Thursday, June 30, 2016
Inherited Disorders and Birth Defects
My father, myself and my son all have webbed toes. My son had a baby last year who did not have webbed toes. Someone has told me that the baby should have webbed toes because it is genetic. Can you confirm?
Syndactyly or webbing of the fingers and toes is a very common finding which can be a normal variation or minor anomaly. If the webbing only goes about a third of the way up between the toes, it is said be a variation of normal. If the webbing goes further than this – it is said to be a minor abnormality.
Syndactyly can be sporadic - that is, it can happen in just one child in a family, is not inherited from either parent and geneticists do not know why it happened. It can also run in families – where a parent has syndactyly and can pass it on to any of his or her children.
In your case, it sounds like your family has a gene that codes for syndactyly and is probably inherited in what is called autosomal dominant inheritance. For all of our genes – there are 2 copies of each. Autosomal dominant inheritance describes a trait or disorder in someone who has a gene mutation (or change) in one of the two copies for that specific gene. That gene mutation specifically refers to a gene on one of the 22 pairs of autosomes (non-sex chromosomes).
Anyone with an autosomal dominant inherited trait or disorder has a 50-50 or 1 out of 2 chance of passing that gene on to any child that person has. If someone had 100 children, you would expect that half would have webbed fingers or toes and half would not. Autosomal dominant traits can be seen in both males and females equally. In your family, it appears that your son did not pass on the gene for syndactyly to his baby.
Anne Matthews, RN, PhD
Associate Professor of Genetics
School of Medicine
Case Western Reserve University