The disorder is inherited as an X-linked recessive or autosomal dominant trait with variable expressivity. Serum FSH and LH levels are low or low-normal, and plasma testosterone levels are low for the age. The levels of other pituitary hormones are normal. The defect appears to be in the synthesis or release of GnRH and has a severity varying from the complete absence of pulsatile LH secretion, to impairment in amplitude and frequency of LH secretion.
Distinction between this disorder and delayed puberty is difficult in boys of early or midpubertal age; the presence of microphallus, anosmia, or a positive family history may help in diagnosis. Sometimes, differentiation of the two states may require long observation.
