Fulminant Respiratory Muscle Paralysis, an Expanding
Clinical Spectrum of Mitochondrial
A3243G tRNALeu Mutation
Jakkrit Amornvit MD*,
Nath Pasutharnchat MD*, Monvasi Pachinburavan MD**,
Sungkom Jongpiputvanich MD***, Yutthana Joyjinda MSc****
Affiliation :
* Division of Neurology, Department of Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
** Division of Pulmonary and Critical Care Medicine, Department of Medicine, Faculty of Medicine,
Chulalongkorn University, Bangkok, Thailand
*** Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
**** Neuroscience Centre for Research and Development, & WHO Collaborating Centre for Research Training
on Viral Zoonoses, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
Mitochondrial disease is a group of rare disorders, caused by mitochondrial dysfunction. They are usually the
result of mutations of either mitochondrial DNA or nuclear DNA. A3243G transition in the tRNALeu is one the most frequent
mutations of the mitochondrial DNA. Phenotypic expression of this mutation varies. The most well-recognized phenotype
is Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome. Isolated myopathy with
respiratory muscle weakness in this mutation has been rarely documented. The authors reported a 20-year-old Asian female
presenting with a fulminant hypoventilatory respiratory failure with mild weakness of the limbs. Electrophysiologic study
showed evidences of myopathy. Restrictive physiology of the lungs was demonstrated by pulmonary function test.
Subsarcolemmal accumulation of mitochondria was demonstrated by Gomori trichrome and succinate dehydrogenase stains.
Genetic study revealed the A3243G mutation in mitochondrial DNA in peripheral blood. Isolated mitochondrial myopathy
severely affecting respiratory muscles may be considered as an uncommon clinical spectrum of A3243G mitochondrial
disease.
Keywords : Mitochondrial disease, A3243G mutation, Neuromuscular respiratory failure, Bilateral diaphragmatic weakness,
Myopathy
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