Kallmann's syndrome: is it always for life?

OBJECTIVE Kallmann's syndrome (KS) is defined by the association of olfacto ry deficit with irreversible, congenital gonadotrophin deficiency (IHH). We present evidence for the existence of a variant form of KS, in which endog enous 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 underdiagnosed. Once full virilization has been induced, ma les with congenital gonadotrophin deficiency whose testes have significantl y increased in size should be reassessed, off androgen replacement therapy, to identify those who no longer require treatment.