Mitochondrial diseases are rare genetic conditions that affect how the body produces energy. Around 1 in every 5,000 children is born with a mitochondrial disease. These conditions are caused by changes in genes that can be inherited from either parent through nuclear DNA, or from the mother through mitochondrial DNA.
Mitochondria are tiny structures found in almost every cell in the body. They convert the nutrients from food into the energy our bodies need to work properly. They are often described as the body’s “power stations” or “batteries”.
In people with mitochondrial disease, these batteries do not work properly. As a result, the body’s cells and organs do not get enough energy. This particularly affects organs that need a lot of energy, such as the brain, muscles, and heart.
There are more than 300 different types of mitochondrial disease. Symptoms vary widely depending on which parts of the body are affected.
Leigh Syndrome
Ellie was diagnosed with Leigh Syndrome, a severe form of mitochondrial disease.
In Leigh Syndrome, most of the body’s mitochondria do not work properly. This has a major impact on brain development and function. Children with Leigh Syndrome often struggle to reach developmental milestones and may gradually lose abilities they had previously developed, such as sitting, moving, kicking their legs, or even crying.
One of the earliest signs of Leigh Syndrome is often difficulty with feeding. Babies may have problems swallowing, frequent vomiting, or reflux-like symptoms. Because feeding can be difficult, children may not gain weight or grow as expected, a problem doctors call “failure to thrive.”
Other common symptoms include:
- Muscle weakness
- Problems with movement and coordination
- Involuntary muscle movements
- Reduced sensation in the arms or legs
- Seizures
- Vision problems
People with Leigh Syndrome often have high levels of a substance called lactate in their bodies. This can affect breathing, kidney function, movement, and development.
Symptoms usually begin before a child’s first birthday. The condition gradually worsens over time. Sadly, many children with Leigh Syndrome do not live beyond early childhood, most commonly because of serious breathing problems.
Children with Leigh Syndrome are particularly vulnerable to infections and viruses. Their bodies may not have enough energy reserves to fight illness while also carrying out essential daily functions.
Although symptoms usually begin in infancy, in rare cases Leigh Syndrome can develop during adolescence or adulthood.
Treatment and support
There is currently no cure for Leigh Syndrome. Treatment focuses on managing symptoms and supporting the child’s quality of life.
Children may receive help from dietitians, feeding specialists, and speech and language therapists to manage feeding difficulties. Some may need a feeding tube.
Physiotherapy, occupational therapy, and specialist equipment such as supportive seating or adapted prams can help with movement and muscle weakness. Some people are also prescribed vitamins, particularly B vitamins.
NARP Disease
During Ellie’s diagnostic testing, doctors discovered that her mother also has a mitochondrial condition, although it affects her much less severely.
She was diagnosed with NARP disease, which stands for Neuropathy, Ataxia and Retinitis Pigmentosa. Around 65% of her mitochondria are affected, compared with a much higher proportion in Ellie.
For much of her life, Ellie’s mother had very few symptoms, apart from severe migraines.
Regular eye examinations have shown gradual damage to the light-sensitive cells in her eyes, a condition known as retinitis pigmentosa. As a result, she has recently stopped driving at night and may experience more significant vision loss in the future.
She also experiences nerve-related symptoms (neuropathy), including pain, tingling, and numbness in her hands, arms, feet, and legs. She takes medication to help manage these symptoms. At times, she also has problems with balance and coordination (ataxia).
People with NARP can be at increased risk of other health conditions, including dementia, heart disease, diabetes, and hearing loss. Because of this, Ellie’s mother has regular health checks.
More recently, she has entered perimenopause, which has worsened some of her mitochondrial symptoms. Changes in estrogen levels during menopause can affect mitochondrial function, leading to episodes of severe muscle weakness and mental fatigue.
Ellie Mae's Legacy 