This rare neurodegenerative energy metabolism disease (mitochondrial disease) slowly (subacute) leads to local death of tissue (necrotizing) in the brain, causing the brain to malfunction (encephalopathy). The brain cells don't get enough energy.
Another name for the disease is "Subacute necrotizing encephalopathy".

Up to now, abnormalities have been found in sixty genes in both nuclear and mitrochondrial DNA that cause Leigh syndrome. Mitochondria are actually the brain's energy suppliers. That is why this disease is also called an energy metabolism disease.

Estimates indicate that the disease occurs in about 1 in 40,000 to 100,000 children, both boys and girls starting in the third month of life, but sometimes from the second year of life or even later. There are even adult disease descriptions where this disease begins. In general, the younger the child when the disease manifests, the faster the disease progresses.
Life expectancy varies from five to eight years. It is rare that the teenage age is reached.
Studies are being conducted at Maastricht University to be able to act according to the gene that has been affected. Treatment has so far consisted of suppressing the disease and learning to deal with it (rehabilitation doctor, physiotherapy and occupational therapy, help with nutrition, counseling, social work).

Characteristic is the cognitive and motor deterioration, both in thinking and movement, eventually leading to difficulty breathing. Also disturbed is normal development in rolling over, sitting, standing, walking and learning to talk. On an MRI scan, patients show almost identical symmetrical necrotic scars in the basal ganglia, in the brainstem and in the thalamus, while the other complaints differ from person to person.

Symptoms

• Difficulty moving due to stiff, spastic muscles,
• Difficulty keeping head high due to muscle weakness, including in the rest of the body,
• Jerky movements,
  
• Twisting movements with the arms,
• Abnormal position (dystonia) of the trunk, neck, arms and legs,
• Breathing problems: breathing too fast (hyperventilation), alternating with respiratory arrest (apnea),
  
• Swallowing problems, choking and vomiting,
• Underweight and stunted growth,
• Bad hearing to deafness,
• Bad sight to blindness,
• Shocking eye movements, strabismus or being unable to look to one side,
• Certain manifestations of epilepsy (in arm, leg, head, or trunk),
• Easily overstimulated (sensory, especially sound),
• Irritable, inconsolable,
• Frightened or shy of unfamiliar faces,
• In case of fever, the disease worsens noticeably, precisely because more energy is required which is already insufficiently available,
  
• In case of fever, more lactate gets into the blood, which can be harmful to the kidneys. Lactate is the end product of the glucose metabolism that normally provides energy to skeletal muscles.