This is a rare hereditary neurodegenerative condition in which there is an early-onset of brain and neurological damage with blindness, hearing loss, and seizures. It was first described in the 1980s.
Most infants seem to develop normally in the first year of life but by 10-18 months of age muscle weakness and coordination difficulties appear. Youngsters seem ‘floppy’ and often slow purposeless movements are seen in the arms and in the face. Muscle dysfunction and weakness progress relentlessly and many patients are confined to wheelchairs by their teenage years. There is also a more severe form in which associated liver disease leads to death within 5 years. Hearing loss and seizures are part of the syndrome and many individuals experience profound deafness. The sense of touch may be diminished.
Abnormalities of eye movements with some degree of difficulty moving the eyes (ophthalmoplegia) become evident at some point in the first decade of life. At the same time, damage to the optic nerve (connecting the eye to the brain) may become evident leading to severe vision loss.
This is an autosomal recessive condition requiring changes (mutations) in two copies of a gene. Both clinically normal parents carry one copy of the mutation and in one out of four pregnancies on average the child inherits both copies and expresses this disorder.
A neurologist or pediatrician is most likely to make this diagnosis, often with the collaboration of an ophthalmologist who notes the abnormal eye movements and the optic nerve damage. There is no effective treatment.
Mildly affected individuals can live to young adulthood whereas those with more severe disease may not live beyond childhood. Mobility aids and physical therapy could aid in minimizing ambulatory difficulties while assistive hearing devices and low vision aids early could be helpful for sensory stimulation.