PATIENTS WITH IDIOPATHIC HYPOGONADOTROPIC HYPOGONADISM HAVE NORMAL GONADOTROPIN-RELEASING-HORMONE GENE STRUCTURE

Study Objective: To determine if the exons encoding the structural pro tein for gonadotropin-releasing hormone (GnRH) are present in patients with idiopathic hypogonadotropic hypogonadism (IHH), and whether indi vidual exons possess smaller mutations not detected previously. Design : Study of patients with IHH by DNA analysis using polymerase chain re action (PCR) and DNA sequencing. Setting: Laboratories of the Departme nt of Obstetrics and Gynecology, Department of Oral Biology, Medical C ollege of Georgia. Participants: Fifteen well-characterized patients ( 13 females and 2 males) presenting with delayed puberty due to IHH and two fertile controls. Interventions: DNA extraction from all individu als for the performance of PCR and DNA sequencing for exon II, the cod ing region for the GnRH decapeptide. Main Outcome Measures: For PCR an alysis, fragment sizes were evaluated on agarose gels stained with eth idium bromide in the presence of a molecular weight marker. Specific n ucleotide sequences were determined from radiographs of DNA sequencing gels. Results: Each of the fragments containing exons II-IV of the Gn RH gene were present and of normal size in all patients with IHH and c ontrols. Exon II and splice junction sequences were normal in four fem ales with IHH. Conclusions: PCR of individual exons encoding the struc tural gene for GnRH is normal in 15 patients with IHH. DNA sequencing of exon II in four women with IHH is normal. PCR analysis and prelimin ary DNA sequencing fail to demonstrate causative mutations in the GnRH gene in our patients with IHH, which contributes additional informati on not provided by Southern analysis and previous studies.