# A case of osteoporotic fracture leading to diagnosis of Klinefelter syndrome in a 76-year-old man

## TL;DR

An elderly man's osteoporotic fracture led to the diagnosis of Klinefelter syndrome, highlighting the importance of considering hypogonadism in men with unexplained bone loss.

## Contribution

This case emphasizes the underdiagnosis of Klinefelter syndrome in older men and the value of considering hypogonadism in cases of unexplained bone loss.

## Key findings

- A 76-year-old man with a rib fracture was found to have Klinefelter syndrome (47,XXY) and hypogonadism.
- Bone mineral density testing confirmed clinical osteoporosis despite no prior suspicion of KS.
- The case underscores the need for hormonal evaluation in men with unexplained bone loss.

## Abstract

Klinefelter syndrome (KS) is the most prevalent sex chromosome disorder in men but often remains clinically silent until later life. We describe an elderly man whose evaluation for a rib fracture uncovered the diagnosis. A 76-year-old male presented after a low-impact fracture during a coughing episode. Clinical history revealed delayed sexual maturation, small testes, infertility, and mild gynecomastia. Hormonal testing demonstrated markedly reduced testosterone with elevated luteinizing and follicle-stimulating hormones, suggesting primary testicular failure. Karyotype analysis confirmed 47,XXY. Bone mineral density testing revealed osteopenia, meeting criteria for clinical osteoporosis. He received intravenous zoledronic acid, while androgen therapy was postponed pending urologic assessment. This case emphasizes that KS can remain undetected for decades and highlights the need to consider hypogonadism in men with unexplained bone loss. Early recognition facilitates appropriate treatment and long-term monitoring for associated systemic complications.