Duane Retraction Syndrome 3
Patient Information
Characteristics
Background and History
Duane syndrome is a congenital, non-progressive disorder of eye movement first described by an American ophthalmologist, Alexander Duane, in 1905. It occurs most often as a sporadic, non-familial condition but is sometimes inherited as in this disorder. It is also a part of several syndromes that include anomalies in other parts of the body.
Clinical Correlations
Inherited Duane syndrome when it occurs in the absence of other malformations may be unilateral or bilateral. The essential features are difficulty in moving the eye to the side, and a narrowing of the space between the eyelids when the eye moves toward the nose. The eyes in the majority of individuals do not line up (strabismus) when looking straight ahead and often the patient assumes a head turn to avoid double vision. This is not always effective and about 10% of patients develop a lazy eye (amblyopia). Evidence suggests that the nerves that innervate the eye muscles do not develop normally resulting in weakness of such muscles and difficulty moving the eye in the desired direction. Vision in each eye, however, is normal unless amblyopia develops.
There is considerable clinical variability among individuals. In the disorder described here, as reported in a single family, the abnormal eye movements are usually seen in both eyes. In 3 of 4 individuals there was also documented hearing loss, which occurred in both ears in 1.
Genetics
Inheritance
This is an autosomal dominant condition in which affected parents transmit the causative gene mutation with a 50% probability.
Pedigree
Autosomal dominant
Autosomal dominant disorders require only one mutation for the disease to be expressed. Since an affected parent has two chromosomes, only one of which has the mutant gene, parents can expect that half (50%) of their children will receive that one and inherit the disease. It is common for individuals that inherit the mutation, however, to not have evidence of the disease (nonpenetrance).
Autosomal dominant inheritance leads to a vertical pattern of transmission
Diagnosis and Prognosis
This disorder is usually diagnosed by an ophthalmologist, often during the neonatal period. Because of the variable nature of presentation, no single treatment can be prescribed. In mild cases, prisms in glasses might be sufficient, but for those with a severe head turn or unusual movements of the eyes various surgical treatments can be effective. All children must be followed carefully during the first decade of life since treatment for amblyopia is usually most effective if diagnosed early. Left untreated, the loss of vision and depth perception can become permanent.
There is no impact on longevity.
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