Abstract
To the Editor: The family with Becker's cardiomyopathy described by Muntoni et al. (Sept. 23 issue)1 and the two families described previously by Towbin et al.2 strongly support the argument that 5' mutations in the dystrophin gene may cause a selective cardiomyopathy. My colleagues and I have studied a fourth family also affected by severe cardiomyopathy and mild Becker's muscular dystrophy with a 5' gene mutation that differs from that described in other reports (unpublished data). The hypothesis that a selective deletion of the muscle promoter causes cardiomyopathy without skeletal myopathy is not supported by other published reports of subjects. © 1994, Massachusetts Medical Society. All rights reserved.