[Molecular studies in Cuban patients with progressive external ophthalmoplegia].
BACKGROUND
The mitochondria, subcellular organelles which possess their own DNA (mtDNA), produce most of the energy, in the form of ATP, which is necessary for life. This mtDNA may have diverse molecular defects which have been associated with a great variety of clinical syndromes. Deletions in mtDNA are one of the common mutations in patients with mitochondrial myopathies, which in the great majority present with the common symptom of progressive external ophthalmoplegia. In this study we report our findings in eight Cuban families with suspected mitochondrial disease.


OBJECTIVE
To characterize these patients from the molecular point of view, which would allow a preliminary understanding of the behavior of these deletions in Cuban patients.


METHODS
We studied nine patients from eight Cuban families in whom mitochondrial encephalomyopathy was suspected. We analyzed the presence of ragged red fibres, the enzymatic activity of the mitochondrial respiratory chain and detection of mtDNA mutations. We used the technique of restriction length polymorphism analysis for detection of deletions.


RESULTS
Histochemical studies showed the presence of COX negative ragged red fibres in seven of the patients studied. The enzymatic activity of the mitochondrial respiratory chain was normal in all the patients. We detected four patients with single deletions of mtDNA, and one with multiple deletions and of the patients had the A3243G mutation.


CONCLUSIONS
With the methods used we were able to determine the presence of a mitochondrial disorder in seven of the eight families studied and deletions of mtDNA were detected as the cause of the illness in five. The disorder was always associated with progressive external ophthalmoplegia and COX negative ragged red fibres.
Rodríguez-Hernández
M
M
Instituto de Neurología y Neurocirugía, Ciudad de La Habana, Cuba. mrguezh@infomed.sld.cu
Hirano
M
M
Arrieta
T
T
Lestayo
Z
Z
Estrada
R
R
Santiesteban
R
R
Guerra-Badía
R
R
Galarraga
J
J
Gutierres
J
J
Hechevarría
E
E
Andreu
A
A
Montoya
J
J
DiMauro
S
S
D000293:Adolescent; D000328:Adult; D015139:Blotting, Southern; D003462:Cuba / Q000453:epidemiology; D004252:DNA Mutational Analysis; D004272:DNA, Mitochondrial / Q000235:genetics*; D004579:Electron Transport / Q000235:genetics; D003576:Electron Transport Complex IV / Q000378:metabolism; D005260:Female; D017353:Gene Deletion; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D017246:Ophthalmoplegia, Chronic Progressive External / Q000201:enzymology / Q000453:epidemiology* / Q000235:genetics*; D017354:Point Mutation / Q000235:genetics; D012150:Polymorphism, Restriction Fragment Length
D004272:DNA, Mitochondrial; D003576:Electron Transport Complex IV