Question:

What causes webbed toes? My son was born with this on both feet. One is a lot wrose than the other foot. He also has a tiny big of webbing on his bottocks crease.

Answer:

Webbed toes or syndactyly is the term used for when the skin between the toes or fingers does not disappear as it is supposed to during fetal development.  This usually happens very early in pregnancy – about 6 weeks.  The fingers and toes are normally webbed until 6 weeks of fetal development when the skin between the fingers and toes starts to disappear. 

Syndactyly can run in families.  It can be inherited as an autosomal dominant problem – that means that there is a single gene that codes for this abnormality in the family.  Anyone with the gene has a 50-50 chance of passing on the gene that causes syndactyly – thus any child born to a person with the gene that causes syndactyly – or webbing – has a 50-50 chance of inheriting the gene and having syndactyly.

This is a very common birth defect.  However, it can be associated with other problems.  You should look to see if you or your spouse have webbing or webbing in your families – since this birth defect runs in families and is inherited in an autosomal dominant fashion – that is, anyone with the gene has a 50-50 chance of passing it on.

Also, some people have the gene for this birth defect and do not know it.  Other family members may have a very mild form of the birth defect  – just a little bit of webbing, so it may be helpful to ask your family about webbing between their toes or fingers.

Finally, if the baby has any other problems, you might want to consult with a geneticist or genetic counselor to discuss this problem in more detail. You can locate a geneticist or genetic counselor near you by going to the NSGC website (www.nsgc.org), click on your city, and genetics professionals will come up as those being the closest to you.  You can also ask your pediatrician for some assistance in finding the most appropriate and knowledgeable person in the field. 

For more information:

Go to the Inherited Disorders and Birth Defects health topic.