DYSTROPHIN POSITIVE FIBERS IN DUCHENNE DYSTROPHY - ORIGIN AND CORRELATION TO CLINICAL COURSE

In 132 DMD muscle biopsies we investigated the presence of dystrophin- positive fibers and the relationship of dystrophin immunohistochemical pattern to the clinical severity of the disease. Reverted fibers were detected in 37% of patients; their prevalence increased significantly in each biopsy with age of patients. We suggest that reversion occurs in satellite cells, when muscle differentiation is completed. The lon gitudinal extent of dystrophin-positive domain spans a maximum length of 900 mu m. No correlation was found between the presence of reverted fibers and the clinical severity of DMD, whereas a milder form of Duc henne dystrophy was observed in patients showing a faint reaction in a ll fibers. The occurrence of reverted fibers is independent of the typ e of gene mutation; however, a higher proportion of cases with reverte d fibers was found among patients with gene duplications. (C) 1995 Joh n Wiley & Sons, Inc.