myopathy with lactic acidosis—hereditary
Definition An autosomal recessive metabolic disease (OMIM:255125) characterised by lifelong severe exercise intolerance, in which minor exertion causes fatigue of active muscles, shortness of breath, palpitations and lactic acidosis.
Pathogenesis Lack of mitochondrial iron-sulphur proteins and impaired muscle oxidative metabolism.
Molecular pathology Defects of ISCU, which encodes an enzyme involved in the assembly or repair of the iron-sulphur clusters in iron-sulphur proteins, cause myopathy with lactic acidosis—hereditary.
Synonyms Myogloblinuria due to abnormal glycolysis, myopathy with deficiency of succinate dehydrogenase and aconitase, myopathy with exercise intolerance—Swedish type