"...any disease, any organ, any age…”
Energy is essential for the function of all organs. Cells with high energy needs often contain more mitochondria. The mitochondrial metabolism requires a broad variety of chemical reactions involving hundredths of enzymes which must work almost perfectly in order to ensure a continuous supply of energy. When the mitochondria aren't functioning properly, an "energy crisis" can develop in tissues such as muscle, brain and heart, which normally are heavy energy consumers. The severity of the disease depends on the residual enzyme activity. Total loss of the mitochondrial energy production is not compatible with life. Mitochondrial diseases are very variable in their features depending which cells and organ systems are involved. Symptoms range in severity from mild to fatal and may involve learning disabilities to organ failures.
The onset of mitochondrial disorders can occur in infants, but also in later adult life.