This is a recently reported, progressive, hereditary, degenerative disorder of the brain.
Most symptoms are first evident late in the first decade or early in the second of life. Gait difficulties such as unsteadiness are among the first symptoms but other features such as slurred speech, cognitive decline, purposeless movements of the limbs, and signs of Parkinsonism are detected soon. Some patients have a mild hearing loss. Imaging of the brain reveal some loss of tissue in selected areas. Urinary incontinence has been reported. Many individuals are wheelchair-bound in later life.
Eye movements may be abnormal with jerkiness and limited upgaze. Patients may have difficulty following visual targets and use exaggerated head motions to do this.
Only a few patients have been reported and molecular studies reveal two mutations in a specific gene, consistent with autosomal recessive inheritance. The parents, who both carry one copy of the mutation, are clinically normal but confer a 25% risk for this condition to each of their children.
It is unlikely that this condition will be diagnosed in newborns since there are no outward physical signs. Neurologists are the most likely to detect this disorder but probably not until late in the first decade of life. No treatment has been reported but physical therapy might be helpful to preserve mobility.
Nothing is known regarding longevity.