The mitochondrial myopathies are a genetically, biochemically, and clinically heterogenous group of disorders which have been difficult to classify and study. They are currently classified on the basis of a clinical constellation of symptoms and histochemical properties of skeletal muscle biopsies. Their molecular basis remains obscure, but there is recent evidence for deletions in the mitochondrial DNA of some of these patients. We propose to apply the powerful techniques of molecular biology to these disorders and to test the hypothesis that mutations mitochondrial DNA play a major pathogenetic role. The long term objective of this project is the characterization of the molecular genetic basis of the mitochondrial myopathies, beginning with a detailed analysis of a well-characterized patient.
The specific aims of this proposal are: (1) the preparation of a set of molecular DNA clones that span the entire human mitochondria genome; (2) the production of a complete set of molecular mitochondrial DNA clones from the proband patient with mitochondrial encephalomyopathy, lactic acidosis, and stroke (MELAS) syndromes; (3) the nucleotide sequence determination of the three mitochrondrially-encoded cytochrome oxidase genes and comparison to the published normal sequence; (4) the screening of a population of mitochondrial myopathy patients for large mitochondrial DNA deletions by Southern hybridization probe analysis, molecular cloning, and polymerase chain reaction (PCR) amplificance of any observed mutations in highly conserved regions by assessing mitochondrial protein synthesis, by focused DNA analysis of first degree relatives of affected patients, and by in situ hybridization studies of skeletal muscle. These studies should further our understanding of the molecular genetic basis of the mitochondrial myopathies. Such information is a necessary prerequisite of the proper diagnosis, genetic counselling, and eventual treatment of these patients.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Clinical Investigator Award (CIA) (K08)
Project #
5K08NS001359-02
Application #
3084332
Study Section
Neurological Disorders Program Project Review B Committee (NSPB)
Project Start
1989-07-01
Project End
1994-06-30
Budget Start
1990-07-01
Budget End
1991-06-30
Support Year
2
Fiscal Year
1990
Total Cost
Indirect Cost
Name
Johns Hopkins University
Department
Type
Schools of Medicine
DUNS #
045911138
City
Baltimore
State
MD
Country
United States
Zip Code
21218
Johns, D R; Sadun, A A (1994) Cuban epidemic optic neuropathy. Mitochondrial DNA analysis. J Neuroophthalmol 14:130-4
Johns, D R; Neufeld, M J; Hedges 3rd, T R (1994) Mitochondrial DNA mutations in Cuban optic and peripheral neuropathy. J Neuroophthalmol 14:135-40
Johns, D R; Heher, K L; Miller, N R et al. (1993) Leber's hereditary optic neuropathy. Clinical manifestations of the 14484 mutation. Arch Ophthalmol 111:495-8
Johns, D R; Smith, K H; Miller, N R et al. (1993) Identical twins who are discordant for Leber's hereditary optic neuropathy. Arch Ophthalmol 111:1491-4
Johns, D R; Smith, K H; Savino, P J et al. (1993) Leber's hereditary optic neuropathy. Clinical manifestations of the 15257 mutation. Ophthalmology 100:981-6
Johns, D R; Stein, A G; Wityk, R (1993) MELAS syndrome masquerading as herpes simplex encephalitis. Neurology 43:2471-3
Johns, D R; Neufeld, M J (1993) Cytochrome c oxidase mutations in Leber hereditary optic neuropathy. Biochem Biophys Res Commun 196:810-5
Johns, D R; Neufeld, M J (1993) Pitfalls in the molecular genetic diagnosis of Leber hereditary optic neuropathy (LHON). Am J Hum Genet 53:916-20
Flanigan, K M; Johns, D R (1993) Association of the 11778 mitochondrial DNA mutation and demyelinating disease. Neurology 43:2720-2
Heher, K L; Johns, D R (1993) A maculopathy associated with the 15257 mitochondrial DNA mutation. Arch Ophthalmol 111:1495-9

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