Testosterone is the hormone responsible for masculine growth and development in male, when this hormone is not produced enough the condition is known as Male hypogonadism. This condition may is from the birth of an individual or it may occur in the middle due to injuries or infections.
The minimal incidence estimate of Male hypogonadism in Finland was 1:48 000, with clear difference between males (1:30 000) (p = 0.02). 7 known KS genes (KAL1, FGFR1, FGF8, PROK2, PROKR2, CHD7, and WDR11) in these 30 well-phenotyped probands revealed mutations in KAL1 (3 men) and FGFR1 (all 5 women vs. 4/25 men)
Treatments for this condition might be based on the severity and age of occurrence, in few cases testosterone replacement might be a cure.