cytogenetic abnormalities involving 8p11 and 5q31-33. Good collaborative studies could result in similar progress being made in the understanding of JMML and TMD.