Obstetric complication-associated ANXA5 promoter polymorphisms may affect gene expression via DNA secondary structures.

Recent findings have highlighted the possibility that polymorphisms within the annexin A5 gene (ANXA5) promoter contribute to the etiology of various obstetric complications. However, the underlying mechanisms are unknown. The M2 haplotype of the ANXA5 shows lower activity and less expression of ANXA5 mRNA. This gene promoter region has a motif that potentially forms a G-quadruplex structure. In vitro G-quadruplex propensity estimated by circular dichroism indicated that the M2 haplotype oligonucleotide manifested a decreased potential for G-quadruplex formation. In addition, in vivo G-quadruplex formation of the promoter region was evidenced by the presence of single-stranded DNA shown by sodium bisulfite treatment of placental genomic DNA. Comparative analysis indicated less potential in the M2 allele than the major allele. Promoter activity of the two haplotypes determined by luciferase reporter analysis correlated with the estimated G-quadruplex propensity. Our data lend support to the developing paradigm that genomic variation affects gene expression levels via DNA secondary structures leading to the disease susceptibility.

Molecular basis of maternal age-related increase in oocyte aneuploidy.

Aneuploidy is one of the most common and serious pregnancy complications in humans. Most conceptuses with autosomal aneuploidy die in utero, resulting in early pregnancy loss. However, some fetuses with aneuploidy survive to term but suffer from disorders associated with congenital anomalies and mental retardation, such as Down syndrome with trisomy 21. Three general characteristics of this condition are well acknowledged: (i) in most cases the extra chromosome is of maternal origin; (ii) most cases are derived from a malsegregation event in meiosis I; and (iii) the frequency of these errors increases with maternal age. The basis for the age-dependent increase in meiosis I errors has been a long-standing enigma. Many investigators have addressed the nature of this biological phenomenon through genomic analyses of extra chromosome 21 using polymorphic markers to determine the frequency or location of crossovers that should ensure faithful chromosome segregation. Cytogenetic analyses of in vitro unfertilized oocytes have also been performed. However, no definitive conclusions regarding meiosis I errors have yet been reached from such studies. Recent findings in conditional knock-out mice for meiosis-specific cohesin have shed further light on this issue. The present review focuses on the current understanding of age-related aneuploidy and provides an overview of the mechanisms involved. We refer to recent data to illustrate some of the new paradigms that have arisen in this field.

Polymorphisms in the annexin A5 gene promoter in Japanese women with recurrent pregnancy loss.

Recent findings have raised the possibility that polymorphisms within the annexin A5 gene (ANXA5) promoter contribute to the etiology of recurrent pregnancy loss (RPL). In our present study, 243 Japanese women who had suffered more than three fetal losses and a group of 119 fertile controls were genotyped for four ANXA5 gene promoter single-nucleotide polymorphisms (SNPs; SNP1-4: g.-467G >A, g.-448A>C, g.-422T>C, g.-373G>A) previously reported to be associated with this disorder. An additional two SNPs located within the 5'-untranslated region of the ANXA5 (SNP5 and 6: g.-302T>G, g.-1C>T) were also evaluated. Our case--control study revealed that the minor allele was significantly more frequent in the RPL group than controls for all six of these SNPs, among which SNP5 showed the highest significance (P= 0.002). As with the M2 haplotype for SNP1-4 (A-C-C-A) for a western population in previous reports, a haplotype comprising all of the minor alleles for SNP1-6 (A-C-C-A-G-T), the third major haplotype in the Japanese population, showed a significantly higher frequency in our current RPL subjects than in controls (P= 0.025). In addition, the second major haplotype (G-A-T-G-G-C) was found to confer a significant risk of RPL (P= 0.036), implicating SNP5 as a major risk determinant for this disease. Our present findings support the hypothesis that genomic variations within the ANXA5 gene upstream region impact upon the disease susceptibility to RPL. Our data indicate that SNP5 is a novel risk factor for this disease in the Japanese population.

Bilateral interruption of mid-fallopian tubes and ovarian anomalies including ectopic ovary and cystic teratoma, a previously unreported combination.

A 25-year-old infertile woman underwent laparoscopy because of a dermoid cyst of the left ovary and was found to have an ectopic ovary, to which an abnormal right fimbria was connected, with an isolated right ovary in the normal position and the bilateral segmental absence of the middle portion of the fallopian tubes. The complex of these anomalies is rare. A fundamental error might have existed in the mesenchyme of the gonadal ridges of the early embryo, rather than the epithelial origin of the müllerian and wolffian ducts.

Genetic variation in the indoleamine 2,3-dioxygenase gene in pre-eclampsia.

PROBLEM: To investigate the contribution of genomic variations in the indoleamine 2,3-dioxygenase (IDO) gene to the onset of pre-eclampsia. METHOD OF STUDY: We examined sequence variations in the IDO1 gene using placental genomic DNA from 35 pre-eclamptic patients and 32 normotensive pregnant women. RESULTS: A case-control study revealed that none of the common variants influences the risk of disease. Sequencing of each IDO1 exon in diseased subjects revealed rare variants. This variation, c.-147_150delGAAA, was located within the 5'-untranslated region of the IDO1 gene, and its homozygote was identified only in pre-eclamptic subjects. However, despite the low levels of IDO expression and enzyme activity in the c.-147_150delGAAA homozygote, reporter assays indicated that this variation does not affect gene expression. CONCLUSION: Our findings indicate that genetic alteration of fetal IDO gene does not appear to be a primary cause of pre-eclampsia.

