Transient myeloproliferative disorder with partial trisomy 21

Myeloid malignancy with Down syndrome (ML-DS) is estimated to have a step-wise leukemogenesis including GATA1 mutation. Trisomy 21 is essential for ML-DS; however, we do not know exactly which gene or genes located on chromosome 21 are necessary for the ML-DS. We report a female infant with transient myeloproliferative disorder (TMD) and partial trisomy 21. SNP array analysis showed 10 Mb amplification of 21q22.12-21q22.3, which included DYRK1A, ERG, and ETS but not the RUNX1 gene. With two other reported TMD cases having partial trisomy 21, DYRK1A, ERG, and ETS were the most likely genes involved in collaboration with the GATA1 mutation.