Lactate dehydrogenase A subunit (LDH-A) deficiency is an inherited metabolic myopathy of glycolysis. The severity of this disease varies from case to case. We reported non-consanguineous male sibling cases who had severe muscle pain and rhabdomyolysis during anaerobic exercise. Genetic analysis revealed 20 base pair deletion of the sixth exon of the LDH-A gene. There was no difference in the gene abnormality between our patients and previously reported female cases who had history of consanguinity and lower degree of symptoms. The differences in disease severity were not due to genomic abnormality in our two families.
(Internal Medicine 34: 326-329, 1995)