Duane syndrome

Duane  is a disorder of eye movement. This condition prevents outward movement of the eye (toward the ear), and in some cases may also limit inward eye movement (toward the nose). As the eye moves inward, the eyelids partially close and the eyeball pulls back (retracts) into its socket. Usually only one eye is affected. Some people with Duane syndrome develop amblyopia ("lazy eye"), a condition that causes vision loss in the affected eye. Most cases occur without other signs and symptoms. There are three forms of Duane syndrome, designated types 1, 2, and 3. The types vary in which eye movements are most severely restricted (inward, outward, or both). All three types are characterized by retraction of the eyeball as the eye moves inward and are  in an  fashion.

Symptoms

Duane  (DS) is present at birth and is characterized by limitation of horizontal eye movement (a limited ability to move the eye inward toward the nose (adduction), outward toward the ear (abduction), or in both directions). In addition, during adduction, the eyeball pulls in and the eye opening (palpebral fissure) narrows. In some cases, when the eye attempts to look inward, it moves upward or downward. Duane syndrome has 3 sub-types which vary depending on which type of eye movement is most restricted.

In Duane syndrome type 1, abduction is limited, but adduction is normal or close to normal. The eye opening narrows and the eyeball retracts into the orbit during adduction, and the reverse occurs during abduction. In Duane syndrome type 2, adduction is limited, and abduction is normal or only slightly limited. In Duane syndrome type 3, both adduction and abduction are limited. The eyeball retracts during adduction in types 2 and 3. Each of these three types has been further classified into three subgroups designated A, B, and C to describe the eyes when looking straight.

Duane syndrome is an isolated finding in approximately 70 percent of cases but may be associated with other abnormalities. Major anomalies that may be associated with DS may affect the skeletal system, ears, eyes, nervous system, and/or the kidneys and urinary tract.

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Medical Terms	Other Names	Learn More: HPO ID
80%-99% of people have these symptoms
Oculomotor nerve palsy		0012246
Short palpebral fissure	Short opening between the eyelids	0012745
	Cross-eyed [ more  ]	0000486
30%-79% of people have these symptoms
Abnormal vertebral segmentation and fusion		0005640
Anteverted nares	Nasal tip, upturned [ more  ]	0000463

Cause

Given the evidence that Duane  (DS) results from an absence of the abducens nerve (cranial nerve VI) and aberrant innervation, and that it is associated with other anomalies in some cases, it is thought to result from a disturbance of normal embryonic development by either a genetic or an  at the time when the cranial nerves and ocular muscles are developing (between the third and sixth week of pregnancy). Genetic studies of two large families with DS  autosomal dominantly (without associated abnormalities) established that  in the CHN1  were found to be the cause in these and several other families.

Duane-radial ray syndrome (DRRS), inherited in an  manner, has been shown to be caused by mutations in the SALL4 gene. However, no SALL4 gene mutations were found in 25 sporadic cases of isolated DS (occurring in one individual in a family with no additional abnormalities).

DS can also be found as part of another complex  disorder (that can include deafness, facial weakness, vascular malformations and leaning difficulties) due to mutations in the HOXA1 gene. In addition,  studies of individuals with DS and other abnormalities have, in rare cases, shown abnormalities that suggest other locations for genes responsible for causing DS.

Inheritance

The majority of cases of Duane  are sporadic (occurring in individuals with no history of the condition in the family). About 10% of affected individuals appear to have other affected family members. Both  (most commonly) and  forms of Duane syndrome have been documented. In some families with dominant Duane syndrome, it has appeared to "skip a generation" (showing ) and it has also been shown to range in severity within the same family (showing ).[3] Most  cases are not associated with other anomalies. Given the large percentage of sporadic cases, it seems likely that both genetic and  play a role in the development of Duane syndrome amongst affected individuals.

Treatment

The treatment of Duane  may involve surgery. The goal of surgery is to eliminate or improve head turn, eliminate or reduce significant misalignment of the eyes, reduce severe retraction (when they eyeball pulls into the socket as the eye moves toward the nose), and improve upshoots and downshoots (when the eye deviates upward or downward with certain eye movements). No specific surgical technique has been completely successful in eliminating the abnormal eye movements. However, some procedures, used either alone or in combination, may be successful in improving or eliminating head turns and misalignment of the eyes. The choice of procedure varies among affected individuals. The success rate for surgery in eliminating an abnormal head position is estimated to be 79-100%.[6]

The management of Duane syndrome without surgery may include:[6]

• special seating in school to accommodate a child's head turn
• special rear-view mirrors to help during driving
• a prism placed on the individual's glasses to correct for the face turn (though this is not commonly used)
• vision therapy to treat secondary convergence insufficiency (inability of the eyes to turn towards each other or sustain this position)

More detailed information about the treatment of Duane syndrome is available on Medscape Reference's Web site and can be viewed here. You may need to register to view this information, but registration is free.

Organizations

Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

• Yahoo! Duane Syndrome Online Support Group Website: https://groups.yahoo.com/neo/groups/duanes/info

Learn More

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

• The American Association for Pediatric Ophthalmology and Strabismus provides a patient information sheet on Duane syndrome. Click on the link to view this information.
• Genetics Home Reference (GHR) contains information on Duane syndrome. This website is maintained by the National Library of Medicine.
• The National Human Genome Research Institute's (NHGRI) website has an information page on this topic. NHGRI is part of the National Institutes of Health and supports research on the structure and function of the human genome and its role in health and disease.
• The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.

In-Depth Information

• GeneReviews provides current, expert-authored, peer-reviewed, full-text articles describing the application of genetic testing to the diagnosis, management, and genetic counseling of patients with specific inherited conditions.
• Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
• The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
• Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
• PubMed is a searchable database of medical literature and lists journal articles that discuss Duane syndrome. Click on the link to view a sample search on this topic.

Duane syndrome Resources
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