SURFEIT-1 gene analysis and two-dimensional blue native gel electrophoresis in cytochrome c oxidase deficiency.

ABSTRACT

Leigh syndrome, a progressive, often fatal, neurodegenerative disorder, is frequently associated with a deficiency in the activity of cytochrome c oxidase (COX), the last enzyme of the mitochondrial respiratory chain. In contrast to NADHubiquinone oxidoreductase and succinate dehydrogenase deficiencies, no mutations in nuclear genes encoding COX subunits have been identified thus far. Very recently, however, a Leigh syndrome complementation group has been identified which showed mutations in the SURFEIT-1 (SURF-1) gene. The results of a mutational detection study in 16 new randomly selected COX-deficient patients revealed a new mutation (C688T) in 2 patients and the earlier reported 845delCT mutation in 2 additional patients. In addition, we evaluated the diagnostic value of two-dimensional blue native gel electrophoresis. We show that this technique reveals distinct patterns of both fully and partially assembled COX complexes and is thereby capable of discrimination between COX-deficient SURF-1 and non-SURF-1-mutated patients.