Thumb Hypoplasia/Aplasia Symptoms & Causes

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What causes an underdeveloped or absent thumb?

Researchers still haven’t discovered the exact cause of this condition.

How common is an underdeveloped or absent thumb?

It’s rare, occurring in about 1 out of every 100,000 babies.

   •   It can occur by itself or may be associated with other conditions where the
       radial side (thumb side) of the forearm does not develop properly.
   •   These include Holt-Oram and Fanconi Syndromes.
   •   It’s also routinely seen with radial club hand.

In some cases, both the right and left hands may be affected.

What symptoms might my child have?

Because of the reduced functionality of your child’s thumb, he may have some problems with using his hand.

What’s going to happen to my child?

Children will adapt and can function without a missing finger. Children who have no use of a thumb will learn to rely on a lateral pinch between the long and index fingers.

However, they may have problems with fine motor activities such as pinching and grasping. It is these children who may require surgery to correct the problem.

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