Progressive Thrombosis in a 13-Year-Old Girl with Trisomy 21 Under Therapy with Low Molecular Weight Heparin

Introduction ▼ Antiphospholipid syndrome (APS) is a rare and serious autoimmune condition in childhood [2] . APS is defi ned by arterial and / or venous thromboses in the presence of antiphospholipid antibodies (APAs) detected on 2 or more conditions at least 12 weeks apart [5] . Recognition of APS remains challenging, especially because the clinical features are often discrete [10] and the laboratory tests applied are heterogenous [3] . In contrast to adulthood, increased APA titers may occur in a variety of diseases in children and adolescents [1] . However, the frequency of APA-related symptoms is low [4] and children with APAs generally do not experience a high rate of thrombotic events [6] except in cases with predisposing anatomic anomalies [8] . The syndrome is underrecognised and underdiagnosed and can have severe consequences if untreated, mainly because of progressive thrombosis and embolism [2] .