Transient abnormal myelopoiesis in a cytogenetically normal neonate

Abstract

We present a cytogenetically normal neonate who developed transient abnormal myelopoiesis. The blasts showed trisomy 21. In contrast, fibroblasts, and PHA-stimulated peripheral blood demonstrated normal diploid line on extensive karyotyping. Direct sequencing of the DNA derived from the peripheral blood at overt disease revealed splice site mutation in the boundary of GATA1 exon 2. The patient received three courses of chemotherapy leading to complete remission. During the complete remission, there was neither mutation of GATA1 exon 2 nor trisomy 21, confirming somatic nature of both abnormalities. The patient is now free from the disease 12 months after remission. This case emphasizes the significance of trisomy 21 as the cause of transient abnormal myelopoiesis in Down syndrome.

Transient abnormal myelopoiesis in non‐Down syndrome neonate

“…4 TAM and subsequent AMKL in phenotypically normal infants is less common. [5][6][7][8] Here we report a non-DS case in which AMKL with the trisomy 21 and GATA1 mutations pathologically mimicked TAM.…”

“…Thus, it is speculated that the combination of the growth advantage by trisomy 21 and the differentiation blockage by GATA1 mutation contributes to AMKL development. TAM in non‐DS patients has only occasionally been reported …”

“…TAM in non-DS patients has only occasionally been reported. [5][6][7][8] Two hypotheses are proposed for the development of TAM in non-DS patients. The first hypothesis is that bone marrow of phenotypically normal non-DS patients consists of trisomy 21 mosaicism at a low frequency, and acquires de novo mutation of GATA1, which leads to TAM.…”

“…Further mutation in cohesin or CTCF , EZH2 or other epigenetic regulators, and RAS or signal‐transducing molecules, leads to development of AMKL . TAM and subsequent AMKL in phenotypically normal infants is less common . Here we report a non‐DS case in which AMKL with the trisomy 21 and GATA1 mutations pathologically mimicked TAM.…”