Metabolic myopathies.
We consider recent developments in disorders affecting three areas of metabolism: glycogen, fatty acids, and the mitochondrial respiratory chain. Among the glycogenoses, new attention has been directed to defects of glycogen synthesis resulting in absence rather than excess of muscle glycogen ("aglycogenosis"). These include defects of glycogen synthetase and defects of glycogenin, the primer of glycogen synthesis. Considerable progress also has been made in our understanding of alterations of glycogen metabolism that result in polyglucosan storage. Among the disorders of lipid metabolism, mutations in the genes encoding two triglyceride lipases acting hand in hand cause severe generalized lipid storage myopathy, one associated with ichthyosis (Chanarin-Dorfman syndrome), the other dominated by juvenile-onset weakness. For the mitochondrial myopathies, we discuss the importance of homoplasmic mitochondrial DNA mutations and review the rapid progress made in our understanding of the coenzyme Q(10) deficiencies, which are often treatable.
DiMauro
Salvatore
S
Department of Neurology, College of Physicians and Surgeons, Columbia University Medical Center, Room 4-424B, 630 West 168th Street, New York, NY 10032, USA. sd12@columbia.edu
Garone
Caterina
C
Naini
Ali
A
D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism; D004247:DNA / Q000235:genetics / Q000378:metabolism; D004272:DNA, Mitochondrial / Q000235:genetics / Q000378:metabolism; D005227:Fatty Acids / Q000378:metabolism; D006003:Glycogen / Q000378:metabolism; D006801:Humans; D050356:Lipid Metabolism; D008661:Metabolism, Inborn Errors / Q000150:complications* / Q000235:genetics*; D028361:Mitochondrial Diseases / Q000150:complications; D017240:Mitochondrial Myopathies / Q000235:genetics; D009135:Muscular Diseases / Q000209:etiology*; D009154:Mutation
D004272:DNA, Mitochondrial; D005227:Fatty Acids; D006003:Glycogen; D004247:DNA