Many genes are involved in brain development and function. When changed (mutated) their normal function can be altered resulting in neurological abnormalities. Widespread changes in the brain are sometimes called encephalopathy. The condition described here is a severe and lethal form of neurological disease resulting from a specific mutation. Delayed development, visual impairment, epilepsy, and mental retardation are common features.
This is a relentlessly progressive condition. Seizures often have their onset within a few days or weeks after birth and become intractable to pharmacologic treatment. Infants do not make eye contact and they may lack the usual visual responses to environmental stimuli. The optic nerves show evidence of damage.
Infants do not move properly and do not display the appropriate responses to handling and external stimuli. The limbs are usually 'floppy'. Developmental milestones such as sitting, head-holding, and crawling are not achieved. They never learn to walk or speak and have feeding difficulties. Brain scans (MRIs), although normal early, later show lack of development or regression in certain structures.
This condition has been reported in two sibs, each of which carry a mutation in the same specific gene. The parents, however, did not carry the mutation in body cells suggesting that one of them has a change in germ (reproductive) cells.
Since infants appear normal at birth, the diagnosis is most likely made at some point in the first month of life when seizures occur. The diagnosis would likely be made by collaboration among pediatricians and neurologists. The condition is progressive and the two reported infants died at 3.5 and 7 years of age.
There is no treatment for the general condition and complete supportive care is required. Seizures do not respond to the usual antiepileptic medications. Feeding tubes may be required to maintain nutrition.