Duane S Syndrome

Duane’s Syndrome

Duane’s Syndrome is a congenital defect. Eye muscle abnormality characterized by inability to move one eye outward past the midline (abduction) and retraction of that eye into the orbit, with narrowing of the eyelid fissure on attempted movement of that eye toward the nose (adduction). Duane’s Syndrome is often accompanied by esotropia (inward eye deviation).

Other names for this condition include: Duane's Retraction Syndrome (or DR syndrome), Eye Retraction Syndrome, Retraction Syndrome, Congenital retraction syndrome and Stilling-Turk-Duane Syndrome.

Parts of the visual system affected:

The cranial nerve is missing, and there is no cure for Duane Syndrome.

Common Treatments:

The majority of patients remain symptom free and able to maintain binocularity with only a slight face turn. Duane syndrome cannot be cured, as the “missing” cranial nerve cannot be replaced and, traditionally there has been no expectation that surgery will result in any increase in the range of eye movement. Surgical intervention, therefore, is recommended where the patient is unable to maintain binocularity, or where they are forced to adopt a cosmetically unsightly or uncomfortable head posture in order to maintain binocularity. The aims of surgery are to place the eye in a more central position and, thus, place the field of binocularity more centrally also, and to overcome or reduce the need for the adoption of an abnormal head posture. Occasionally surgery is not needed during childhood, but becomes appropriate later in life, as head position changes (presumably due to progressive muscle contracture).

Functional implications of the condition

DS is a miswiring of the eye muscles that causes some eye muscles to contract when they should not and other eye muscles not to contract when they should. People with DS have a limited and sometimes absent ability to move their eye outward toward the ear (ie, abduction), and in most cases, they have a limited ability to move the eye inward toward the nose (ie, adduction).

In most patients, DS is diagnosed by the age of 10 years. This probably occurs around the sixth week of pregnancy and is due to poor development of tiny parts of the brainstem that control the eye muscles. In DS, the sixth cranial nerve that controls the lateral rectus muscle (the muscle that rotates the eye out toward the ear) does not develop properly. Why the nerve does not develop is not yet understood. Thus, the problem is not primarily with the eye muscle itself but with the nerve that transmits the electrical impulses to the muscle. There is also irregular innervation of a branch from the third cranial nerve, which controls the medial rectus muscle (the muscle that rotates the eye toward the nose). This is why abnormalities may be found in both left gaze and right gaze.

DS is an inability to move an eye laterally away from the nose with widening of the eyes (palpebral fissure), retraction of the eye when attempting to look close or towards ones nose; and retraction of the eye.

Facts:

Around 10-20% of DS cases are familial; these are more likely to be bilateral than non-familial Duane syndrome. Duane syndrome has no particular race predilection. While usually isolated to the eye abnormalities, Duane syndrome can be associated with extraocular problems (so-called "Duane's Plus"), including cervical spine abnormalities

Most patients are diagnosed by the age of 10 years and DS is more common in girls (60 percent of the cases) than boys (40 percent of the cases).

References:

1. Dictionary of Eye Terminology 5th Edition. Barbara Cassin, Melvin L. Rubin, MD, Editor. Pg 93
2. Engle E. The genetics of strabismus: Duane, Moebius and fibrosis syndromes. In: Traboulsi E (ed) Genetic Diseases of the Eye: a Textbook and Atlas. Mosby, St. Louis, p 477-512.1998
3. Localization of a gene for Duane retraction syndrome to chromosome 2q31. Am J Hum Genet.1999