Many genes are involved in brain development and function. When changed (mutated) their normal function can be altered resulting in neurological abnormalities. Widespread progressive developmental changes in the brain are sometimes called encephalopathy. The condition described here is a severe form of neurological disease resulting from a specific mutation. Delayed development, epilepsy, and intellectual disability are common features.
Poor eye contact is present from infancy and examination may reveal atrophy (lack of normal development) of the optic nerves that transmit visual signals to the brain.
Infants are floppy (hypotonic) and often have feeding difficulties from birth. Seizures are usually present early in life and often do not respond to treatment. Infants seem to be hyperactive from birth but their movements are usually not purposeful. The general lack of physical and mental development become evident in infancy and many are unable to walk, sit or respond appropriately to their environment. The head appears small and brain imaging may reveal lack of normal brain development.
This condition results from mutations in both copies of a specific gene. Individuals such as the parents who carry a single mutated copy are clinically normal but each of their children has a 25% risk of inheriting the two abnormal copies.
There are no diagnostic physical signs. Pediatricians, neurologists, and ophthalmologists can collaborate on the diagnosis and care. Laboratory studies such as MRIs and gene determinations can be helpful to the diagnosis. No treatment has been reported and most individuals require supportive care since they are unable to sit, walk, or speak. Nothing is known regarding longevity.