Constitutional delay (53%)
Functional hypogonadotropic hypogonadism (19%)
O Chronic illness, malnutrition, overtraining, hypothyroidism, growth hormone deficiency
Hypogonadotropic hypogonadism (HH) (12%)
o Intracranial disorders including tumors and congenital abnormalities
o Isolated gene defects such as DAX1, Kallman Syndrome, GnRH/receptor
o Hypopituitarism
o Part of a syndrome: Prader-Willi, Bardet-Biedl, Laurence-Moon
o Permanent damage to hypothalamus/pituitary due to secondary disease i.e. iron overload
Hypergonadotropic hypogonadism (13%)
o Abnormal sex chromosomes: Turner syndrome, Klinefelter Syndrome
o Damage to gonads: trauma, torsion, chemotherapy, radiation, galactosemia, iron overload, cystic fibrosis, mumps orchitis, anorchia, cryptorchidism
o Disorders of sex differentiation: androgen insensitivity, gonadal dysgenesis
Unclassified (3%).
