Nevertheless, a brief outline of the workup of patients with this disorder is appropriate. Patients grow normally until puberty but may reach eunuchoid proportions because of delayed closure of epiphyses. Physical examination shows absence of breast development, immature female external genitalia, minimal pubic hair, an atrophic vagina, and a small uterus.
Gonadotropin levels are low, reflecting the central origin of the defect.
Permanent absence of GnRH can be very difficult to distinguish from constitutional delay of puberty, a delayed appearance of the pubertal increase in GnRH secretion. The presence of anosmia identifies the permanent GnRH deficiency of Kallmann's syndrome. Conversely, a history of late puberty in the mother points to constitutional delay. Menarche is delayed in some girls who exercise vigorously or diet stringently. Ballet dancers, long-distance runners, and girls who jog more than 30 miles a week may all show this effect.