Thumb Aplasia

What Is Thumb Aplasia?

Thumb aplasia is a congenital defect in which a baby is born without a thumb.

At the Yale Hand and Microsurgery Program, we know that it can be alarming to see that one of your child’s digits is missing. We also know that you may have many questions regarding your child’s condition and treatment options. Our surgeons and clinical specialists will answer all your questions in detail. It is important to us that you feel comfortable with every part of your child’s treatment.

Causes of Thumb Aplasia

The exact cause of thumb aplasia is not yet known. It is very rare, occurring in about 1 out of 100,000 live births. Often, parents have feelings of guilt when there is no genetic predisposition to their child’s birth defect. In the case of thumb aplasia, there has been no connection to anything that might have happened during pregnancy and the malformation or absence of a child’s digit. 

Sometimes thumb aplasia is associated with a syndrome, such as Holt-Oram and Fanconi. It also commonly occurs with radial club hand.  If your baby was born without a thumb, our doctors will perform further tests to see if the deformity occurs alone or if it is a part of syndrome.

Treatments for Thumb Aplasia

Even without a thumb, children adapt very well, learning how to use other fingers to function as the thumb normally would. If your child has a problem with developing fine motor skills, such as pinching and grasping, he or she may require surgery for correction. 

Treatment for thumb aplasia can be very complex and varies from child to child. At the Yale Hand and Microsurgery Program, we create a treatment plan for your child based on the severity of the condition, whether it occurs alone or as part of a syndrome, the overall health of your child, as well as your thoughts and feelings about your child and his or her overall well-being. 

Generally, surgery to correct thumb aplasia is done between 6 and 18 months old. When the thumb is absent, a technique called pollicization is performed, in which the index finger is transferred to the area of the thumb.