Overview of MELAS
Patients with the syndrome of mitochondrial encephalomyopathy, lactic acidosis, and strokelike episodes (MELAS) have strokelike events that are acute in onset, often transient, and occasionally associated with a febrile illness. The vascular territories of focal brain lesions and the prior medical history of these patients differ substantially from those of typical patients with stroke.
This syndrome is due to point or microdeletion mutations in mitochondrial DNA; as in all diseases with mitochondrial transmission, the disease is inherited via the ovum and hence always from the mother. Mitochondrial DNA is 10 times more prone to mutation than somatic DNA. Since both normal mitochondria and abnormal mitochondria may be present in tissues, the clinical presentation can be heterogeneous. Cardiomyopathy due to mitochondrial disease may produce typical cardioembolic strokes in some patients.
MELAS is a complicated, multisystem disease. Since the symptoms, signs, and acute clinical presentations are so varied and the disease is relatively rare, the disease is misdiagnosed frequently. Although MELAS remains a largely untreatable condition, prevention and management of medical complications may prolong survival, adding to the benefit of establishing a diagnosis.
Although classic features are seen on muscle biopsy, a negative muscle biopsy does not rule out this disease. Without a clear pattern of signs and symptoms, the clinical suspicion may be insufficient to prompt genetic analysis.
A multidisciplinary team approach is needed in the diagnosis and further care of patients with MELAS. Genetic testing and counseling should be offered to family members.
For more information on stroke, see Hemorrhagic Stroke and Ischemic Stroke.
For patient education information, see the Stroke Center, as well as Stroke.