[Familial myopathy with exclusively cardiac clinical expression]

A case is presented of a familial form of apparently primary cardio-myopathy with findings on investigation and histology which were in favour of a generalised subclinical muscular disorder: a raised serum creatinine phosphokinase, persistent carnosinuria on a vegetarian diet, and under the light microscope several features indicative of a myogenic dystrophic condition on deltoid biopsy. From their clinical features, these original cases may be classified somewhere between primary familial heart disease and the cardiac complications of myopathies. The value of the creatinine phosphokinase isoenzymes and of muscle biopsy in situations such as these is discussed.