Mitochondrial Disorders

Patient/Family Story

A.M. was well until 6 years of age. She was always a little on the short side and was more sedentary than her older siblings. She walked a little late and did not run as fast as other children her age. We knew there was a significant problem when she started having a lot of difficulty going up stairs. She was seen by a doctor who did some blood tests. A lactate level was elevated. She then began having episodes where she would have transient loss of control or sensation on either side of the body. An MRI of the brain showed small strokes. Genetic testing showed that she had the mutation for MELAS.

What is a Mitochondrial Disorder?

Mitochondria are the energy factories of the cell. Abnormalities in mitochondrial DNA or genes produce metabolic disorders that affect different parts of the body, including muscle and brain. Mitochondrial disorders can be inherited or sporadic. When inherited, the abnormal genes always come from the mother, since all mitochondria are of maternal origin. Two mitochondrial disorders can be associated with epileptic seizures. One is MELAS: mitochondrial encephalopathy, lactic acidosis (meaning too much lactic acid in the blood), and stroke-like episodes. MELAS can lead to stroke-like episodes at a young age (usually before 40), seizures, dementia, headaches, vomiting, unsteadiness, and ill effects from exercise. Persons with MELAS can have both generalized (including myoclonic and tonic-clonic) and partial seizures.

The other mitochondrial disorder with epileptic seizures is MERRF: myoclonic epilepsy with ragged red muscle fibers). MERRF is one of the progressive myoclonic epilepsies. It can also be associated with hearing loss, unsteadiness, dementia, and ill effects from exercise. In addition to myoclonic seizures, patients with MERRF often have generalized tonic-clonic seizures

There are other mitochondrial disorders that do not fit clearly into the MELAS or MERRF syndromes but which can cause epilepsy and additional neurological problems.

How are mitochondrial disorders treated?

There is no specific cure yet for mitochondrial disorders. Treatment is geared towards controlling symptoms and slowing the progression of the disease. A doctor may prescribe a combination of supplements such as Co-enzyme Q 10 or L-Carnitine in addition to other supplements. For patients who have isolated deafness, evaluation for a cochlear implant may be possible. For patients with seizures, standard antiepileptic medications are used.