Leigh Syndrome

What is Leigh syndrome?

Leigh syndrome is a neurological disorder that is characterized by the loss of mental and motor abilities. The onset of this condition is typically during infancy, but some may see the onset during adulthood. 

One in every 40,000 newborns are affected by Leigh syndrome, but it is more common within specific populations, such as certain regions of Quebec and the Faroe Islands. 

What are the symptoms of Leigh syndrome?

The onset of symptoms typically occurs during infancy. Parents or doctors will notice that a child is having issues with swallowing, vomiting, and has diarrhea. All of these things will lead to a failure to thrive. 

Later symptoms include weak muscle tone, dystonia, and ataxia. Those affected may also lose sensation in their limbs, which makes movement difficult. Additional symptoms include:

• Paralysis of the muscles that move the eyes
• Rapid eye movements
• Degeneration of the nerves that carry information from the eyes to the brain
• Severe breathing issues
• Hypertrophic cardiomyopathy
• Lactate buildup

What causes Leigh syndrome?

More than 75 genes can have mutations that result in Leigh syndrome. Some of these genes cause issues in nuclear DNA while others result in mutations within the mitochondrial DNA. The similarity between these mutations is that they all affect the energy production in the mitochondria. Decreased energy can lead to cell death, which may cause the characteristic symptoms. 

Due to the myriad of genes that can cause this syndrome, there are multiple inheritance patterns. The majority of cases are passed down in an autosomal recessive pattern, while others are inherited in a mitochondrial pattern. The minority of cases occur in an X-linked recessive pattern. 

How is Leigh syndrome diagnosed?

A clinical examination is the first step in a diagnosis, which is followed by multiple tests. These tests include MRIs, CT scans, and blood tests. 

What are the treatments for Leigh syndrome?

There is no cure for Leigh syndrome; treatment is symptomatic. A team of specialists may be necessary to treat the various symptoms. 

Thiamine or thiamine derivatives are the most common treatment. It has been shown to slightly slow the progression of symptoms. A certain diet, high in fat and low in carbohydrates, has also been shown to positively impact Leigh syndrome patients. 

Where can I find out more about Leigh syndrome?

• • NIH
  • NORD
  • United Mitochondrial Disease Foundation