Respiratory chain complexes defects: Complex IV . MELAS (cytochrome c oxydase) deficiency: Mitochondrial encephalomyopathy, lactic acidosis with stroke-like episodes syndrome (MELAS)..
Incidence
rare. Positive family history in 25%. Maternal inheritance. Mothers may also have short stature and deafness. No cases reported in Saudi Arabia.
Clinical Characteristics
Reccurrent episodes of stroke-like attacks with hemiparesis, hemianopsia, cortical blindness, often associated with headaches, seizures and vomiting. Episodes may be triggered by fever. Short stature, deafness, dementia, weakness, myopathy. 20% abnormal EEG. Muscle biopsy= ragged red fibres. Spongy degeneration of the brain. Lactic acidosis.
Precipitants
none
Provocation Tests
none
Diagnostic Procedures
(MELAS): DB-muscle