Mitochondrial myopathy with autosomal dominant inheritance--report of a family and review of the literature
Kawai, H.; Akaike, M.; Yokoi, K.; Tamaki, Y.; Saito, S.
Rinsho Shinkeigaku 33(2): 162-168
1993
ISSN/ISBN: 0009-918X PMID: 8319387 Document Number: 415897
We report a family of mitochondrial myopathy which appeared to be interited as an autosomal dominant trait. The proband is a 58-year-old Japanese male, who presented with bilateral ptosis, chronic progressive ophthalmopletia, dysphagia, and atrophy of proximal muscles in the upper extremities. There was no cataract or retinal degeneration. Serum creatine kinase (CK) and lactic acid levels were normal. Cardiac evaluations were normal. Muscle biopsy revealed 7% of ragged red fibers. Cytochrome c oxidase activity in the muscle was decreased to 50% of the control value. PCR analysis of muscle mitochondrial DNA revealed 3 large-scale deletions in the non-D-loop regions, ranging in size from 4.2 kb to 5.2 kb. His father, three siblings, and the two children had symptoms similar to the proband. We have reviewed forty-five individuals from six families, including our family, who had mitochondrial myopathy with autosomal dominant inheritance. Frequent manifestations include chronic progressive ophtalmoplegia (91.2%), ptosis (95.6%), hearing loss (72.7%), dysphagia (60.0%), limb weakness (74.1%), and respiratory muscle weakness (75.0%). Interestingly, there is no individual with retinal degeneration or cardiac involvement. Serum CK and lactic acid levels may be elevated. CT of the head is normal. Muscle biopsy shows ragged red fibers and the frequency of cytochrome c oxidase-negative fibers ranges from 0 to 38%. Multiple large-scale deletions of mitochondrial DNA, ranging in size from 4.2 to 8.3 kb, are found in the muscle, all of which are located in the non-D-loop region of the mitochondrial DNA. The multiplicity of deletions may be one to the characteristic features of this form of mitochondrial myopathy.