Radial aplasia is a birth defect that affects the radius bone, one of two long bones in the forearm. It includes defects where the bone is not present or shorter than usual and results in an abnormal appearance of the arm. In most cases both forearms are affected. Sometimes the bones of the wrist and fingers can also be affected.
Developing very early in the pregnancy, this is a rare defect that affects 1 in 30,000 babies.
There are a number of causes of radial aplasia, including poorly controlled diabetes in the mother, medications taken early pregnancy or by a yet to be diagnosised genetic condition. When radial aplasia is identified, a thorough ultrasound of the fetal body is performed to look for other defects. Amniocentesis is also recommended to test for genetic abnormalities. There is no available treatment while the fetus is in utero.
Depending on the severity of the arm defects, some infants will need to be delivered by C-section. After birth, pediatricians will examine the infant and perform an X-RAY. Blood tests are also performed. Radial aplasia is initially corrected by placing casts or splints along the abnormal arm. If surgery is needed, it usually occurs within the first year of life. The prognosis depends on whether there are other associated birth defects or genetic problems. If there are no other abnormalities present, many children lead independent lives with physical therapy and treatments to improve function of the arm(s).