Progressive dilated cardiomyopathy in a patient with previously unrecognized Klinefelter syndrome: a case report

Klinefelter syndrome (KS), the most common sex chromosome disorder in males, is characterized by small testes, gynecomastia, and infertility. As environmental factors and population health trends change, there is an increasing trend in cardiac problems and related deaths among these patients. Yet definitive evidence linking this syndrome to cardiac abnormalities remains scarce. This case study discusses a 40-year-old man with KS and dilated cardiomyopathy who was evaluated for heart transplantation. The patient presented to the cardiology department with recurrent chest tightness, shortness of breath, dry cough, and facial oedema over several years. Approximately five years earlier, the patient was diagnosed with dilated cardiomyopathy. Following symptomatic treatment with cardiac glycosides, diuretics, and rate control, the left ventricular ejection fraction (LVEF) improved only slightly (from 25% to 30%). During a second hospitalization, genetic testing identified an X-chromosome duplication consistent with Klinefelter syndrome. Testosterone was at the lower end of the normal range. The patient was evaluated for heart transplantation but declined due to financial constraints. When dilated cardiomyopathy has no obvious cause, genetic investigation should follow. Karyotyping or comprehensive genetic testing may identify an underlying condition with systemic implications; KS is one such example. In this patient, an acute cerebral infarction of undetermined cause occurred between the two admissions. Men with a 47,XXY karyotype are at increased risk of death from cerebrovascular disease, and earlier detection of KS in this patient would have allowed closer monitoring of this risk.