Mitochondrial DNA and Professional Baseball

Patient description: twenty-six years old, a professional athlete making an annual salary of more than $2 million dollars. This is not the typical description of someone suspected of having a mitochondrial disorder but this may indeed be the case for Rocco Baldelli. Baldelli plays center field for the Tampa Bay Rays and has been on the disabled list since March of this year; reason given is "mitochondrial disorder."

Mitochondria are organelles or structures within our cells whose function is to produce energy. The mitochondria convert the energy from food into a form that the cells can use, called ATP. ATP is the energy source for muscles and to continue exercising or playing, muscles must continually produce ATP. The more strenuous the exercise, the greater are the demands on the muscle.

Mitochondria are unique cell structures in that they contain their own DNA. Changes or mutations in mitochondrial DNA can occur as inherited changes or may occur by chance. Disorders resulting from mitochondrial mutations often involve multiple organ systems but are most pronounced in organs and tissues with high energy demands. Examples of these organs and tissues include the heart, brain, and muscles. Mitochondrial DNA, if damaged, has little ability to repair itself. Therefore, these changes can accumulate over time and symptoms may take years to surface.

In the case of Rocco Baldelli, he noticed changes in his endurance and strength within the last two years. Basic baseball activities like running, batting, and throwing left him extremely fatigued and weakened after short workouts. These conditions can be frustrating because it is often very difficult to specifically identify an exact reason or cause and assign the symptoms a specific name. Baldelli will remain on the disabled list "indefinitely until we find out something else that could possibly improve my situation."

For more information on mitochondrial disorders you may visit the following websites: