Benign X-linked (Emery-Dreifuss) muscular dystrophy is not benign.

Emery-Dreifuss muscular dystrophy is sometimes referred to as benign X-linked muscular dystrophy. We present two young patients with this disorder who had severe cardiovascular complications including: conduction disease, major thromboembolic events, valvular dysfunction with congestive cardiac failure, ventricular tachyarrhythmias, and sudden cardiac death. Of these cardiac problems, only conduction disease has been previously emphasized. This form of muscular dystrophy is not benign--it has malignant cardiac manifestations.