Type 1 Diabetes Mellitus and Klinefelter Syndrome.

A 60-year-old male patient with type 1 diabetes mellitus (T1DM) was admitted for glycemic control. The patient exhibited abdominal adiposity, osteoporosis, and high insulin requirement (>100 U), and we suspected hypogonadism. A physical examination revealed small testes and thin pubic hair, laboratory examination found high luteinizing hormone (LH) and follicle stimulating hormone (FSH) levels and low testosterone levels, and a chromosome analysis (47, XXY) indicated hypogonadism due to Klinefelter syndrome (KS). KS is associated with autoimmune diseases and patients positive for diabetes related auto-antibodies. In male patients with T1DM and abdominal adiposity, the concurrence of KS should be taken into consideration.