[Mitochondrial respiratory chain diseases. Evaluation and variability in 52 patients].
BACKGROUND
Clinical, electrophysiological, genetic and biochemical deficiencies variability were evaluated in 52 patients diagnosed of mitochondrial respiratory chain diseases (MRCD).


METHODS
26 men and 26 women, aged 19 to 79 years, were tested by clinical examination, electrophysiological techniques, muscle biopsy and genetic and biochemical studies.


RESULTS
The patients were classified into seven phenotypes: myopathy, chronic progressive external ophthalmoplegia, progressive ophthalmoplegia plus ataxia, Kearns-Sayre syndrome, mitochondrial encephalomyopathy with lactic acidosis and stroke episodes (MELAS), myoclonic encephalopathy with ragged-red fibers (MERRF), and encephalopathies. Each phenotype may begin by different ways. The electromiography showed myopathy in 39 cases and various types of neuropathy in 10. Ragged-red COX negative fibers or widespread electron microscopic abnormalities were found in 47 cases. Simple deletions, multiple deletions and three different point mutations were observed. Deficiency of complexes I, II, III and IV were found alone or in different associations.


CONCLUSIONS
MRCD shows wide variations in clinical, genetic and biochemical studies. Some patients with nonspecific manifestations, mainly of central nervous system, need careful attention and to be on account of diagnostic suspicion.
Arpa-Gutiérrez
F J
FJ
Servicio de Neurología, Hospital Universitario La Paz, Madrid, Spain. jarpag@ctv.es
Cruz-Martínez
A
A
Campos-González
Y
Y
Gutiérrez-Molina
M
M
Santiago-Pérez
S
S
Pérez-Conde
M C
MC
López-Pajares
M R
MR
Martín-Casarrubias
M A
MA
Rubio-Muñoz
J C
JC
del Hoyo
P
P
Arpa-Fernández
A
A
Arenas-Barbero
J
J
D000328:Adult; D000368:Aged; D001259:Ataxia / Q000235:genetics / Q000503:physiopathology; D001706:Biopsy; D004579:Electron Transport / Q000502:physiology*; D004594:Electrophysiology; D005260:Female; D006801:Humans; D007625:Kearns-Sayre Syndrome / Q000235:genetics / Q000503:physiopathology; D017241:MELAS Syndrome / Q000235:genetics / Q000503:physiopathology; D017243:MERRF Syndrome / Q000235:genetics / Q000503:physiopathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D028361:Mitochondrial Diseases / Q000235:genetics / Q000503:physiopathology*; D017237:Mitochondrial Encephalomyopathies / Q000235:genetics / Q000503:physiopathology*; D009154:Mutation; D017246:Ophthalmoplegia, Chronic Progressive External / Q000235:genetics / Q000503:physiopathology; D010641:Phenotype