Symptoms of MELAS vary depending on what area of the body is affected. Symptoms related to the brain, nervous system and muscles may include:
- Difficulty understanding or thinking
- Temporary muscle weakness or paralysis (hemiparesis)
- Difficulty speaking
- Changes in behavior
Symptoms related to the buildup of lactic acid in the body may include:
- Abdominal pain
- Muscle weakness
- Difficulty breathing
The condition is also associated with stroke-like episodes. Symptoms include:
- Loss of (or abnormal) sensation in an arm, leg or one side of the body
- Weakness or paralysis of an arm or leg or one side of the body
- Partial loss of vision or hearing
- Double vision
- Slurred speech
- Problems thinking of or saying the right word
- Inability to recognize parts of the body
- Imbalance and falling
Causes and Risk Factors
MELAS is caused by a change in one of several genes that help build mitochondria, cell structures that convert food into energy.
MELAS is usually diagnosed in childhood, between the ages of 2 and 15. Patients diagnosed between 15 and 40 years of age are considered to have delayed onset of the condition. Nearly 75 percent of cases are diagnosed before the age of 20.
Patients who have MELAS in their family, particularly those with a mother who has MELAS, are at an increased risk of developing the condition.
MELAS affects men and women at equal rates.