In terms of numbers, Klinefelter's syndrome is the most frequent disorder of the sex chromosomes (1:500 to 1:1'000 of all men). The affected men have a spare X chromosome.

The following symptoms indicate such a clinical diagnosis:

• Unproportionate growth in height
• Gynecomastia, hypogonadism
• Small, hard testicles (testicular atrophy)
• Sparse body hair
• Infertility
• Frequent diabetes mellitus

Today the definitive diagnosis is made based on a karyogram.
The therapy consists in the substitution of testosterone.

Macroscopic image