[Myotonic dystrophy (urological features and histochemical findings in muscle) (author's transl)]

Dilatation of the renal pelvis, ureters and bladder appeared in two brothers with myotonic dystrophy (aged 26 and 29 years), probably as a result of involvement of the smooth muscles of these organs. Histochemical differentiation of skeletal muscle fibres (main fibre types I and II, after Engel) indicated a predominant size reduction in type I fibres on demonstrating myofibrillary ATPase. In addition, demonstration of this enzyme also revealed a marked shift of the fibre type proportions in favour of type I. Isolated reduction in gammaG-globulins was also demonstrated. A defect of cellular and humoral response was excluded.