Some cases of KS/HH appear to reverse during adult life where the HPG axis resumes its normal function and GnRH, LH, and FSH levels return to normal levels. This occurs in an estimated 10 to 22% of people, primarily normosmic CHH cases rather than KS cases and only found in people who have undergone some form of testosterone replacement therapy. It is only normally discovered when testicular volume increases while on testosterone treatment alone and testosterone levels return to normal when treatment is stopped. This type of KS/HH rarely occurs in cases where males have had a history of un-descended testes.