Mutation analysis of the gonadotropin-releasing hormone receptor gene in idiopathic hypogonadotropic hypogonadism

OBJECTIVE

To determine if GnRH receptor mutations occur in patients with idiopathic hypogonadotropic hypogonadism.

DESIGN

Patients and controls were studied by molecular genetic analysis.

SETTING

A tertiary medical center setting.

PATIENT(S)

Twenty-four patients with idiopathic hypogonadotropic hypogonadism and 20 controls.

INTERVENTION(S)

Deoxyribonucleic acid from all individuals was analyzed by Southern blot analysis and denaturing gradient gel electrophoresis. Genomic DNA was digested with restriction enzymes, and Southern blots and denaturing gradient gel blots were constructed. Blots were hybridized with the GnRH receptor complementary DNA probe. The DNA sequencing was performed on samples from two representative patients.

MAIN OUTCOME MEASURE(S)

Gonadotropin-releasing hormone receptor gene structure was ascertained by comparing fragments from autoradiographs in patients and controls. Individual nucleotides were ascertained from DNA sequencing gels.

RESULT(S)

No GnRH receptor gene deletions or polymorphisms were identified by Southern blot analysis. New restriction-fragment melting polymorphisms using the enzymes DpnII, RsaI, and HaeIII were identified by denaturing gradient gel blots in patients and controls.

CONCLUSION(S)

Gonadotropin-releasing hormone receptor gene deletions or rearrangements were not observed in our idiopathic hypogonadotropic hypogonadism patients. Denaturing gradient gel electrophoresis failed to identify single-base differences unique to patients with idiopathic hypogonadotropic hypogonadism, dramatically reducing the likelihood that point mutations of the GnRH receptor gene are present in idiopathic hypogonadotropic hypogonadism.

Human chorionic gonadotrophin-beta gene sequences in women with disorders of HCG production

Women with recurrent abortion, primary unexplained infertility, and gestational trophoblastic neoplasia (GTN) manifest disordered human chorionic gonadotrophin (HCG) secretion. Mutations in the HCG beta/luteinizing hormone (LH) beta gene complex could cause aberrant HCG production in these disorders. The purpose of this study was to determine whether HCG beta gene deletions occur in women with recurrent abortion or primary unexplained infertility, and whether HCG beta gene duplications are present in women with GTN. DNA was extracted from 10 patients with unexplained recurrent abortion, 10 patients with unexplained primary infertility, 12 patients with GTN, three partners of women with GTN, and 30 controls. Southern blots were constructed and hybridized with DNA probes for HCG beta-5 and the LH beta gene. No gene deletions were identified in patients with recurrent abortion or primary unexplained infertility. Likewise, no gene duplications were identified in women with GTN. A previously described Mbol restriction fragment length polymorphism (RFLP) was identified in both patients and controls. A new Pstl RFLP was also characterized, but was present in patients and controls. Deletion/duplication mutations in the HCG beta/LH beta gene complex do not appear to be common causes of aberrant HCG production in humans with these disorders.

The follicle-stimulating hormone receptor gene is polymorphic in premature ovarian failure and normal controls

OBJECTIVE

To examine the FSH receptor gene for detectable abnormalities in women with premature ovarian failure.

DESIGN

Study of genomic DNA from controls and from patients with 46,XX premature ovarian failure (POF).

SETTING

Clinics and laboratories of university gynecology and obstetrics departments.

PATIENTS

Twenty-one women with 46,XX POF and 40 normal fertile controls.

INTERVENTIONS

Deoxyribonucleic acid was analyzed in patients and controls by Southern blot analysis, polymerase chain reaction (PCR), and denaturing gradient gel electrophoresis. Southern blots were hybridized with the FSH receptor complementary DNA and other smaller DNA probes. Exons 1, 5 to 6, and 10 were amplified by PCR and electrophoresed on agarose gels. Polymerase chain reaction products from exons 1 and 10 were electrophoresed on denaturing gradient gels.

MAIN OUTCOME MEASURES

Fragments obtained by Southern blot analysis and PCR were compared in patients and controls. Polymerase chain reaction fragments electrophoresed on denaturing gels also were compared in patients and controls.

CONCLUSIONS

No FSH receptor gene deletions or other mutations were identified in women with POF. Southern blots containing PstI- and HindIII-digested DNA revealed restriction fragment length polymorphisms in both patients and controls. Denaturing gradient gel electrophoresis analysis of PCR fragments of exon 10 also demonstrated DNA sequence polymorphisms in both patients and controls. Follicle-stimulating hormone receptor gene deletions are not common in women with POF, although the gene is polymorphic. We cannot exclude point mutations in other regions of the FSH receptor gene in some patients with POF.