Induction of puberty with human chorionic gonadotropin (hCG) followed by reversal of hypogonadotropic hypogonadism in Kallmann syndrome.

INTRODUCTION: Kallmann syndrome (KS) is a rare, congenital disorder combining hypogonadotropic hypogonadism (HH) due to GnRH-deficiency with anosmia. Traditionally thought to require lifelong therapy it turns out to be a reversible condition in some patients.

CASE REPORT: We present a case of a 22-year old man with absent puberty due to KS, in whom genetic testing revealed heterozygosity for a mutation in the PROK2 gene. Pubertal development and virilisation was achieved by using human chorionic gonadotropin (hCG) injections followed by testosterone replacement. During the follow-up we observed reversal of hypogonadism allowing discontinuation of testosterone treatment. Normalisation of testicular volume as well as gonadotropin and inhibin B levels through a 2-year postreversal period was seen.

CONCLUSIONS: Treatment with hCG is effective in inducing pubertal development and may have advantage over testosterone replacement due to a potential of gonadal maturation. A regular assessment of testicular volume and biochemical surveillance including measuring of serum inhibin B and gonadotropins are necessary for a timely detection of reversal of GnRH deficiency.