Skip to main content

Thrombocytopenia Absent Radius Syndrome

Thrombocytopenia Absent Radius Syndrome

OMIM number: 274000

Comments closing date: 27/03/2020

Share information with the HFEA

Thrombocytopenia-Absent-Radius Syndrome (also known as TAR Syndrome) is a rare hereditary condition which mostly affects the bones, but also can affect the heart or kidneys. People with TAR syndrome inherit mutations in both copies of their RBM8A genes. They are almost always born without a specific bone in their arms called the radius. Another arm bone (the ulna) is often missing or smaller than average. They can have other changes to their bones, such as webbed hands, curved fingers, or problems with their upper arms, legs, or hips. They also have a low amount of platelets in their blood, which is called Thrombocytopenia. This means that the blood is not able to clot in response to injury, which can lead to excessive and potentially life-threatening bleeding episodes. Major bleeding events are particularly common in the first year of life, which can lead to permanent organ damage. These episodes are less common as people get older. Other organs can be affected, and include abnormalities of the structure of the heart, kidneys, and female reproductive system.

Review date: 26 February 2022