Polydactyly (from Ancient Greek (polus) “many” and (daktulos) “finger”) is a condition in which a person (or animal) has more than five fingers per hand or five toes per foot. The condition has an incidence of 1 in every 500 live births.
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, though it 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.