Human gene mutations causing infertility

The identification of gene mutations causing infertility in humans remains noticeably deficient at present. Although most males and females with infertility display normal pubertal development, nearly all of the gene mutations in humans have been characterised in people with deficient puberty and subsequent infertility. Gene mutations are arbitrarily categorised into four different compartments (I, hypothalamic; II, pituitary; III, gonadal; and IV, outflow tract). Diagnoses of infertility include hypogonadotrophic hypogonadism (compartments I and II), hypergonadotrophic hypogonadism (III), and obstructive disorders (compartment IV). Most gene mutations identified to date affect gonadal function, but it is also apparent that a large number of important genes in normal fertility have yet to be realised.

Familial gonadotropin-releasing hormone resistance and hypogonadotropic hypogonadism in a family with multiple affected individuals

OBJECTIVE

To characterize the phenotype of idiopathic hypogonadotropic hypogonadism due to compound heterozygous GnRHR gene mutations (Arg262Gln/Tyr284Cys).

DESIGN

Retrospective review.

SETTING

Tertiary medical center.

PATIENT(S)

Family containing four siblings (three female and one male) with complete idiopathic hypogonadotropic hypogonadism.

INTERVENTION(S)

Baseline and stimulated laboratory studies. One patient received GnRH treatment and one received human menopausal gonadotropins.

MAIN OUTCOME MEASURE(S)

Clinical phenotype vs. genotype is assessed by endocrine studies, karyotype, pedigree, and review of pathology slides of ovarian neoplasm.

RESULT(S)

With GnRH stimulation, two patients with idiopathic hypogonadotropic hypogonadism had maximum LH < 10 mIU/mL, and two others had peak LH > 10 mIU/mL. With repeated GnRH stimulation 24 hours later, gonadotropin levels in all patients were increased. Stimulation of thyroid-releasing hormone and tests for insulin-induced hypoglycemia were normal. One affected patient did not ovulate after GnRH treatment, but her sister ovulated with gonadotropin treatment. Another affected sibling had bilateral oophorectomy for seromucinous cystadenomas, and her hypogonadotropic state remained after castration. The man with idiopathic hypogonadotropic hypogonadism and his unaffected brother had a ring chromosome 21.

CONCLUSION(S)

All patients with complete idiopathic hypogonadotropic hypogonadism had the same GnRHR mutations, but clinical presentations and endocrinologic responses were heterogeneous. Gonadotropin levels remained low in patients with idiopathic hypogonadotropic hypogonadism after castration, and ring chromosome 21 was present, suggesting that sequences from this chromosome could affect the idiopathic hypogonadotropic hypogonadism phenotype.

Mutations in the follicle-stimulating hormone-beta (FSH beta) and FSH receptor genes in mice and humans

Follicle-stimulating hormone (FSH), a dimeric glycoprotein synthesized in the anterior pituitary gland, is important for the production of sex steroids and gametes. FSH-beta (FSH beta) and FSH receptor (FSHR) knockout mice display impaired ovarian follicular development and infertility in females and small testes, oligospermia, and fertility in males. Humans with FSH beta gene mutations tend to have a more severe phenotype than those with FSHR gene mutations, although infertility and varying degrees of impaired sex steroid production occur in both types of mutations. Data from human and mouse mutations in the FSH beta and FSHR genes suggest that FSH is necessary for normal pubertal development and fertility in males and females.

Essential genetics for the obstetrician/gynecologist

The science of genetics has become increasingly important in the practice of medicine. This article reviews the practical, clinical aspects of genetics relevant to obstetrics and gynecology. The basic fundamentals of molecular biology techniques currently used in DNA diagnostic tests are discussed.

