[Steinert disease associated with Klinefelter's syndrome].

Hypogonadism is common in Steinert disease but may also suggest other diagnoses. We report the case of a patient with Steinert's disease who also had Klinefelter syndrome disclosed at 62 years of age by an osteoporotic fracture. Both clinical diagnoses were confirmed by karyotype and genetic analysis. The hypogonadism assigned to the Klinefelter syndrome for this patient may have influenced the clinical expression of the muscular pathology.