A study of a family with inherited disease of cardiac and skeletal muscle. Part I. Clinical, electrocardiographic, echocardiographic, haemodynamic, electrophysiological and electron microscopic studies

A family consisting of parents and their 6 sons were investigated to elucidate the relationship between a hypertrophic cardiomyopathy, musculoskeletal abnormalities and mental subnormality. The proband was diagnosed as having definite hypertrophic obstructive cardiomyopathy and the remaining family members were shown to have a spectrum of hypertropic non-obstructive cardiomyopathy. Mild muscle weakness was present in 3 sons. All the subjects except for 1 son showed definite signs of electromyographic abnormality, whereas sensory and motor conduction velocities were normal. All the EEGs except for that of the proband were normal. Testicular hypoplasia was present in 3 sons. The inheritance pattern appears to be polygenic autosomal recessive in type. Definite evidence of linkage between hypertrophic cardiomyopathy and HLA awaits further data.