Definition

Thrombocytopenia-absent radius (TAR) syndrome is a rare condition that is apparent at birth. Affected infants are born with incomplete or missing forearms. Typically, the bone on the thumb side of the forearm (radius) is absent, but other bones may be missing or abnormally formed. TAR syndrome also causes life-threatening bleeding episodes due to low levels of platelets in the blood (thrombocytopenia). It is inherited in an autosomal recessive manner.

Affected infants are born with incomplete or missing forearms. Usually, it's the radius that is missing, but other bones may be missing or abnormally formed. It also causes fatal bleeding episodes due to low levels of platelets in the blood (thrombocytopenia).