Genetics and physiology of the myotonic muscle disorders
Article Abstract:
Myotonic muscle disorders are characterized by delayed muscle relaxation following contraction or mechanical stimulation. Myotonic disorders are classified as either dystrophic or non-dystrophic. Myotonic dystrophy differs from the non-dystrophic forms in that there is muscle wasting and it affects more than one system in the body. Physiologically, myotonia is a disorder of muscle-membrane excitability, apparently caused by abnormal regulation of the sodium channels. The myotonic disorders are inherited. Through DNA analysis of affected families and studies of defective proteins, three distinct genes have been identified as causes of myotonia. Genetic screening for certain myotonias - hyperkalemic periodic paralysis, paramyotonia congenita and myotonic dystrophy - is now possible. Because myotonic disorders are rare, knowledge about the effectiveness of drug therapy in treating these disorders is limited.
Publication Name: The New England Journal of Medicine
Subject: Health
ISSN: 0028-4793
Year: 1993
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Mitochondrial respiratory-chain diseases
Article Abstract:
The genetics of mitochondrial diseases is reviewed. Topics include mitochondrial genetics, metabolic pathways in mitochondria, mitochondrial DNA and the mitochondrial respiratory chain, respiratory chain disorders caused by defects in mitochondrial DNA, mutations of mitochondrial DNA that cause disease, respiratory chain disorders caused by defects in nuclear DNA, and therapeutic approaches. Mitochondria are structures inside cells that create energy from food.
Publication Name: The New England Journal of Medicine
Subject: Health
ISSN: 0028-4793
Year: 2003
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