<unk>  is a disorder of the reproductive system which results in lack of function of the gonads (ovaries or testes).<unk>  is caused by several conditions which may be congenital, acquired, genetic, or malignancies.<unk>  may be classified on the basis of etiology and the site causing the defect into primary or secondary<unk> . Primary<unk>  results from defect in the gonads themselves and it is characterized by high level of the gonadotropin hormones (FSH and LH). Secondary<unk>  indicates a defect in pituitary gland or hypothalamus and presents with a low level of gonadotropin releasing hormone, FSH, and LH. Genetic mutations that can cause<unk>  include ANOS 1, SOX10, SEMA3A, IL17RD and FEZF1. Other genes include KISS, GNRNH, and PROK.<unk>  must be differentiated from diseases that may cause delayed puberty or infertility, such as Klinefelter syndrome, Kallmann syndrome and cryptorchidism. The prevalence of<unk>  is estimated to be 38,700 per 100,000 individual aging 45 years. The incidence of<unk>  is 1230 per 100,000 persons.<unk>  affects men more than women and its prevalence increases with age.<unk>  has many risk factors like dyslipidemia, obesity, malignancies and alcohol intake. If<unk>  left untreated, patients will end up with infertility and rheumatic autoimmune diseases.<unk>  can cause complications like gynecomastia and delay of puberty in the prepubertal patients. It can also cause depression and cardiovascular stroke in the adults.<unk>  usually has a good prognosis with the proper treatment. Patients with<unk>  usually present with loss of the secondary sexual characteristics. Male patients present with infertility, loss of libido and erectile dysfunction. Female patients present with amenorrhea and loss of pubic hair. Laboratory evaluation may reveal low testosterone levels and variable FSH and LH levels according to the cause of<unk>  whether primary or secondary. The mainstay of treatment for<unk>  is testosterone replacement therapy and it can be administrated through different regimens injected, transdermal or buccal. In females, estrogen replacement is helpful besides testosterone.
Hypogonadism
Clitoromegaly
Delayed puberty
Precocious puberty
Adrenal atrophy
Pubertal delay
Hyperandrogenism
Penis enlargement