Transient abnormal myelopoiesis in a phenotypically normal newborn with polyclonal trisomy 21

• DOI: 10.1007/s12185-014-1584-0
• Publication Date: 2014-04-25T07:34:15Z
• Authors: Francesco Corazza; Annalisa Astolfi; Virginia Libri; Monica Franzoni; Salvatore Serravalle; Rosina Alessandroni; Fraia Melchionda; Andrea Pession
• Keywords: Trisomy; Myelopoiesis; Polyclonal antibodies; Trisomy 8

We report a rare case of transient abnormal myelopoiesis (TAM) in a phenotypically normal neonate. The presence of a palpable hepatomegaly prompted in-depth laboratory tests, which revealed the presence of severe hyperleukocytosis, with blast cells present in a peripheral blood smear. Although no signs of Down syndrome were present, we suspected TAM. Further analysis identified a mutation in GATA1 along with the unique finding of two different trisomic cell lines, detected upon karyotyping; one with trisomy 21 only, and one with trisomies 21 and 22, which was present in a subpopulation of peripheral blood cells. These genetic abnormalities disappeared by the age of 6 months. The presence of two different trisomic clones may be an evidence of the polyclonal nature of TAM in this patient.