Polydactyly

Erin Anderson

What is Polydactyly?

Polydactyly is a condition in which a person or animal has more than five fingers or toes on on one, or on each, hand or foot.It is one of the most common forms of congenital malformation. In the United States, about one in 500 people get polydactyly. Polydactyly is a condition we can inherit if we have a dominant allele of the gene and is a mutation on a speficifc gene on chromosome 7.

Symptoms

Extra fingers or toes (a digit). This digit may be a small, raised bump or a piece of skin that looks like a small finger or toe that isn't fully formed (this is called a nubbin).
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What causes Polydactyly?

GLI3 helps in the patterning of tissues and organs in the development of the embryo by controlling whether specific genes are turned on or off. GLI3 is a transcriptional repressor so it codes for a DNA- binding protein that regulates the expression of one or several genes by decreasing the rate of transcription. Polydactyly follows an autosomal dominant pattern of inheritance so it isn't sex-linked and a child who has a parent with polydactyly has a 50% chance of having it as well.
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There are Two Types of Polydactyly-

  • Isolated Post-Axial: When the extra digits are present on the little toe or finger side of the hand or foot and is more common in African Americans. Mutations are in the 7p13 region of the gene.
  • Pre-axial: This type of polydactyly is common among Asians and the digits are located on the bigger finger or toe side of the hand or foot. Mutations in GLI3 are a bigger cause of pre-axial polydactyly cases.

Ways to Diagnose Polydactyly-

Doctors will examine a patient and examine the extra digit present on the patient. They may take an X-Ray to see if there are any bones present in the digit and may do genetic testing to check their chromosomes and genetic problems.

Treatments of Polydactyly-

  • In a digit with no bone- A vascular clip is attatched to the digit at the base which cuts off blood flow and causes the digit to fall off, a bandage is applied and taken off by a doctor in a future visit.
  • If a digit is better formed surgery is required where a surgeon will carefully cut around bones, ligaments, tendons, etc. to remove the digit.
  • The ethical implications are simple, it is clear when one has polydactyly and you choose if you would like to keep or remove the digit through either surgery or a vascular clip.
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Polydactyly Treatment -

Bibliography-

  • "Polydactyly: MedlinePlus Medical Encyclopedia." U.S National Library of Medicine. U.S. National Library of Medicine, n.d. Web. 20 Mar. 2016.
  • "Polydactyly Study: General Information." Polydactyly Study: General Information. N.p., n.d. Web. 20 Mar. 2016.
  • "Polydactyly of Fingers Symptoms & Causes." | Boston Children's Hospital. N.p., n.d. Web. 20 Mar. 2016.
  • "Polydactyly." Polydactyly. N.p., n.d. Web. 20 Mar. 2016.
  • "Polydactyly (Extra Fingers)." Polydactyly (Extra Fingers). N.p., n.d. Web. 20 Mar. 2016.