Use of denaturing gradient gel blots to screen for point mutations in the factor VIII gene

Denaturing gradient gel electrophoresis (DGGE) is commonly used to search for point mutations in DNA fragments amplified in vitro by the polymerase chain reaction (PCR). For the complete detection of mutations in large genes with many exons, the DGGE-PCR approach, or any other PCR-based method, requires many primer sets and amplification reactions to scan the entire protein-coding sequence. We previously demonstrated that DGGE analysis using DNA blots detects mutations in Drosophila genes and sequence polymorphisms in human genes without prior PCR amplification. To determine if human point mutations could be detected using denaturing gradient gels (DGG blots), genomic DNA samples from hemophilia A families were analyzed for mutations in the factor VIII (FVIII) gene. Restriction enzyme digested DNA samples were subjected to DGGE and transferred to nylon blots. Hybridization of the DGG blots with FVIII cDNA probes revealed mutant and polymorphic DNA sequence differences. Among 26 affected families that were not carriers of intron 22 inversion mutations, 18 family-specific DNA fragment polymorphisms and one multiexon deletion were mapped. DNA sequencing of eight patient-specific polymorphic DNA fragments revealed six single base change mutations, one 4 bp deletion, and one 13 bp duplication.

Mutations of follicle stimulating hormone-beta and its receptor in human and mouse: genotype/phenotype

The pituitary gonadotropin follicle stimulating hormone (FSH) interacts with its membrane-bound receptor, to produce biologic effects. Traditional functions of FSH include, follicular development and estradiol production in females and the regulation of Sertoli cell action and spermatogenesis in males. FSHbeta knock-out mice and transgenic mice, serve as models for FSH deficiency and excess, respectively. In addition, mutations of both FSHbeta and FSHR genes have been characterized in humans, although phenotypic effects of the ligand appear to be more profound than those of its receptor. FSH is essential for normal puberty and fertility in females, particularly ovarian follicular development beyond the antral stage. In males, FSH is necessary for normal spermatogenesis and when FSH function is completely absent, infertility occurs. With partial FSH deficiency in males, spermatogenesis is affected, but fertility may still be possible. FSH may also be necessary for normal androgen synthesis in males and females.

Genetics of human hypogonadotropic hypogonadism

Humans with hypogonadotropic hypogonadism (HH) manifest irreversible pubertal delay, infertility, and low serum levels of follicle-stimulating hormone (FSH) and luteinizing hormone (LH). Although the genetic basis of this condition is largely unknown, mutations have been identified in approximately 5-10% of HH patients. Mutations in the KAL gene (Kallmann syndrome) and the AHC gene (adrenal hypoplasia congenita/HH) cause X-linked recessive HH. Autosomal recessive HH may be brought about by mutations in the gonadotropin-releasing hormone receptor, leptin, and the leptin receptor genes. Isolated deficiencies of the gonadotropins FSH and LH are due to corresponding beta-subunit genes. PROP1 gene mutations lead to combined pituitary deficiency, and HESX gene mutations result in septo-optic dysplasia, both of which include HH. These identified gene mutations advance our understanding of normal hypothalamic-pituitary-gonadal function.

Genetics of human hypogonadotropic hypogonadism

Humans with hypogonadotropic hypogonadism (HH) manifest irreversible pubertal delay, infertility, and low serum levels of follicle-stimulating hormone (FSH) and luteinizing hormone (LH). Although the genetic basis of this condition is largely unknown, mutations have been identified in approximately 5-10% of HH patients. Mutations in the KAL gene (Kallmann syndrome) and the AHC gene (adrenal hypoplasia congenita/HH) cause X-linked recessive HH. Autosomal recessive HH may be brought about by mutations in the gonadotropin-releasing hormone receptor, leptin, and the leptin receptor genes. Isolated deficiencies of the gonadotropins FSH and LH are due to corresponding beta-subunit genes. PROP1 gene mutations lead to combined pituitary deficiency, and HESX gene mutations result in septo-optic dysplasia, both of which include HH. These identified gene mutations advance our understanding of normal hypothalamic-pituitary-gonadal function.

