Polydactyly is having more than five fingers per hand or toes per foot.

Having an abnormal numbers of digits (6 or more) can occur on its own, that is, not linked to any other symptoms or disease. Polydactyly may occur in families as a dominantly inherited trait that involves only one gene that can cause several variations.

African Americans, more than other ethnic groups, commonly inherit a 6th finger as a dominant trait. In the majority of cases, this does not indicate any genetic disease.

Polydactyly can also occur in conjunction with some genetic diseases.

Extra digits may be extremely rudimentary and attached by a small stalk (generally on the little finger side of the hand) or fairly well-formed and even functional. Rudimentary digits are generally removed. Simply tying a tight string around the stalk can cause it to fall off in time.

Larger digits may require surgery to be removed. Removal of these rudimentary digits means that careful questioning of parents must be done regarding whether there was polydactyly at birth because a person may not ever know they had it.

• Familial polydactyly (inherited trait)
• Ellis-van Creveld syndrome (chondroectodermal dysplasia)
• Carpenter syndrome
• Trisomy 13
• Rubinstein-Taybi syndrome
• Smith-Lemli-Opitz
• Laurence-Moon-Biedl syndrome
• Asphyxiating thoracic dystrophy

Home care may be required if surgery is used to remove an extra digit. For example, inspection of the incision to make sure that appropriate healing is taking place and to change the dressing.

This condition is normally discovered at birth and evaluated during the newborn hospital stay.

The doctor will take a medical history and perform a  physical examination.

Medical history questions may include:

• Have any other family members been born with extra fingers or toes?
• Is there a known family history of any of the disorders that can be associated with polydactyly?
• What other symptoms or abnormalities are also present?

Physical examination:

An infant with polydactyly may have other symptoms and signs that, when taken together, define a specific syndrome or condition. Diagnosis of that condition will be based on a family history, medical history, and thorough physical evaluation.

Diagnostic tests:

Laboratory studies such as chromosome studies, enzyme assays, x-rays, and metabolic studies may be done to confirm a suspected disorder.

After seeing your health care provider:

You may want to add a note to your personal medical record indicating that polydactyly was present, any diagnosis related to it, and any treatment done.

Prenatal diagnosis may involve ultrasound or more-advanced embryofetoscopy during the first trimester.