Medical Q&As

Polydactyly - could my baby inherit this?

I had a condition when I was born called polydactyly, which means that I was born with extra digits. My son was also born with this condition. I am expecting another baby in a few months. What are the chances of this baby having the same condition?

Polydactyly is probably the most common abnormality of development found at birth. I suspect that both you and your son have the common form of polydactyly, which is due to an autosomal dominant form of inheritance. This form of polydactyly is not associated with additional congenital abnormalities and has no health implications for you or your children. An autosomal dominant form of inheritance means that there is a one in two chance at each pregnancy that the child will have polydactyly. Equally there is a 50% chance that the child wont have it. Boys and girls are equally likely to be affected. Sometimes the digit can be so rudimentary that it is not much bigger than a skin tag. In the past it was quite common for the doctor attending at the birth to tie a ligature around the boneless skin tag, which lead to the tiny digit falling off in the following days. It is quite possible that one of your parents had such a digit but it was removed in the manner I have described at birth. Such matters were regarded as being so minor a curiosity that they were not recorded.