Changes in Blood Test Indices of Infants With Down Syndrome-Associated Transient Abnormal Myelopoiesis.

Background: Approximately 20% of infants with Down syndrome-associated transient abnormal myelopoiesis (TAM) die at an early age, mainly because of liver failure.

Objective: To identify post-diagnosis changes in blood test indices that could predict TAM-related deaths as early as the postnatal period.

Methods/results: This was a single-center retrospective study. Of the 505 children with Down syndrome admitted to our hospital from 1992 to 2024, we studied 12 infants with TAM-related death and 39 survivors. In the death and survival groups, the median gestational ages were 34.9 and 37.1 weeks, respectively (p = 0.146). At birth, the white blood cell (WBC) counts were 99.2 and 41.7 × 10⁹/L (p = 0.027), and the serum direct bilirubin (D-Bil) concentrations were 20 and 17 µmol/L (p = 0.45), respectively. After the first week of age, the WBC counts, blast percentages, platelet counts, and serum alanine aminotransferase and aspartate aminotransferase concentrations were similar between the groups. At 1 week of age, the serum D-Bil concentrations were 32 and 21 µmol/L (p = 0.007), respectively. At 2 weeks, they were 94 and 27 µmol/L (p < 0.001), respectively. The area under the receiver operating characteristic curve for the ability of serum D-Bil at 2 weeks to predict death was 0.94, with a threshold of ≥51 µmol/L (approximately 3.0 mg/dL) yielding a sensitivity of 1.00 and a specificity of 0.78.

Conclusion: A serum D-Bil concentration of ≥51 µmol/L at 2 weeks of age may serve as a useful predictor of TAM-related death.