Mutational analysis of DAX1 in patients with hypogonadotropic hypogonadism or pubertal delay

Although delayed puberty is relatively common and often familial, its molecular and pathophysiologic basis is poorly understood. In contrast, the molecular mechanisms underlying some forms of hypogonadotropic hypogonadism (HH) are clearer, following the description of mutations in the genes KAL, GNRHR, and PROP1. Mutations in another gene, DAX1 (AHC), cause X-linked adrenal hypoplasia congenita and HH. Affected boys usually present with primary adrenal failure in infancy or childhood and HH at the expected time of puberty. DAX1 mutations have also been reported to occur with a wider spectrum of clinical presentations. These cases include female carriers of DAX1 mutations with marked pubertal delay and a male with incomplete HH and mild adrenal insufficiency in adulthood. Given this emerging phenotypic spectrum of clinical presentation in men and women with DAX1 mutations, we hypothesized that DAX1 might be a candidate gene for mutation in patients with idiopathic sporadic or familial HH or constitutional delay of puberty. Direct sequencing of DAX1 was performed in 106 patients, including 85 (80 men and 5 women) with sporadic HH or constitutional delay of puberty and patients from 21 kindreds with familial forms of these disorders. No DAX1 mutations were found in these groups of patients, although silent single nucleotide polymorphisms were identified (T114C, G498A). This study suggests that mutations in DAX1 are unlikely to be a common cause of HH or pubertal delay in the absence of a concomitant history of adrenal insufficiency.

Mutation analysis of the EMX2 gene in Kallmann's syndrome

OBJECTIVE

To investigate the possibility that a mutation in the human EMX2 gene may be involved in Kallmann's syndrome.

DESIGN

In vitro experiment.

SETTING

Academic Medical Center.

PATIENTS

One hundred and twenty patients with Kallman's syndrome or idiopathic hypogonadotrophic hypogonadism (IHH).

INTERVENTION

Peripheral blood leukocytes were used to obtain DNA.

MAIN OUTCOMES MEASURES

Single-stranded conformational polymorphism (SSCP) analysis was used to identify possible mutations of the EMX2 gene.

RESULTS

One hundred and twenty patients with Kallmann's syndrome or IHH, had no mutations noted in this gene.

CONCLUSION

It is unlikely that EMX2 mutations are a clinically significant cause of IHH or Kallman's syndrome.

The molecular basis of human hypogonadotropic hypogonadism

Patients with hypogonadotropic hypogonadism (HH) present with delayed puberty, infertility, and low serum gonadotropins. The molecular basis for most cases of HH is unknown, but single gene mutations have been described for some hypothalamic and pituitary genes. Kallmann syndrome due to KAL gene mutations and adrenal hypoplasia congenita/HH caused by AHC gene mutations are both X-linked recessive disorders. Mutations in the gonadotropin releasing hormone receptor, leptin, and the leptin receptor cause autosomal recessive HH. In addition, isolated deficiencies of follicle stimulating hormone and luteinizing hormone in the corresponding specific beta-subunit genes and PROP1 gene mutations represent pituitary deficiency states, resulting in a phenotype of HH. Despite these remarkable advances in our understanding of human HH, the cause of approximately 90% remains unknown.

Molecular analysis of the gonadotropin-releasing hormone receptor in patients with polycystic ovary syndrome

OBJECTIVE

To determine whether a mutation in the GnRH receptor gene is responsible for polycystic ovary syndrome (PCOS).

DESIGN

Molecular analysis of human genomic DNA.

SETTING

Academic research environment.

PATIENT(S)

Eighty patients with PCOS.

INTERVENTION(S)

Extraction and polymerase chain reaction (PCR) analysis of genomic DNA, confirmation of PCR products by ethidium bromide staining of agarose gels after electrophoresis, denaturing gradient gel electrophoresis of PCR products, and photography.

