Early indicators of neonatal-onset hereditary thrombotic thrombocytopenia purpura.

ABSTRACT

Background: Neonatal-onset hereditary thrombotic thrombocytopenia purpura (hTTP) is often misdiagnosed due to its rarity. It begins with jaundice, similar to infants with ABO incompatibility. Objective: To explore early indicators of neonatal-onset hTTP. Methods: This study was a retrospective case series of newborns with hTTP and ABO incompatibility. We compared the clinical characteristics and laboratory test results in these two groups. Results: This study included four hTTP patients and 20 ABO-incompatible newborns. All patients manifested disease during the neonatal period. There were equal numbers of males and females in each group. hTTP newborns showed earlier (median difference, 57.0 h; 95% confidence interval [CI], 24.0-65.0) and more severe hyperbilirubinemia (mean difference, 8.0 mg/dl; 95% CI, 3.8-12.1) than ABO-incompatible newborns. In hTTP newborns, anemia was more common within 7 days after birth than in ABO-incompatible newborns (odds ratio, 25.4; 95% CI, 1.2-551.6), and platelet counts were lower than in ABO-incompatible newborns (17 ± 12 × 109/L vs. 291 ± 76 × 109/L). The levels of serum creatinine (median difference, 51.8 µmol/L; 95% CI, 16.0-109.4) and blood urea nitrogen (median difference, 5.7 mmol/L; 95% CI, 2.8-38.7) were higher in hTTP newborns than in ABO-incompatible newborns. There were no significant differences in white blood cell counts, C-reactive protein, alanine aminotransferase, or albumin levels. Conclusions: Severe jaundice soon after birth, early anemia, and severe thrombocytopenia were more common in newborns with hTTP than ABO incompatibility. These are distinguishing early features of hTTP.