Polydactyly

This article is about the human congenital disorder (disease). For the paleontological application, see Dactyly.

Polydactyly
Specialty	Medical genetics

Polydactyly or polydactylism (from Ancient Greek πολύς (polus) "many" + δάκτυλος (daktulos) "finger"), also known as hyperdactyly, is a congenital physical anomaly consisting of supernumerary fingers or toes. When each hand or foot has six digits, it is sometimes called "sexdactyly", "hexadactyly", or "hexadactylism". Although the condition is usually not life-threatening or even particularly debilitating, most people in Western societies have the extra digits removed surgically.

The extra digit is usually a small piece of soft tissue; occasionally it may contain bone without joints; rarely it may be a complete, functioning digit. The extra digit is most common on the ulnar (little finger) side of the hand, less common on the radial (thumb) side, and very rarely within the middle three digits. Hrithik Roshan, a Bollywood film star, is an example of this. He has an extra thumb on his right hand. The extra digit is most commonly an abnormal fork in an existing digit, or it may rarely originate at the wrist like a normal digit does.

Polydactyly can occur by itself, or more commonly, as one feature of a syndrome of congenital anomalies. When it occurs by itself, it is associated with autosomal dominant mutations in single genes, i.e. it is not a multifactorial trait.[1] But mutation in a variety of genes can give rise to polydactyly. Typically the mutated gene is involved in developmental patterning, and a syndrome of congenital anomalies results, of which polydactyly is one feature.

The condition has an incidence of 1 in every 500 live births although the frequency is higher in some groups (an example is the Amish in the United States, due to the founder effect).

Left foot with postaxial polydactyly of 5th ray

Right hand with mid-ray duplication

Types of polydactyly

• Polydactyly with cleft lip/palate and psycho motor retardation (Varadi-Papp Syndrome)
• Polydactyly tiopia syndrome
• Polydactyly post axial dental and vertebral
• Polydactyly post axial with median cleft of upper lip
• Polydactyly post axial
• Polydactyly preaxial type 1
• Polydactyly syndrome middle ray duplication
• Polydactyly visceral anomalies cleft lip palate

See also

• Syndactyly.
• Dactyly.
• Polydactyl cat.
• Polycephaly = extra head(s).
• Polymelia = extra limb(s).
• Supernumerary body part.
• Antonio Alfonseca, a major league baseball player with polydactylism.
• Anne Boleyn (alleged to have had polydactyly).
• Fabinho, a Brazilian footballer for Toulouse FC with polydactylism.

Polydactyls in Popular Culture

• Hannibal Lector, the fictional psychiatrist and serial murderer, had a sixth finger on his left hand. Its removal is crucial to the plot of the novel Hannibal.
• Swartt and Veil Sixclaw, fictional anthropomorphic ferrets from Brian Jacques's book series, Redwall, were both polydactyls. It was stated in the novel that Veil inherited polydactylism from his father, Swartt.
• Count Rugen, one of the villains in the novel and movie The Princess Bride, had six fingers on his right hand, by which feature Inigo Montoya was able to identify him as the man who'd killed his father.
• Kaleb Carter, the popular pornstar, is a Polydactyly.

External links

• Polydactyly and Syndactyly
• Polydactylism FAQ