A person with polydactyly is one who is born with additional fingers or toes. The words “many” (“poly”) and “digits (“dactylos”) are both Greek.

Different kinds of polydactyly exist. The additional digit typically develops near the fifth finger or toe.

Polydactyly tends to run in families. It may also result from genetic mutations or environmental causes.

The usual treatment is surgery to remove the extra digit.

Polydactyly signs and symptoms

A person with polydactyly has additional fingers or toes on either one or both of their hands or feet.

The additional digit or digits could be

  • complete and working in its entirety
  • a tiny mass of soft tissue (called a nubbin)
  • some partially formed bone

Polydactyly types

Most frequently, polydactyly occurs by itself. This is called Isolated or nonsyndromic polydactyly.

It sometimes has a connection to another hereditary condition. This is called syndromic polydactyly.

Isolated polydactyly

According to where the additional digit is located, there are three different types of isolated polydactyly:

  • Postaxial polydactyly: It develops on the outside of the hand or foot, where the fifth digit is located. This is known as the ulnar side of the hand. This kind of polydactyly is the most common.
  • Preaxial polydactyly: It affects the thumb or big toe inside of the hand or foot. This is referred to as the radial side of the hand.
  • Central polydactyly: It develops in the middle digits of the hand or foot. It is the least common kind.

Syndromic polydactyly

Compared to isolated polydactyly, syndromic polydactyly is substantially less common. Only 14.6% of the 5,927 individuals with polydactyly examined in a 1998 study by a reliable source had a genetic abnormality at birth.

Polydactyly is linked to a wide variety of unusual diseases, such as developmental and cognitive abnormalities as well as head and facial malformations. In 2010, researchers classified 290 diseases that were associated with polydactyly.

Specific genes and mutations that cause many of these disorders can now be found because of improvements in genetic methods. The 2010 study discovered 99 gene mutations linked to some of these conditions.

Doctors are better able to identify and treat various disorders in infants born with polydactyly, with this detailed understanding of genetics.

Syndromes associated with polydactyly

Here are a few of the genetic syndromes associated with polydactyly:

  • Down syndrome is strongly associated with double thumbs.
  • Syndactyly involves digits that are fused or weblike. A 2017 study estimated that this occurs in 1 in 2,000 to 3,000 births.

Symptoms related to polydactyly

Several hereditary syndromes linked to polydactyly are listed below:

  • Double thumbs are closely related to down syndrome.
  • The digits of syndactyly are fused or weblike. According to a 2017 study, this happens in 1 in every 2,000 to 3,000 births.
  • Early skull bone fusion and syndactyly are both involves in acrocephalosyndactyly.
  • Greig syndrome is characterised by defective limb, head, and facial development. It also occurs to have fused or additional digits, a broad thumb or big toe, or extra digits.
  • Carpenter syndrome is characterised by a pointed head with polydactyly in the first or second toe or fifth finger.
  • A double first toe and syndactyly between the second and third digits are two characteristics of Saethre-Chotzen syndrome.
  • Polydactyly – and syndactyly in the fingers and toes are symptoms of Bardet-Beidl syndrome.


  • McKusick-Kaufman syndrome involves heart defects, genital abnormalities, and polydactyly.
  • Polydactyly, genital abnormalities, and cardiac problems are all a part of McKusick-Kaufman syndrome.
  • Developmental disorders are a part of the Cornelia de Lange syndrome.
  • Syndactyly and developmental flaws are linked to Pallister-Hall syndrome.