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What is congenital amegakaryocytic thrombocytopenia?

Congenital amegakaryocytic thrombocytopenia (CAMT) is a rare, inherited disorder characterized by a severely low number of megakaryocytes, a type of bone marrow cell that makes platelets that are important for clotting and preventing bleeding. Initially, the bone marrow no longer makes platelets; over time, the bone marrow may stop making red and white blood cells, as well.

CAMT is usually diagnosed anywhere from birth to nine months but often in a child’s first month of life. There are two forms of the disease:

  • Group I CAMT — severe, persistent thrombocytopenia (low platelet count) and early onset of pancytopenia (low red and white blood cell count)
  • Group II CAMT — temporary increase in platelets early in life, with possible later development of pancytopenia

Symptoms & Causes

What are the symptoms of CAMT?

The most common symptoms of CAMT are:

  • Bruising
  • Bleeding, which can be life-threatening
  • Petechiae — tiny red dots under the skin that are a result of very small bleeds into the skin

Children with CAMT can also have central nervous system abnormalities, retardation of psychomotor development, cardiac defects, and other rare malformations.

Diagnosis & Treatments

How is congenital amegakaryocytic thrombocytopenia diagnosed?

Initially, CAMT can be misdiagnosed as immune thrombocytopenia (ITP), an autoimmune disorder that occurs when the body destroys platelets too quickly. CAMT is diagnosed with:

  • Blood tests to determine low platelet count
  • Bone marrow evaluation to examine megakaryocytes and other blood-forming cells
  • Genetic testing to confirm the diagnosis

After all tests are completed, doctors will be able to outline the best treatment options.

How is congenital amegakaryocytic thrombocytopenia treated?

Treatments for congenital amegakaryocytic thrombocytopenia (CAMT) include:

What is the long term outlook for children with CAMT?

With supportive therapy alone, the progression to bone marrow failure usually occurs in a child’s first decade of life. A stem cell transplant is the only curative therapy and is successful for over 50 percent of patients. Patients with CAMT may be at increased risk of developing acute myelogenous leukemia or myelodysplastic syndrome.

How we care for CAMT

Children with CAMT receive treatment at Dana-Farber/Boston Children’s Cancer and Blood Disorders Center through our Bone Marrow Failure Program. Continue reading to learn more about congenital amegakaryocytic thrombocytopenia or visit the Bone Marrow Failure and Myelodysplastic Syndrome Program page to learn about our expertise and treatment options.

Cancer and Blood Disorders Center

The Dana-Farber/Boston Children's Cancer and Blood Disorders Center is an integrated pediatric hematology and oncology program through Dana-Farber Cancer Institute and Boston Children’s Hospital.

Call 617-355-8246