[A patient with Kennedy-Alter-Sung syndrome showing cardiomyopathy].

A 31-year-old man with a history of progressive muscular atrophy and weakness from around 22 years of age, recently experienced arrhythmia. On examination he showed gynecomastia and slight proximal weakness in both upper and lower extremities. Androgen receptor gene analysis showed an increased number of tandem CAG repeats in exon 1, thus leading to a diagnosis of Kennedy-Alter-Sung (KAS) syndrome. Cardiological investigations including echocardiography, scintigraphy and catheterization disclosed dilated cardiomyopathy. Cardiac muscle biopsy showed myocardial cell degeneration. KAS syndrome is causatively related to androgen receptor gene abnormality. This receptor is widely distributed throughout human body, including the genital tract, spinal cord, liver, and heart. Androgen receptor dysfunction may induce cardiac muscle involvement in patients with KAS syndrome, producing the previously unknown pathophysiology of cardiomyopathy.