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Polydactyly

Definition:

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

Alternative Names:

Extra digits; Supernumerary digits

Considerations:

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.

Common Causes:

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

Polydactyly - an infant's hand

Review Date: 3/13/2006
Reviewed By: Lamya Alarif, Ph.D., H.C.L.D., Immunology and Genetics Associates, McLean, VA. Review provided by VeriMed Healthcare Network.

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