Deleterious mutations in KAL1 cause X-linked Kallmann syndrome, characterized by hypogonadotropic hypogonadism and anosmia (43), but there are no previous data supporting that minor alterations in the function of KAL1 are associated with sex steroid levels. This evidence concerns the gene ANOS1 and hypogonadotropic hypogonadism 1 with or without anosmia.