DYSTROPHIN EXPRESSION IN THE DEVELOPING CONDUCTION SYSTEM OF THE HUMAN HEART

Duchenne muscular dystrophy (DMD) is frequently associated with myocar dial involvement. Dystrophin, the DMD protein, is found at the plasmam embrane of striated muscle fibers. Although dystrophin is missing in m ost or all muscle fibers of DMD patients, cardiac muscle is not as sev erely affected as skeletal muscle. Therefore it is of great importance to study the expression of dystrophin in normal cardiac muscle. We pe rformed immunohistochemical studies and examined cardiac muscle of fet uses of 8 to 13 weeks of development on dystrophin expression. At thes e stages dystrophin is observed in the myocytes of the developing vent ricular conduction system and in the atrial cardiomyocytes. Dystrophin was absent from the heart of a 12-week-old DMD fetus. (C) 1995 Wiley- Liss, Inc.