Children with Leigh syndrome (Leigh’s disease) inherit a gene or mitochondrial change that causes nervous system cells to die. This rare mitochondrial disease causes seizures, developmental delays, heart issues and breathing difficulties. It sometimes affects adults. Treatments can ease symptoms, but there isn’t a cure for this fatal condition.
Leigh syndrome (also called Leigh’s disease) is a rare genetic condition that affects your child’s central nervous system. A newborn with Leigh syndrome seems healthy at birth. Over time, cells in their nervous system break down or degenerate. Symptoms, such as feeding problems, seizures and continuous crying, tend to occur when your child is between 3 months and 2 years old.
An inherited gene change (mutation) causes Leigh syndrome. It’s a type of mitochondrial disease. Unfortunately, there isn’t a cure. The condition is fatal, with most children passing away by age 3. In rare instances, the condition develops during adolescence or adulthood.
Mitochondria are your body’s energy factories. These tiny cellular structures convert the energy in fatty acids and glucose into a substance called adenosine triphosphate (ATP). This substance energizes cells.
All cells (except red blood cells) have mitochondria. Mitochondrial diseases occur when mitochondria don’t function as they should. As the energy output of cells diminishes, cell damage or death occurs. Your nervous system requires a lot of energy to function. Leigh syndrome damages or destroys cells in your child’s nervous system that provide energy to their brain, nerves and spinal cord.
Leigh syndrome gets its name from British physician Archibald Denis Leigh, who first described the condition in 1951. He called the condition subacute necrotizing encephalomyelopathy (SNE). Encephalomyelopathy refers to diseases that affect the brain and spinal cord. Today, most healthcare providers use Leigh syndrome or Leigh’s disease when talking about this condition.
The types of Leigh syndrome include:
Classic (early-onset) Leigh syndrome affects approximately 1 in 40,000 newborns worldwide. Experts aren’t sure why certain geographic populations are more at risk for Leigh syndrome.
The condition affects:
Experts have identified mutations in more than 75 different genes that can cause Leigh syndrome. The gene mutations affect your body’s ability to make ATP.
An estimated 8 in 10 children with Leigh syndrome inherit the gene change that causes the condition through one of two ways:
About 2 in 10 children inherit a change in mitochondrial DNA (mtDNA) from their mothers. Both boys and girls can inherit this gene change, which then can affect every generation of a family. Rarely, a spontaneous mtDNA mutation occurs. The most common mtDNA change in Leigh syndrome keeps the MT-ATP6 gene from making ATP.
Symptoms of Leigh syndrome typically appear within your infant’s first two years of life. At first, your baby may reach expected child development milestones like holding up their head. Then, they start to regress, losing these abilities or showing signs of physical or developmental delays.
Signs of early-onset Leigh syndrome include:
Other symptoms may occur as the disease progresses. These symptoms can also appear with late-onset Leigh’s disease, including:
Leigh syndrome can also affect eye nerves, leading to problems like:
Leigh syndrome can lead to a buildup of lactic acid in your child’s bloodstream, causing lactic acidosis. Your body makes lactic acid when oxygen levels in cells get too low to aid metabolism (the breakdown of carbohydrates into energy). There may also be too much carbon dioxide in their blood.
Lactic acidosis and increased levels of carbon dioxide can lead to:
Your healthcare provider may order:
There isn’t a cure for Leigh syndrome. Treatments focus on easing symptoms to keep your child comfortable. Unfortunately, the condition is fatal.
Your child may benefit from:
Children with certain enzyme deficiencies may benefit from a high-fat, low-carbohydrate diet. Some children who struggle to eat may need tube feeding (enteral nutrition).
If you have a child with Leigh syndrome, a genetic test can determine if you or your partner have a gene mutation that causes it. You may decide to meet with a genetic counselor to discuss ways to lower the risk of passing along the mutated gene to future generations.
Many children with Leigh syndrome pass away from respiratory failure by age 3. It’s rare for a child with early-onset Leigh syndrome to survive into their teen years. People with adult-onset Leigh syndrome can live past their 50s.
Call your child’s healthcare provider if your child has:
You may want to ask your healthcare provider:
A note from Cleveland Clinic
When your child has a rare life-limiting illness, it’s helpful to seek care from experts familiar with the disease. Leigh syndrome can affect various parts of your child’s body, such as their brain, eyes and organs, like their heart and kidneys. You may need to see multiple specialists. These providers can help manage symptoms and connect you with supportive resources so you can enjoy your time with your child.
Last reviewed by a Cleveland Clinic medical professional on 08/13/2022.
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