Transient myeloproliferative disorder as the presenting feature for mosaic trisomy 21

Abstract

Trisomy 21 is a common congenital disorder with well documented clinical manifestations, including an increased risk for transient myeloproliferative disorder as a neonate and leukemia in childhood and adolescence. Children with mosaic trisomy 21 can have a similar risk for hematological malignancies. We present a non-dysmorphic neonate, with negative noninvasive prenatal screening of maternal blood for trisomy 21, who came to medical attention because of ruddy skin. He was found to have mild polycythemia, thrombocytopenia and developed peripheral blasts. His clinical presentation was concerning for transient myeloproliferative disorder, which is only seen in trisomy 21 patients. Cytogenetic studies were positive for mosaic trisomy 21.

Transient Myeloproliferative Disorder in a Neonate without Down Syndrome—A Rare Case Report and Review of the Literature

“…5 Trisomy-21, either constitutional or mosaic, or even limited to the hematopoietic compartment, as in our patient, has been reported universally in TMD. 2 Trisomy-21 mosaicism has been described in 7 to 16% of cases of TMD. The risk of developing TMD or subsequent leukemia and the prognosis was not different in those with overt DS and mosaic DS.…”

“…Constitutional mosaicism can be difficult to prove, especially in the setting of hematopoietic abnormalities; therefore, further testing is warranted in this patient population. 2,6 Pathogenesis of TMD is linked to the mutations in GATA-1 in X-chromosomes, most common being the exon-2 mutations. GATA-1 is vital in the normal erythropoiesis and megakaryopoiesis.…”

“…1 DS with somatic mosaicism has been brought to light with a diagnosis of TMD at birth. 2 TMD with the absence of features of DS and constitutional karyotypic abnormalities is meagerly reported in the literature.…”