MAIN OUTCOME MEASURE(S)

Mutations in the GnRH receptor of women with PCOS.

RESULT(S)

Denaturing gradient gel electrophoresis revealed no mutations in the exonic sequence encoding the open reading frame of the GnRH receptor.

CONCLUSION(S)

A mutation in the GnRH receptor gene is unlikely to be the underlying cause of PCOS in most patients. The molecular basis of this disorder remains unknown.

Mutations in human gonadotropin genes and their physiologic significance in puberty and reproduction

OBJECTIVE

Human gene mutations provide an opportunity to study the pathophysiology of the disease process as well as normal physiology. The purpose of the present report was to review known human gene mutations that affect gonadotropin secretion.

DESIGN

A retrospective analysis of studies of human gene mutations that affect hypothalamic, pituitary, and gonadal function was conducted.

RESULT(S)

Mutations have been identified for at least three genes that cause inherited hypogonadotropic hypogonadism. In addition, gene mutations for the beta-subunits of FSH and LH have been characterized. Both activating and inactivating mutations have been identified for the gonadotropin receptor genes.

CONCLUSION(S)

The identification of human gene mutations has furthered our understanding of the normal processes of pubertal development and fertility.

Administration of progesterone before oocyte retrieval negatively affects the implantation rate

OBJECTIVE

To compare the efficacy of two clinically accepted methods of progesterone supplementation during IVF.

DESIGN

Prospective randomized trial.

SETTING

A university-based IVF program.

PATIENT(S)

Three hundred fourteen stimulated IVF cycles between January 1993 and October 1994.

INTERVENTION(S)

Patients were assigned to one of two luteal phase progesterone regimens by a random permuted block design. In protocol A, 12.5 mg of IM progesterone was given 12 hours before oocyte retrieval; in protocol B, 25 mg of IM progesterone was given on the day of oocyte retrieval.

MAIN OUTCOME MEASURE(S)

Clinical pregnancy.

RESULT(S)

Patient demographic characteristics, including age, diagnosis, number of oocytes retrieved and fertilized, and number of embryos transferred, were not different between the two groups. There was no difference in the rate of cycle cancellation between the groups. One hundred forty ETs were performed in patients assigned to protocol A and 142 in patients assigned to protocol B. The clinical pregnancy rate in group A was 12.9% compared with 24.6% in group B.

CONCLUSION(S)

The administration of progesterone before oocyte retrieval is associated with a lower pregnancy rate than the administration of progesterone after oocyte retrieval.

The Finnish follicle-stimulating hormone receptor gene mutation is rare in North American women with 46,XX ovarian failure

OBJECTIVE

To determine whether FSH receptor gene missense mutation in Finnish women with premature ovarian failure (POF) is present in North American women with POF.

DESIGN

Analysis of DNA from patients and controls.

PATIENT(S)

Thirty-five women with POF and ten normal controls.

INTERVENTION(S)

Extraction of DNA with subsequent digestion by the enzyme BsmI, polyacrylamide gel electrophoresis, ethidium bromide staining, and photography.

MAIN OUTCOME MEASURE(S)

After restriction enzyme digestion, the frequencies of the normal allele (two fragments of 51 and 27 base pairs) and the mutant allele (a single 78-base pair fragment) were determined.

RESULT(S)

BsmI digestion was noted for all 35 affected individuals and 10 controls, thus demonstrating homozygosity for the normal FSH receptor allele. No patient or control was heterozygous or homozygous for the mutant allele.

CONCLUSION(S)

The missense mutation in the human FSH receptor gene in Finnish women with POF is uncommon in North American women with POF. The molecular basis of ovarian failure for most patients remains unknown.

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.

Failed fertilization after intracytoplasmic sperm injection: the extent of paternal and maternal chromatin decondensation

OBJECTIVE

To determine the extent of paternal and maternal chromatin decondensation in unfertilized eggs after intracytoplasmic sperm injection (ICSI).

