Genomics Final Video, Duane Syndrome

Duane Syndrome

By Casey Olson

Signs and symptoms

How is it treated?

For the majority of patients, DS does not require surgery

Genetics

• Limited horizontal eye movement
• Eyes may be misaligned and point in different directions at all times
• Abnormal head position in an attempt to keep the eyes straight
• Reduced vision in the affected eye
• Eyes may occasionally deviate upward or downward with certain eye movements

However surgery is considered if one wants to:

-reduce strabismus (abonormal alignment of the eyes)

-to eliminate a socially unacceptable head position

-to eliminate a significant upshoot or downshoot

-to eliminate disfiguring enophthalmos ( recession of the eyeball within the orbit)

-Most cases are diagnosed by age 10

-DS may not be apparent until the child grows older and starts to demonstrate difficulty with vision or an abnormal head turn to the side

While most cases of DS usually occur in people with no family history of the disorder, some cases have been shown to have a genetic cause where both dominant and recessive forms have been found

Surgery cannot fix the miswired nerves but can compensate for them by moving the eye muscles; success rate for surgery in eliminating an abnormal head position is estimated to be 79-100%

A pediatric eye specialist can diagnose Duane syndrome by:

-measuring the degree of misalignment in the eyes

-testing the range of movement of both eyes

-determining whether an abnormal head turn is used in an attempt to see better

The exact chromosomal location of the proposed gene for DS is currently unknown, but there have been some links to chromosome 4, 8, and 22, as well as researchers identifying mutations in the CHN1 gene that cause the disorder in a small number of families

What is Duane Syndrome?

DS effects an estimated 1 in 1,000 people worldwide

A rare congenital eye movement disorder

What causes Duane Syndrome?

Believed to be caused by a miswiring of the medial and lateral rectus muscles, which move the eyes

Patients with DS also lack the sixth cranial nerve (abducens nerve)

In 80% of DS cases only one eye is affected, most often the left

Origins of these malfunctions is at present a mystery, although some researchers believe that DS results from a disturbance, either caused by genetic or environmental factors, during embryonic development.

• This condition accounts for 1-5% of all cases of abnormal eye alignment.
• Affects females (60%) more than males (40%)

It also appears to researchers that several factors play a role in causing DS, so it is doubtful that one single mechanism is responsible

Type I: affected eye has limited mobility to move outward toward the ear (78% of all cases)

Type II: eye has limited mobility to move inward toward the nose

(7% of all cases)

Type III: eyes have limited mobility in both areas (15% of all cases)

Living with Duane Syndrome

Many people with DS don't have any symptoms that interfere with their day to day lives

References:

But for those that do, they may suffer from:

-neck pain

-headaches

-loss of vision in the affected eye

Living with any disorder can be difficult; and people with DS must deal with the stigma behind having this disorder.

Although adjusting to this disorder may be a challenge, people living with, for the most part, lead happy healthy lives

-http://www.experienceproject.com/groups/Have-Duane-Syndrome/97737

-https://www.google.com/search?hl=en&authuser=0&site=imghp&

-http://www.childrenshospital.org/cfapps/research/data_admin/Site339/mainpageS339P15.html

-http://www.childrenshospital.org/az/Site3103/mainpageS3103P4.html

-http://omim.org/entry/126800

-http://www.aapos.org/terms/conditions/46

-http://www.genome.gov/11508984

-http://ghr.nlm.nih.gov/condition/isolated-duane-retraction-syndrome