Polydactyly

Polydactyly

Symptoms

• Extra Digit on hand
• Extra Digit on foot
• The extra 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 (nubbin).
• A complete, working finger or toe.
• This is considered a non-syndromic anomaly.

Further Genetics

• The cause is genetic, in particular, mutations on a specific gene on chromosome 7, and it can occur in generations of families.
• One gene that can cause Polydactyly is GLI3, and it is one of a number of genes that are known to be involved in the patterning of tissues and organs during development of the embryo.

Prevention

• Polydactyly is an inherited disease, and cannot be prevented.
• Surgery is recommended during early ages to stop any further abnormalities.

Types of Polydactyly

Definition:

• Isolated post-axial polydactyly - which is more common amongst African-Americans and is where the extra digits are located on the small digit side (little finger, little toe) of the hand or foot.
• The mutations are located in the 7p13 region of the gene.
• Pre-axial polydactyly - is more common amongst Asian populations and is where the extra digits are located on the large digit side (thumb/big toe) of the hand or foot.
• The genetics here are not as clearly defined as post-axial polydactyly, but it is more likely to occur with other congenital abnormalities such as the fusion of skin between some fingers and toes.

Causes and treatments

• The condition of having more than the normal number of toes or fingers—called also polydactylia, polydactylism
• Polydactyly often occurs bilaterally (on both hands or both feet), or it may occur on just one hand or foot. Similarly, a person may have extra digits on just the hands, just the feet, or some other combination.
• There are over 30 rare congenital syndromes in which Polydactyly is present.
• Polydactyly follows an autosomal dominant pattern of inheritance which means that 1) it is not sex-linked, so that boys and girls may be equally affected and 2) a child who has a polydactyl parent has a 50% chance of being polydactyl too.

Treatments

Causes

• Surgical treatment consists of excision of the duplicated digit and reconstruction of any associated abnormalities
• The main decision is to decide whether or not to do anything for the problem. Certain types of polydactyly are associated with other birth related problems elsewhere in the body, and it is a good idea to have an evaluation for this reason alone. Surgery for polydactyly is usually best done in the first few years of life so that the look, feel and function of the corrected hand is the most natural for the child.

• The trait may be passed down in families as an isolated, benign condition, like having a hitchhiker's thumb or being double jointed.
• Polydactyly occurs when the body follows a different set of directions than usual while forming the hands or feet during development.
• Alternatively, the trait may exist as part of a syndrome, which is a group of several recognizable clinical features that often occur together.

Side Effects of the Disease and the Treatments

• Someone with Polydactyly isn't effected by disease.
• Generally, the digit that is best aligned with the long bones is saved. When the other digit is removed, sometimes transferring tendons from the amputated digit will make the one that remains more normal. Sometimes a joint needs to be reconstructed, or a bony prominence shaved.

Work Cited

• Merriam-Webster. Merriam-Webster. Web. 9 Feb. 2015. <http://www.merriam-webster.com/dictionary/polydactyly>.
• "Polydactyly Symptoms and Diagnosis." Polydactyly Symptoms and Diagnosis. Web. 9 Feb. 2015. <http://www.seattlechildrens.org/medical-conditions/bone-joint-muscle-conditions/polydactyly-symptoms/>.
• "Symptoms of Polydactyly." - RightDiagnosis.com. Web. 9 Feb. 2015. <http://www.rightdiagnosis.com/p/polydactyly/symptoms.htm>.
• "Polydactyly Study: General Information." Polydactyly Study: General Information. 2 Apr. 2012. Web. 9 Feb. 2015. <http://www.genome.gov/27529688>.
• "Polydactyly (Extra Fingers)." Polydactyly (Extra Fingers). Web. 9 Feb. 2015. <http://www.eatonhand.com/hw/hw024.htm>.
• "Polydactyly." Genetic Disorder Research -. Web. 9 Feb. 2015. <https://runkle-science.wikispaces.com/Polydactyly>.
• Author not listed."Polydactyly".University of Maryland Medical Center. 5/9/07.http://www.umm.edu/ency/article/003176.htm.
• 2.Author not listed."Polydactyly(Extra Fingers)".Handworld. 5/9/07.http://www.eatonhand.com/hw/hw024.htm.
• 3.Author not listed."Polydactyly and Syndactyly".Penn State Milton S. Hershey Medical Center College of Medecine.5/14/07.http://www.hmc.psu.edu/healthinfo/pq/poly.htm
• 4.Suzan Grindell."What is Polydactyly?".Maine Coon Polydactyls.5/8/07.http://homepages.ihug.co.nz/~grins/polydactylmainecoons/page2.html
• Green, Dr. Alan. "Polydactyly – DrGreene.com." DrGreene.com. 19 May 1997. Web. 9 Feb. 2015. <http://www.drgreene.com/qa-articles/polydactyly/>.
• "Polydactyly." Polydactyly. Web. 9 Feb. 2015. <http://www.healthcentral.com/ency/408/003176.html>.
• Arnold, Paul. "What Causes Polydactyly? The Inheritance of Polydactyly and the Gene That Causes It." Bright Hub. Bright Hub Inc., 29 Aug. 2009. Web. 9 Feb. 2015. <http://www.brighthub.com/science/genetics/articles/47390.aspx>.
• "Teaching Resources." Division of Genetics and Metabolism. 1 Jan. 2004. Web. 9 Feb. 2015. <https://www.peds.ufl.edu/divisions/genetics/teaching/hand_malformations.htm>.

Jaide Wendt

Mrs.Christman

Biology B

January 29, 2015