OXPHOS and mtDNA alterations in a family with spastic paraparesis

Objective - To study muscle biopsies in hereditary spastic paraparesis (HSP). Methods - We analyzed oxidative phosphorylation activities and mtDNA in 3 individuals from an HSP family. Results - We found histochemical evidence for mitochondrial proliferation and cytochrome c oxidase negative fibers. Biochemically, there was an important reduction of the activities of complexes I and IV in 3 patients. In addition, multiple mtDNA deletions (ranging 4.0-7.0 kb) were found in 2 cases by PCR but not by Southern blot. Conclusion - We suggest the use of a muscle biopsy when examining HSP patients. HSP can represent a disorder of nuclear mitochondrial intercommunication.