Radio-ulnar synostosis-amegakaryocytic thrombocytopenia syndrome

Radio-ulnar synostosis with amegakaryocytic thrombocytopenia (RUSAT) is a rare inherited condition that affects both the bones of the forearm and the blood. The name describes the two main problems: 'radio-ulnar synostosis' means the two bones in the forearm (the radius and ulna) are fused together, and 'amegakaryocytic thrombocytopenia' means the bone marrow does not make enough of the cells (called megakaryocytes) that produce platelets — the tiny blood cells that help stop bleeding. Because of the fused forearm bones, people with RUSAT have limited ability to rotate their forearms — for example, turning the palm up or down is difficult or impossible. This can affect everyday tasks like typing, eating, or carrying objects. The low platelet count (thrombocytopenia) means the blood does not clot well, leading to easy bruising, frequent nosebleeds, and a risk of serious bleeding. Over time, some people develop bone marrow failure, where the marrow stops making enough of all blood cell types, which is a life-threatening complication. RUSAT is caused by changes (mutations) in specific genes, most commonly HOXA11 or MECOM. Treatment focuses on managing the low platelet count and monitoring for bone marrow failure. In severe cases, a bone marrow transplant (stem cell transplant) may be needed. The arm fusion itself is usually managed with physical or occupational therapy, and sometimes surgery. This condition is also sometimes called Radioulnar Synostosis with Amegakaryocytic Thrombocytopenia syndrome.

Bring these to your next appointment

• Q1.How severe is my child's platelet count problem, and what level would trigger a need for transfusion or transplant?,Should we do genetic testing on other family members to see if they are affected or are carriers?,When should we start looking for a bone marrow transplant donor, and what are the risks and benefits of transplant for my child?,What activities or sports should my child avoid because of the bleeding risk?,How often should we have blood counts checked, and what warning signs should make us go to the emergency room?,Are there any clinical trials or research studies we could join?,What support services — such as occupational therapy or social work — are available to help our family?

Common questions about Radio-ulnar synostosis-amegakaryocytic thrombocytopenia syndrome

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