This is one of several hereditary, nonprogressive forms of strabismus (abnormal alignment of the eyes) in which the eye movements are restricted. Although the name implies a disease of the muscles that move the eye, the primary disorder is usually one of maldevelopment of the nerves that supplies those muscles.
A single family with a combination of restricted eye movements and hand malformations has been reported. This is a congenital and non-progressive malformation disorder. The right eye is primarily involved and usually is deviated laterally and unable to look up. The right eye lid droops in some patients and they are unable to elevate it. Vision is normal unless a lazy eye (amblyopia) develops.
There are also abnormalities of the fingers and wrists, again mainly involving the right side. The 5th and sometimes also the 4th fingers may be absent. Often the small bones of the right wrist are missing or malformed. Sometimes the 4th and 5th fingers appear to be fused.
No mutation has been found to be responsible. However, a location on chromosome 21 seems to contain a DNA abnormality in all patients suggesting a genetic cause. In addition there is consanguinity among the parents of affected children in the large Turkish kindred reported suggesting that this is likely an autosomal recessive disorder requiring two copies of the mutation to cause disease. The parents with one copy would be carriers and therefore have a 25% risk that each child could inherit the disorder.
This disorder might be diagnosed by an ophthalmologist in consultation with a medical geneticist. It has no impact on longevity nor is treatment required. However, some cosmetic improvement is possible with eye muscle and eyelid surgery. Amblyopia (lazy eye) should be appropriately treated.