[A child with relapsing haemolytic anemia and thrombocytopenia]

A newborn Norwegian girl of non-consanguineous parents developed petechial bleeding, severe thrombocytopenia, and hyperbilirubinemia within 24 hours of birth. Severe anemia, macroscopic hematuria, and elevated creatinine developed during the first week of life. She was treated with blood transfusions and intravenous immunoglobulins. At the age of 9 months, she developed petechiae and jaundice during the course of an upper respiratory tract infection, and was readmitted to hospital. Thrombocytopenia was discovered and she received intravenous immunoglobulins. During the following months the girl was repeatedly seen at the paediatric outpatient clinic for petechial bleeding and moderate thrombocytopenia. At the age of 20 months, ADAMTS (a metalloprotease-disintegrin with thrombospondin type 1 domains)-13 activity was found to be absent. No inhibitor was detected in her plasma. Both parents and her younger sister had ADAMTS-13 activity of 50 %, establishing the diagnosis of severe congenital ADAMTS-13 deficiency. She is now treated with fresh frozen plasma infusions every 14 days.

Assay of ADAMTS-13 helps to diagnose a form of thrombotic thrombocytopenic purpura which may be managed by prophylactic treatment with fresh frozen plasma.