Nystagmus 3, Congenital, AD
Patient Information
Characteristics
Background and History
Nystagmus (sometimes called ‘dancing eyes’) in all its forms has been known since antiquity. It is a type of bilateral involuntary eye movement disorder usually manifest as a slow movement in one direction and a rapid motion in the other direction. It is present physiologically in everyone to a minor degree under certain conditions but it is often pathologic when exaggerated movements are present. Movements may be in any direction but usually the motion is horizontal. Since the eye cannot fixate steadily, vision is reduced to some degree in most individuals.
Clinical Correlations
This condition can be present at birth and vision is minimally impacted. Only two families have been reported and the full clinical features are unknown. No systemic health problems have been reported.
Genetics
Inheritance
In the reported families, nystagmus followed a vertical pattern typical of autosomal dominant inheritance. Members of both sexes can be affected and affected parents can expect that half of their children will inherit 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
Pediatricians are most likely to make the diagnosis and ophthalmologists can confirm the diagnosis. Longevity is not impacted. Glasses, contact lenses, and sometimes eye muscle surgery can sometimes reduce the amount of eye shaking. No cure is available but individuals can benefit from low vision aids and devices.
Since other disorders may coexist it is important to rule out causative neurologic and eye diseases which may be treatable.
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