PROGRESSION OF MYOPATHOLOGY IN KEARNS-SAYRE SYNDROME - A MORPHOLOGICAL FOLLOW-UP-STUDY

We report on the progression of myopathology by comparing two biopsies from a patient with a Kearns-Sayre-Syndrome. The first biopsy was taken in 1979 and showed 10 % ragged-red fibers. Myopathic changes were slight including internal nuclei and fiber splitting in 10 % of the fibers. Electron microscopy revealed typical mitochondrial abnormalities with regard to number and shape. In 1989 a second biopsy was performed for an extended analysis of mitochondrial DNA. This time less than 5 % of all fibers were ragged-red. Severe myopathic changes could be detected which so far has rarely been reported in mitochondrial cytopathy.