Duane-Radial Ray Syndrome
Patient Information
Characteristics
Background and History
This is a malformation syndrome with skeletal, ocular, and kidney abnormalities. It was recognized at the end of the 20th century and is sometimes called Okihiro syndrome.
Clinical Correlations
There is considerable variation in the clinical features. Most patients have some anomalies of the hands, fingers, toes, and kidneys. There may be fusion of the fingers, extra fingers or even missing ones. The thumb is most frequently involved and maybe missing or underdeveloped. Sometimes the bones in the forearms are missing as well. There is often some hearing loss with evident malformation of the ears. The kidneys may be malformed or dislocated.
The eyes often do not move normally but in a pattern often called Duane syndrome in which crossing of the eyes can be evident. However, vision is often poor because of maldevelopment of the optic nerve and the retina. The eyes can appear abnormally small and seem spaced too far apart.
Genetics
Inheritance
This is an autosomal dominant condition in which the malformations are passed directly from one generation to the next. Children of an affected parent have a 50% chance of inheriting the same condition.
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
A pediatrician or orthopedist is most likely to make the diagnosis based on the skeletal abnormalities. The eye problems should be fully defined by an ophthalmologist. The health of the kidneys should be evaluated by a renal specialist. Life expectancy is likely normal.
No treatment is available for this condition but it may be possible to do reconstructive surgery on the hands to improve function. The crossing of the eyes may improve with surgery but this is seldom required. Low vision aids may improve visual function.
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