OMIM ID:
Nystagmus 4, AD
Alternate Names
Defective Genes
Clinical Characteristics
Ocular Features
Abnormal eye movements generally are present as early as 1 to 2 years of life and are stable but they are not congenital in origin. Eye movement anomalies are somewhat variable and unusual with gaze-paretic nystagmus and poor or absent smooth pursuit most common. The nystagmus may also be upbeat in direction. A poor vestibuloocular reflex might be part of this eye movement complex. Vision in many individuals is normal but mildly decreased in others. Strabismus (primarily esotropia and exophoria) is common.
Systemic Features
Mild “balance problems” have been reported by some patients. One individual reported intermittent dizziness. No other cerebellar signs are present. Neuroimaging found no CNS abnormalities in one patient. Seizures and ataxia were separately reported in two persons.
Genetics
Inheritance
The single reported family shows a transmission pattern consistent with autosomal dominant inheritance. A locus cosegregating with the condition has been found at 13q31-q33 but no specific mutation has been identified.
Only one family has been reported and additional information is needed to document the uniqueness of this disorder.
Other autosomal dominant congenital nystagmus conditions in this database are: NYS2, NYS3, and NYS7.
Three X-linked isolated congenital nystagmus conditions may also be found in this database: NYS1, NYS5, and NYS6.
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