The eosinophil is a white blood cell reddish granules. It is usually associated with allergies and asthma. Many individuals with TAR seem to have an allergy to cow's milk and they will usually be found to have an increase in the eosinophils. Individuals with TAR often have anaemia or low red cells. This can be because of bleeding but it is thought that during the first year of life, fewer red cells are made than in the average individual.
Affected individuals tend to outgrow anaemia.
The consistent feature of TAR is absence of the radius but presence of the thumb. The legs may be affected as well. There can be dislocation of the hips so that the head of the femur doesn't sit properly into the hip socket. There can be abnormalities of the knees leading to bending abnormally one way or the other, loose kneecaps, or the bones of the knee slipping on each other. Occasionally the bones of the knee are even fused.