Pseudohypertrophic muscular dystrophy

Abstract

Observations are presented from an anatomical study provided by the body of a 16-year-old white male with pseudohypertrophic muscular dystrophy. These indicate that in this form of dystrophy all of the skeletal muscles are diseased. Degeneration proceeds in all, but at different rates. The function of a muscle, or portion of a muscle, is a fundamental factor in determining the rate at which it will deteriorate. Those muscles or portions of a muscle,performing the greatest degree of sustained activity wear out first and become replaced by fat. Those assuming the least degree of sustained activity suffer the least. Deformity in one part of the body as a result of muscle wasting facilitates the wasting of muscles in other portions of the body by causing them to become additionally activated in the performance of substitute or auxiliary roles. It appears that in this particular form of dystrophy the underlying molecular defect is intimately related to, or affected by, physical activity which hastens the muscle''s demise. This might also be true for the Leyden-Moebius form. The clinical distribution of muscle weakness alone makes it seem exceedingly unlikely that the same is true for myotonic dystrophy, Gower''s distal form, Erb''s juvenile form, the Landouzy-Dejerine form, or progressive external ophthalmoplegia.