Explaining Mitochondrial Disease

Mitochondrial disease is a broad term that covers a wide range of mitochondrial disorders and syndromes.

There are hundreds of diseases associated with mitochondrial disease. Symptoms affect everyone differently and can vary from mild to life-threatening. Younger people tend to have more debilitating conditions.

Most people with a mitochondrial disease experience symptoms that affect multiple systems at the same time. Common symptoms are grouped together and referred to as syndromes. Mitochondrial disease is divided into two distinct categories – primary mitochondrial disease and secondary mitochondrial dysfunction. The distinction is important as each has a unique genetic basis, diagnosis and treatment strategies.

The two most common symptoms of mitochondrial disease are muscle weakness and exercise intolerance that leads to unusual feelings of exhaustion. People with mitochondrial diseases often have symptoms affecting three or more organs like the brain, nerves, heart, pancreas, liver, eyes, and kidneys which have high energy needs.

Mitochondrial diseases are broken into two main groups:

Primary Mitochondrial Disease occurs when changes, known as mutations, are identified in the genes of our mitochondrial responsible for creating energy (ATP). These conditions are inherited.

Secondary Mitochondrial Dysfunction causes similar mitochondrial dysfunction but the mutations occur in genes not involved in energy production. These conditions can be inherited or develop as a result of production of specific proteins, oxidative stress, harmful drugs or environmental factors.

Mitochondrial disease is difficult to diagnose and treat because it affects different people in different ways, can be inherited or acquired, is not well-known by the public or healthcare community, and there is no single, definitive test.