Upshaw–Schulman syndrome

Blood smear with typical schistocytes in TTP marked in blue 1

Upshaw–Schulman syndrome

Upshaw–Schulman syndrome (USS) is a rare, inherited blood disorder characterized by a deficiency in the ADAMTS13 enzyme. This enzyme is crucial for cleaving von Willebrand factor (vWF), a protein involved in blood clotting. The deficiency leads to the accumulation of unusually large vWF multimers, which can cause spontaneous formation of blood clots in small blood vessels throughout the body, a condition known as thrombotic thrombocytopenic purpura (TTP).

Signs and Symptoms

Individuals with Upshaw–Schulman syndrome may experience a variety of symptoms, including:

• Thrombocytopenia (low platelet count)
• Hemolytic anemia (destruction of red blood cells)
• Neurological symptoms such as headaches, confusion, and seizures
• Renal dysfunction (kidney problems)
• Fever

Pathophysiology

The primary cause of Upshaw–Schulman syndrome is mutations in the ADAMTS13 gene, which result in reduced or absent activity of the ADAMTS13 enzyme. This enzyme normally cleaves large multimers of von Willebrand factor into smaller units, preventing excessive clot formation. In the absence of functional ADAMTS13, these large multimers persist and promote platelet aggregation and clot formation in small blood vessels.

Diagnosis

Diagnosis of Upshaw–Schulman syndrome typically involves:

• Measurement of ADAMTS13 activity levels
• Genetic testing to identify mutations in the ADAMTS13 gene
• Blood tests to assess platelet count, hemoglobin levels, and the presence of schistocytes (fragmented red blood cells)

Treatment

Treatment for Upshaw–Schulman syndrome often includes:

• Plasma exchange to remove large vWF multimers and replenish ADAMTS13
• Fresh frozen plasma infusions to provide functional ADAMTS13
• Immunosuppressive therapy in cases where an autoimmune component is suspected

Prognosis

With appropriate treatment, individuals with Upshaw–Schulman syndrome can manage their symptoms and prevent severe complications. However, the condition requires lifelong monitoring and treatment to prevent relapses.

Related Pages

• Thrombotic thrombocytopenic purpura
• ADAMTS13
• Von Willebrand factor
• Blood clotting
• Hemolytic anemia
• Thrombocytopenia