What is the cause of hypogonadism in Klinefelter syndrome?

In Klinefelter syndrome, hypogonadism occurs primarily due to a failure of the gonads, specifically the testes, to function properly. This condition is often characterized by the presence of an extra X chromosome in males (most commonly 47, XXY instead of the typical 46, XY), which interferes with normal testicular development and hormone production. As a result, men with Klinefelter syndrome typically have lower levels of testosterone, leading to the symptoms of hypogonadism such as infertility, reduced muscle mass, and other hormonal imbalances.

The other options describe conditions that do not directly cause hypogonadism in this syndrome. Excess production of testosterone does not align with the condition, as Klinefelter syndrome is associated with lower testosterone levels. An abnormality in the Y chromosome contributes to the chromosomal profile but is not the direct cause of the gonadal failure linked to hypogonadism. Lastly, overproduction of FSH (Follicle-Stimulating Hormone) and LH (Luteinizing Hormone) can be a consequence of the hypogonadism due to feedback mechanisms, but they are not the underlying cause of the gonadal dysfunction seen in Klinefelter syndrome.