Congenital Amegakaryocytic Thrombocytopenia

Also known as: CAT, CAMT.

What is congenital amegakaryocytic thrombocytopenia?

Megakaryocytes are formed in the bone marrow from an early stem cell, and they, through a complex process produce platelets which play a very important role in blood clotting and the prevention of bleeding.

CAT is a rare disorder (there are two types) found in infants where there are very few megakaryocytes and platelets in bone marrow, and while initially the bone marrow produces red and white cells this eventually decreases /stops so the baby/child has a lack of platelets, red cells and white cells.

Children with CAT may be at risk for other bone marrow diseases.

What causes CAT?

CAT is an inherited congenital disorder (babies are born with it) caused by mutations (changes) in a specific gene.

What are the signs or symptoms of congenital amegakaryocytic thrombocytopenia?

Children with CAT tend to bruise easily, can experience life-threatening bleeding or have tiny red dots under the skin from bleeding (called petechiae). They may also have abnormalities of brain function, heart problems and other malformations.

What are CAMT?

Children with CAT frequently need blood transfusions. A stem cell transplant can cure the disease in some patients..

Reviewed by: Jack Wolfsdorf, MD, FAAP

This page was last updated on: September 09, 2025 10:21 AM