6.8.2 Mitochondrial Encephalopathy, Lactic Acidosis and Stroke-like episodes (MELAS)

Description:
A genetically heterogeneous mitochondrial disorder with a variable clinical phenotype, including features of central nervous system involvement (seizures, hemiparesis, hemianopia, cortical blindness, sensorineural deafness and/or episodic vomiting) and, frequently, headache, which is either recurrent in migraine-like attacks or a presenting symptom of stroke-like episodes.

Diagnostic criteria:
A. Recurrent attacks of headache fulfilling criterion C
B. A mitochondrial genetic abnormality associated with MELAS has been demonstrated
C. Either or both of the following:

    1. recurrent migraine attacks with or without aura
    2. acute headache preceding focal neurological deficits and/or seizures

D. Not better accounted for by another ICHD-3 diagnosis.

Comment:
MELAS syndrome, comprising mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes, is a genetically heterogeneous mitochondrial disorder with a variable clinical phenotype. The disorder is accompanied by features of central nervous system involvement, including seizures, hemiparesis, hemianopia, cortical blindness, sensorineural deafness and episodic vomiting. Headache is frequent in MELAS, either as recurrent migraine-like attacks or as the presenting symptom of stroke-like episodes. The high frequency of migraine-like attacks as part of MELAS has led to the hypothesis that mitochondrial mutations may play a role in migraine with aura, but the 3243 mutation was not detected in two groups of subjects with 1.2 Migraine with aura. Other yet-undetected mutations may play a role in both migraine and ischaemic stroke, since migraine attacks, mostly with aura, also occur in other mitochondrial disorders.