CD9 gene variations are not associated with female infertility in humans.

BACKGROUND/AIMS: To determine whether genetic alterations in the CD9 gene are associated with female infertility in humans. METHODS: We sequenced the entire coding region of this gene in 86 Japanese women with unexplained infertility and further conducted a case-control study of six tagging single nucleotide polymorphisms (SNPs) in this gene using an additional 164 samples obtained from a fertile control group. RESULTS: No disease-causing mutation in the CD9 gene was evident in these samples and no significant association between the tagging SNPs and the studied cohort was identified. CONCLUSIONS: Our findings do not support the hypothesis that genetic alterations of the CD9 gene cause female infertility in humans.

Mutations of the SYCP3 gene in women with recurrent pregnancy loss.

Aneuploidy, a chromosomal numerical abnormality in the conceptus or fetus, occurs in at least 5% of all pregnancies and is the leading cause of early pregnancy loss in humans. Accumulating evidence now suggests that the correct segregation of chromosomes is affected by events occurring in prophase during meiosis I. These events include homologous chromosome pairing, sister-chromatid cohesion, and meiotic recombination. In our current study, we show that mutations in SYCP3, a gene encoding an essential component of the synaptonemal complex that is central to the interaction of homologous chromosomes, are associated with recurrent pregnancy loss. Two out of 26 women with recurrent pregnancy loss of unknown cause were found to carry independent heterozygous nucleotide alterations in this gene, neither of which was present among a group of 150 fertile women. Analysis of transcripts from minigenes harboring each of these two mutations revealed that both affected normal splicing, possibly resulting in the production of C-terminally mutated proteins. The mutant proteins were found to interact with their wild-type counterpart in vitro and inhibit the normal fiber formation of the SYCP3 protein when coexpressed in a heterologous system. These data suggest that these mutations are likely to generate an aberrant synaptonemal complex in a dominant-negative manner and contribute to abnormal chromosomal behavior that might lead to recurrent miscarriage. Combined with the fact that similar mutations have been previously identified in two males with azoospermia, our current data suggest that sexual dimorphism in response to meiotic disruption occurs even in humans.

Efficacy of selective venous catheterization in localizing a small androgen-producing tumor in ovary.

BACKGROUND: Androgen-producing tumors, originating mostly in the ovary or adrenal gland, induce hirsutism. It sometimes is difficult to localize the tumor precisely even with modern imaging technology. We used selective venous catheterization and hormonal sampling (SVCHS) to localize an androgen-producing ovarian tumor. CASE REPORT: A 37-year-old woman (gravida 0, para 0) presented with secondary amenorrhea, infertility, and virilization, including hirsutism and progressive balding. Laboratory examination revealed severe hyperandrogenism, with a total testosterone (T) concentration of 13.1 ng/ml and a free T concentration of 28.1 pg/ml. Dehydroepiandrosterone sulfate and androstendione were within normal ranges. Work-up included an abdominal and pelvic ultrasound scan, CT, MRI, and norcholesterol scintigraphy without discovery of the source of the hyperandrogenism. Persistently high plasma T concentrations prompted SVCHS. Eleven blood samples were collected from both the adrenal and the ovarian veins bilaterally. The total T concentration was significantly higher in blood from the right ovarian vein (878 ng/ml). A laparoscopic right oophorectomy was performed. The pathologic diagnosis was a Leydig cell tumor. A rapid decrease in free and total T followed tumor removal, and she became pregnant by in vitro fertilization. CONCLUSIONS: SVCHS is highly effective in confirming the presence of a small androgen-producing ovarian tumor.

High recurrence rate of uterine fibroids on transvaginal ultrasound after abdominal myomectomy in Japanese women.

AIM: To evaluate the recurrence rate of uterine fibroids (UF) after abdominal myomectomy and the risk factors for recurrences. METHODS: In a retrospective study, transvaginal ultrasound examinations were performed in 135 women after abdominal myomectomy. The main outcome measures were cumulative UF recurrence rates after abdominal myomectomy. The Kaplan-Meier survival analysis was used to estimate the cumulative recurrence rate, and log-rank tests were applied to compare survival curves among different categorical groups of potential risk factors for recurrences. RESULTS: The cumulative UF recurrence rates at 12 and 24 months after abdominal myomectomy were 12.4 and 46.0%, respectively. Women who had a history of previous myomectomy had a higher hazard of UF recurrence than women without such a history (hazard ratio 4.1, 95% confidence interval 1.20-13.6). The women having four or more UFs had a higher hazard than those who had less than four UFs (hazard ratio 3.7, confidence interval 1.41-9.88). After adjusting these variables to each other, the hazard ratio remained similar. CONCLUSIONS: The UF recurrence rate detected by transvaginal ultrasound after abdominal myomectomy was high, but did not require any additional surgery. Physicians need to consider the timing of the myomectomy, taking into account complications of pregnancy and infertility due to UF recurrence.