Hypogonadotropic Hypogonadism and Anosmia (Kallmann's Syndrome) Associated with a Marker Chromosome

A patient with hypogonadotropic hypogonadism and anosmia (Kallmann's syndrome) had an associated chromosomal abnormality. Evaluation of the hypothalamic pituitary axis showed undetectable basal LH and FSH and slight increases in both gonadotropins in response to GnRH. Augmented gonadotropin response to GnRH after serial subcutaneous injections of GnRH confirmed a hypothalamic defect. Additional endocrine tests failed to reveal other hormone dysfunctions. A supernumerary chromosome was detected by routine chromosome analysis. The extra genetic material was identified by differential cytogenetic banding procedures as an accessory bisatellited marker chromosome originating from either chromosome group D or G. Chromosome analyses of both parents were normal. Our results suggest that, in at least some cases, the Kallmann's phenotype may be associated with a chromosome abnormality.