DESIGN

Eggs that failed to show two pronuclei (2-PN) 48 hours after ICSI were studied at two different time intervals: at ICSI program inception (group A) and after 8 months (group B).

PATIENT(S)

Forty-nine patients undergoing IVF cycles.

MAIN OUTCOME MEASURE(S)

The unfertilized eggs were studied by chromatin staining.

RESULT(S)

The average fertilization rate from all ICSI cycles in these two groups was 45%. The fertilization rates in groups A and B were 35% and 59%, respectively. In group A, 65% of the unfertilized eggs were characterized by condensed sperm chromatin with 11% showing partial decondensation. In group B, only 28% of the unfertilized eggs demonstrated condensed sperm chromatin, whereas 45% were partially decondensed. In these two groups, no sperm chromatin was detected in 24% of the unfertilized eggs. The maternal chromatin remained at metaphase II in 84% of all unfertilized eggs analyzed.

CONCLUSION(S)

These observations suggest that the technical problem of deposition of the sperm inside the egg is not the major cause of failure of fertilization rates in ICSI cycles. Rather, it is likely to be the failure to complete both the maternal and paternal chromatin transitions that occur with normal fertilization.

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.

Relevance of molecular medicine to clinical obstetrics and gynecology

Understanding molecular biology can improve the clinical acumen of the practicing obstetrician/gynecologist. An area of basic research now becoming clinically relevant involves the G proteins and G protein-coupled receptors. Clinicians already manipulate G protein-coupled receptors in their daily practice. Examples include the administration of oxytocin (oxytocin receptors), beta-2 tocolytic agents (beta 2-adrenergic receptors), GnRH agonists (GnRH receptors), exogenous gonadotropins (FSH and LH receptors), and bromocriptine (dopamine receptor). Clinically important disorders presenting to the obstetrician/gynecologist include some forms of precocious puberty, delayed puberty, premature ovarian failure, and pituitary adenomas which are due to mutations of G proteins and G protein-coupled receptors. The importance of these proteins is demonstrated by the fact that G protein-related genes comprise about 1 percent of the human genome. Additionally, the knowledge that some G protein gene mutations are present in the germ line, and others are somatic cell in origin (and not heritable), aids in more accurate genetic counseling to patients.

Molecular biology in reproductive endocrinology

Through the study of naturally occurring mutations in humans, the creation of mutations by site-directed mutagenesis, and the production of transgenic knockout mice, further understanding of molecular reproductive endocrinology had been achieved. Mutations in the aromatase gene in females have confirmed that its deficiency results in a previously unrecognized form of sexual ambiguity with a 46,XX karyotype, and delayed puberty with multicystic ovaries. It has long been known that estrogen is necessary for skeletal growth and epiphyseal closure in the female, but aromatase and estrogen receptor gene mutations in men have demonstrated for the first time, that estrogen is important for epiphyseal closure in the male. Mutations in the steroidogenic acute regulatory protein have been recently described that demonstrate the cause for lipoid congenital adrenal hyperplasia, a disorder characterized by the complete lack of steroid production. New gene mutations in gonadotropin beta-subunits, pituitary hormones, G-protein coupled receptors, G-proteins, steroid enzymes and their receptors have also been characterized recently. Site-directed mutagenesis experiments and transgenic knockout mice have been increasingly used to study the effects of normal endocrine function. Normal functions of steroid receptor genes (steroidogenic factor-1, estrogen receptor, progesterone receptor) the glycoprotein alpha-subunit, luteinizing hormone beta, and proto-oncogenes such as RET have been better characterized by creating knockout models. Molecular biology techniques permit these types of studies which may be difficult, if not impossible, to perform otherwise in physiologic settings.

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.

Ultrasound prediction of follicle volume: is the mean diameter reflective?

OBJECTIVE

To evaluate the relationship between 2 dimensional sonographic measurement of ovarian follicles and their actual volume.

