Background Transient abnormal myelopoiesis (TAM) is a unique myeloproliferative disorder that occurs in neonates with constitutional trisomy 21/Down syndrome (DS). Although TAM also develops in neonates without constitutional trisomy 21, the clinical, cytogenetic, and molecular characteristics of those patients are not fully understood. Procedure We retrospectively evaluated the clinical and cytogenetic findings and GATA1 mutation status of 17 neonates with TAM and nonconstitutional trisomy 21 tested for GATA1 mutations at our institute, and compared the findings with those of 64 neonates with TAM and constitutional trisomy 21/DS. Results DS clinical features were observed in five of the 17 (29%) patients. In all patients, both trisomy 21 and GATA1 mutations were detected in diagnostic samples. Over a median follow‐up of 33 (range, 0‐139) months, early death (< 6 months of age) occurred in four patients (24%). Overall and event‐free survivals were not significantly different between the patients with TAM and nonconstitutional trisomy 21 and those with TAM and constitutional trisomy 21/DS (five‐year overall survival: 76% ± 10% vs 53% ± 13%, P = 0.40; five‐year event‐free survival: 55% ± 13% vs 48% ± 12%, P = 0.90). The five‐year cumulative incidence of progression to myeloid leukemia of DS was also similar between the groups (21% vs 24%, P = 0.80). Conclusions Patients with TAM and nonconstitutional trisomy 21 exhibited similar biology and outcomes to those with TAM and constitutional trisomy 21/DS. The possibility of TAM should be considered even in phenotypically normal neonates with TAM symptoms, for appropriate management.

Although thiopurine is a crucial drug for treating acute lymphoblastic leukemia, individual variations in intolerance are observed due to gene polymorphisms. A 3-year-old boy with B-cell precursor acute lymphoblastic leukemia who was administered thiopurine developed mucositis, sepsis, and hemophagocytic lymphohistiocytosis due to prolonged hematologic toxicity, chronic disseminated candidiasis, and infective endocarditis that triggered multiple brain infarctions. The patient was found to harbor 3 gene polymorphisms associated with thiopurine intolerance including homozygous NUDT15 R139C, heterozygous ITPA C94A, and homozygous MTHFR C677T and heterozygous RFC1 G80A. Thus, the combined effect of intolerance via multiple gene polymorphisms should be considered in case of unexpected adverse reactions.

Infantile umbilical hernia is a common condition that occurs in 10%-20% of all infants, 1 and previous studies reported that spontaneous observation shows a cure rate of 80% by 2 years of age 2 and 85% by 6 years of age. 3 Spontaneous observation has the advantage of not requiring any treatment; however, it also has a disadvantage, such as in cases when the hernia orifice does not close or the umbilical protrusion remains after closure. Therefore, compression therapy has been proposed as a conservative treatment and is reported in several studies. 2,[4][5][6][7][8] Compression therapy has the advantages of early closure compared with spontaneous observation 4,7,9,10 and a high rate of hernia