Kallmann's syndrome: is it always for life?

OBJECTIVE: Kallmann's syndrome (KS) is defined by the association of olfactory deficit with irreversible, congenital gonadotrophin deficiency (IHH). We present evidence for the existence of a variant form of KS, in which endogenous gonadotrophin secretion recovers spontaneously in later life.

DESIGN: Longitudinal clinical study.

PATIENTS: Five men with anosmia or severe hyposmia, who originally presented in their late teens or early twenties as a result of severe pubertal delay and were thus presumed to have KS.

RESULTS: Spontaneous onset of endogenous gonadotrophin secretion, evidenced by progressive normalization of testicular volume and of serum testosterone concentration, occurred in these men over a period of years following the initial diagnosis.

CONCLUSIONS: This variant form of Kallman's syndrome is not well recognized and may well be under-diagnosed. Once full virilization has been induced, males with congenital gonadotrophin deficiency whose testes have significantly increased in size should be reassessed, off androgen replacement therapy, to identify those who no longer require treatment.