A case of inherited thrombocytopenia required a differential diagnosis of immune thrombocytopenia

Abstract

Inherited thrombocytopenia is a heterogeneous disorder characterized by mutations in various genes. It is often misdiagnosed as chronic immune thrombocytopenia (cITP). A two-year-old boy was admitted to our hospital because of a fever and petechiae. His family had four individuals with thrombocytopenia, and a genetic analysis of his father conducted 20 years ago showed no abnormalities. A blood examination of the patient showed a platelet count of 16×10⁹/L and anti-cardiolipin antibodies of 12 U/mL. His follow-up platelet counts transiently increased to 396×10⁹/L on the 6th day, even without specific treatment. However, subsequent platelet counts ranged between 50×10⁹ and 60×10⁹/L. Genetic analyses of the patient and his parents performed at 3y11m after approval of the ethics committee showed ANKRD26 c.-134 G>A variant in both the patient and his father. Finally, we diagnosed the boy with Thrombocytopenia 2 (THC2). Diagnosing Inherited thrombocytopenia can be challenging, particularly as it is often mistaken for ITP. Therefore, precise identification requires a thorough evaluation, including genetic analysis.