DESIGN

Prospective clinical study.

SETTING

The in vitro fertilization (IVF) program of a University based, tertiary care hospital.

PATIENTS AND INTERVENTIONS

Sonographic categorization by shape, and measurement of 96 individual ovarian follicles immediately prior to aspiration for IVF. Each follicle was aspirated under direct ultrasound guidance and the volume recorded. The 96 follicles were visualized in a total of 14 patients from whom 2 to 27 oocytes were obtained.

MAIN OUTCOME MEASURE

Total volume of each follicle.

RESULTS

Round and polygonal follicles exhibited a highly significant relationship between sonographically measured mean diameter and total follicle volume. The volume of follicles that were categorized as ellipsoid was not predicted by measurement of the longest diameter, shortest diameter or mean diameter.

CONCLUSION

The mean diameter of round and polygonal follicles accurately predicts total follicular volume. However, clinical decisions in ovulation induction should be modified when the follicle shape is predominantly ellipsoid because the traditionally held belief that the sonographic measurement of the follicular diameter correlates with the follicular volume does not apply in those circumstances.

Dicavitary uteri with twin gestation: a case following clomiphene citrate therapy and review of obstetric outcomes

We report the first case of dicavitary twin pregnancy, following clomiphene citrate therapy, in a patient with uterus bicornis bicollis and anovulation. A review of the literature is presented, and obstetric outcomes and management of these rare pregnancies are discussed.

Follicle-stimulating hormone beta gene structure in premature ovarian failure

OBJECTIVE

To determine whether mutations in the gene for FSH beta are present, and possibly etiologic, in some patients with 46,XX premature ovarian failure (POF).

DESIGN

DNA samples obtained from 18 study patients with POF and two menopausal fertile controls were studied by Southern blot analysis. DNA sequencing was performed in one patient.

SETTING

Patients were seen in a reproductive endocrinology clinic and studied in a medical school laboratory setting at the Medical College of Georgia and Tufts University.

MAIN OUTCOME MEASURES

Restriction fragment sizes on autoradiographs were compared between the study group and controls. DNA sequencing radiographs were compared between one study patient and five controls.

RESULTS

Fragment sizes obtained with the restriction enzymes EcoRI, DraI, HincII, PstI, KpnI, BglI, BamHI, and BglII were similar size in both study subjects and controls using the probes pFSH beta-1.4 and pFSH beta-1.2. A previously described HindIII polymorphism was present using pFSH beta-1.2, but HindIII fragment sizes were identical in patients with ovarian failure and controls using pFSH beta-1.4. DNA sequencing of the FSH beta gene in one patient was normal.

CONCLUSIONS

No mutations in the gene for FSH beta were identified in women with POF. DNA sequencing of the exons and promoter region of the FSH beta gene in one woman with POF was normal. This does not entirely exclude the possibility that smaller deletions, insertions, or point mutations of the FSH beta could be etiologic in some women with POF. The HindIII polymorphism does not appear to segregate with 46,XX POF.

Absence of the testicular determining factor gene SRY in XX true hermaphrodites and presence of this locus in most subjects with gonadal dysgenesis caused by Y aneuploidy

OBJECTIVES

The purpose of our study was to discover whether the testicular determining factor gene SRY (sex-determining region on Y) is present or absent in XX true hermaphrodites and in subjects with gonadal dysgenesis caused by Y aneuploidy.

STUDY DESIGN

We screened five XX true hermaphrodites and 24 subjects with gonadal dysgenesis caused by Y aneuploidy for the presence or absence of SRY. With the polymerase chain reaction technique, the sequence coding the 80 amino acid-conserved motif was amplified. The 0.9 kb Hincll pY53.3 subclone, which covers the open reading frame of SRY, serves as a probe for Southern blot analysis.

