Testosterone treatment in male patients with klinefelter’s syndrome

Abstract

Klinefelter’s syndrome (KS) represents the most common sex chromosomal anomaly observed in men. Hypogonadism is a quite common complication of KS, with more than 75% of KS affected during their life. The aim of the present chapter is to systematically summarize and review all available evidence related to testosterone (T) treatment (testosterone replacement therapy [TRT]) in KS subjects emphasizing and discussing uncertain areas. In the vast majority of cases, hypogonadism in KS occurs in adulthood although some evidence suggests that T deficiency is already present during the gestational period. For the latter reasons, an early T trial, within the first 3–6 months of life, has been suggested, in order to improve brain development and contributing to better cognitive functioning and social behaviors. However, present data do not support this approach. TRT modalities in the event of a delayed puberty or in adulthood do not differ from those used in the general population. Some data have suggested that hypogonadism can play a direct role in some of the KS complications such as reduced bone mineral density, obesity, metabolic disturbances, and increased cardiovascular risk. However, similar to what has been observed in the general population, available evidence indicates that TRT in KS has an effect mainly on restoring sexual function whereas data on body composition, metabolic profile, bone density, and mood are more conflicting.