Polydactyly

From Wikipedia, the free encyclopedia

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.

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. 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^[2] 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

[edit] 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

Please help improve this section by expanding it. Further information might be found on the talk page or at requests for expansion.

[edit] Real polydactyls

• Hrithik Roshan, a Bollywood actor born with a supernumerary thumb on his right hand.^[3]
• Antonio Alfonseca, a Major League Baseball pitcher
• It is commonly believed that Anne Boleyn, second wife of Henry VIII, had this disorder.
• Norwegian Lundehund^[4]
• Polydactyl cats
• Little Tich

[edit] Mythological and fictional polydactyls

This section does not cite any references or sources. (April 2008) Please help improve this section by adding citations to reliable sources. Unverifiable material may be challenged and removed.

• Hannibal Lecter, 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 had killed his father. Also, this made finding a good sword difficult for the count.
• There is a biblical giant said to have had six fingers on each hand and six toes on each foot:

  2 Samuel 21:20

  And there was yet a battle in Gath, where was a man of great stature, that had on every hand six fingers, and on every foot six toes, four and twenty in number; and he also was born to the giant. - KJV

  1 Chronicles 20:6

  And yet again there was war at Gath, where was a man of great stature, whose fingers and toes were four and twenty, six on each hand, and six on each foot and he also was the son of the giant. - KJV

[edit] See also

• Syndactyly
• Dactyly
• Polydactyl cat
• Polycephaly = extra head(s)
• Polymelia = extra limb(s)
• Supernumerary body part

[edit] References