RESULTS

Test results for all five XX true hermaphrodites were negative for SRY. Conversely, 22 of the 24 individuals with 45,X/46,XY gonadal dysgenesis were positive for SRY, including the 10 subjects with only bilateral streak gonads.

CONCLUSIONS

The absence of SRY in XX true hemaphrodites and the presence of SRY in 10 subjects with 45,X/46,XY constitution who harbored only bilateral streak gonads seem to indicate that multiple genes are involved in gonadal differentiation.

Identification of restriction-fragment length polymorphisms for the human chorionic gonadotropin-beta/luteinizing hormone-beta gene cluster

OBJECTIVE

To determine whether restriction fragment length polymorphisms are present using a deoxyribonucleic acid (DNA) probe for human luteinizing hormone beta subunit (hLH-beta). If the gene for hLH-beta is polymorphic, genetic diagnosis of disorders of luteinizing hormone (hLH) and human chorionic gonadotropin (hCG) production could become possible.

DESIGN

Study of genomic DNA from controls with a variety of restriction enzymes to identify polymorphisms.

SETTING

Laboratories of the Department of Obstetrics and Gynecology, Department of Oral Biology, Medical College of Georgia, Augusta, Georgia.

PATIENTS

Unrelated control men and women seen in clinics at the Medical College of Georgia.

INTERVENTIONS

Genomic DNA was extracted from patients and digested with eight different restriction enzymes for the study of the hLH-beta gene by Southern analysis.

MAIN OUTCOME MEASURE

Fragment (band) sizes on radiographs from Southern blots were compared with those from molecular weight standards.

CONCLUSIONS

Restriction fragment length polymorphisms were identified for four of the restriction enzymes, DraI, HincII, MboI, and KpnI. These polymorphisms may be useful in the diagnosis of disorders of hLH and hCG production.

Gonadotropin-releasing hormone-associated peptide gene sequences in women with hyperprolactinemia

OBJECTIVE

To determine if mutations in the structural gene for gonadotropin-releasing hormone (GnRH)-associated peptide are present in women with hyperprolactinemia.

DESIGN

Patients with hyperprolactinemia and controls were studied retrospectively for GnRH-associated peptide gene mutations.

SETTINGS

Patients seen in a clinical setting were studied at a medical school laboratory setting.

PATIENTS

Fifteen women with hyperprolactinemia and two fertile controls with normal prolactin levels were studied.

INTERVENTIONS

Genomic deoxyribonucleic acid (DNA) was extracted from each patient and subjected to Southern blot analysis and polymerase chain reaction (PCR). For Southern blot analysis, DNA was digested with EcoRI, XbaI, BglII, PstI, and BamHI and hybridized to two DNA probes for GnRH-associated peptide. Exons II to IV, which encode for the structural gene, were amplified by PCR.

MAIN OUTCOME MEASURES

Fragment sizes from autoradiographs were compared among patients and controls. Amplified PCR products of exons II to IV of the GnRH-associated peptide were also compared.

RESULTS

No large deletions, insertions, or polymorphisms were identified in women with hyperprolactinemia or controls by Southern blotting. Each of the exons was present and of normal size by PCR in the study patients and controls.

CONCLUSIONS

No large deletions of the GnRH-associated peptide gene appear to be present in our patients with hyperprolactinemia. Small deletions, insertions, or point mutations are not excluded by this analysis.

Etiologic factors of recurrent abortion and subsequent reproductive performance of couples: have we made any progress in the past 10 years?

OBJECTIVES

We hypothesize that the diagnostic yield and pregnancy outcomes of patients with recurrent abortion have improved over the past 10 years.

STUDY DESIGN

The study was performed in an academic medical center. Diagnoses and outcomes for group A, a published series of 100 patients investigated for recurrent abortion in the section between 1968 and 1977, was compared with those for group B, the 131 patients seen between 1987 and 1991. A standardized protocol was followed, enhanced by new techniques and autoimmune investigations in the latter group. Results were compiled retrospectively. Descriptive statistics and chi 2 analysis were used.

