Polydactyly is a condition in which a person has more than five fingers per hand or five toes per foot.
Extra digits; Supernumerary digits
Having an abnormal number of digits (6 or more) can occur on its own, without any other symptoms or disease. Polydactyly may be passed down (inherited) in families. This trait involves only one gene that can cause several variations.
African Americans, more than other ethnic groups, can inherit a 6th finger. In most cases, this is not caused by a genetic disease.
Polydactyly can also occur with some genetic diseases.
Extra digits may be poorly developed and attached by a small stalk (generally on the little finger side of the hand). Or, they may be well-formed and may even function. Poorly formed digits are usually removed. Simply tying a tight string around the stalk can cause it to fall off in time if there are no bones in the digit.
Larger digits may need surgery to be removed. The doctor should ask the parents whether there was polydactyly at birth, because a person may not know they have it.
After seeing your health care provider, you may want to add a note to your personal medical record about polydactyly, its diagnosis, and treatment.
During pregnancy, this condition may be diagnosed with ultrasound or a more advanced test called embryofetoscopy during the first three months (trimester).
Hosalkar HS, Spiegel DA, Davidson RS. Toe deformities. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 666.10.
Neil K. Kaneshiro, MD, MHA, Clinical Assistant Professor of Pediatrics, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.