RESULTS

No cause could be found in 37% of patients in group A compared with 24% of couples in group B (p less than 0.05). No clear difference could be shown in the subsequent outcomes of pregnancies.

CONCLUSIONS

Our ability to establish a cause of recurrent abortion has improved slightly over the past 15 years. The gain is not yet reflected in successful pregnancy rates. Multicenter trials are indicated.

Basic concepts of molecular biology as applied to pediatric and adolescent gynecology

Recombinant DNA techniques have increased our understanding of genetic disorders and facilitated their diagnosis and may eventually lead to therapy. Expression may be assessed and quantified by Northern blot analysis, whereas in situ hybridization may localize the transcript. Southern blotting has been the standard method to identify gene mutations and RFLPs, which are useful in the diagnosis of many different disorders. Special multiallelic RFLPs produce a DNA fingerprint particularly useful in paternity testing and forensic medicine. PCR has greatly reduced the time and expense to diagnose genetic disorders, and has an enormous number of applications both clinically and at the research level. These techniques along with DNA sequencing are currently being used in the human genome project, which may some day allow "DNA typing" of individuals for any gene of interest. There is no doubt that new techniques in molecular biology will continue to evolve so that the goal of gene therapy for many disorders may be possible in the future.

Gonadotropin-releasing hormone, follicle-stimulating hormone beta, luteinizing hormone beta gene structure in idiopathic hypogonadotropic hypogonadism

OBJECTIVE

To determine if the genes for gonadotropin-releasing hormone (GnRH), follicle-stimulating hormone beta (FSH beta), and luteinizing hormone beta (LH beta) are present, and if so, whether gene structure is normal in patients with idiopathic hypogonadotropic hypogonadism (IHH).

DESIGN

Patients with clinical and laboratory characteristics of IHH were studied at the deoxyribonucleic acid (DNA) level to assess gene structure.

SETTING

This study took place in an academic setting.

PATIENTS

Human volunteers with documented IHH and fertile controls were studied.

INTERVENTIONS

Genomic DNAs were extracted from each patient, Southern blots were constructed and hybridized to DNA probes for GnRH, FSH beta, and LH beta. DNA samples were also subjected to polymerase chain reaction analysis.

MAIN OUTCOME MEASURES

Gene structure was assessed by analysis of autoradiographs and gel electrophoresis of polymerase chain reaction products in both the study patients and controls.

RESULTS

Each analysis for FSH beta, LH beta, and GnRH demonstrated the same sized fragments in both the study group and control group. A 1.2-kilobase fragment containing the coding region for GnRH was present in all patients with IHH and controls by polymerase chain reaction.

CONCLUSIONS

The genes for GnRH, LH beta, and FSH beta are present in patients with IHH. No large deletions or rearrangements of any of these genes were identified in any of these patients.

The detection of Hind III restriction-fragment length polymorphisms using a deoxyribonucleic acid probe for the beta subunit of follicle-stimulating hormone

Molecular diagnosis of disorders of follicle-stimulating hormone (FSH) production may become possible now that the gene for FSH beta has been characterized. Restriction-fragment length polymorphism (RFLP) analysis provides a means of organized search for molecular variants of FSH. The purpose of this study was to screen controls for the presence of RFLPs using the deoxyribonucleic acid (DNA) probe pFSH beta -1.4. Genomic DNA was digested with 12 different restriction endonucleases; Southern blots were constructed and hybridized to pFSH beta -1.4. No polymorphisms were identified with 11 enzymes. Three of 24 (12.6%) Hind III digests demonstrated a polymorphic fragment of either 5.2, 4.7, or 4.3 kb. These are the first RFLPs identified for the FSH beta gene with pFSH beta -1.4. RFLPs for FSH beta constitute the first step in the molecular analysis of disorders of FSH production.