Prospective assessment of fetal-maternal cell transfer in miscarriage and pregnancy termination

BACKGROUND Fetal cells (microchimerism) are acquired by women during pregnancy. Fetal microchimerism persists decades later and includes cells with pluripotent capacity. Persistent microchimerism has the capacity for both beneficial and detrimental maternal health consequences. Both miscarriage and termination of pregnancy can result in fetal microchimerism. We sought to determine whether cellular fetal microchimerism is acquired during management of pregnancy loss and further explored factors that could influence fetal cell transfer, including viability of fetal tissue, surgical versus medical management and gestational age. METHODS Pregnant women (n= 150 samples from 75 women) with singleton pregnancies undergoing a TOP (n= 63) or treatment for embryonic or fetal demise (miscarriage, n= 12) were enrolled. Mononuclear cells were isolated from blood samples drawn before, and 30 min after, treatment. Fetal cellular microchimerism concentrations were determined using quantitative PCR for a Y chromosome-specific sequence, expressed as genome equivalents of fetal DNA per 100 000 maternal cell equivalents (gEq/10(5)). Detection rate ratios were determined according to clinical characteristics. RESULTS Cellular fetal microchimerism was found more often in post- compared with pretreatment samples, 24 versus 5% (P= 0.004) and at higher concentrations, 0-36 versus 0-0.7 gEq/10(5) (P< 0.001). Likelihood of microchimerism was higher in surgical than medical management, detection rate ratio 24.7 (P= 0.02). The detection rate ratio for TOP versus miscarriage was 16.7 for known male fetuses (P= 0.02). Microchimerism did not vary with gestational age. CONCLUSIONS Significant fetal cell transfer occurs during miscarriage and TOP. Exploratory analyses support relationships between obstetric clinical factors and acquisition of fetal cellular microchimerism; however, our limited sample size precludes definitive analysis of these relationships, and confirmation is needed. In addition, the long-term persistence and potential consequences of fetal microchimerism on maternal health merit further investigation.     

Sex chromosome trisomies in Europe: prevalence, prenatal detection and outcome of pregnancy

This study aims to assess prevalence and pregnancy outcome for sex chromosome trisomies (SCTs) diagnosed prenatally or in the first year of life. Data held by the European Surveillance of Congenital Anomalies (EUROCAT) database on SCT cases delivered 2000–2005 from 19 population-based registries in 11 European countries covering 2.5 million births were analysed. Cases included were livebirths diagnosed to 1 year of age, fetal deaths from 20 weeks gestation and terminations of pregnancy for fetal anomaly (TOPFA). In all, 465 cases of SCT were diagnosed between 2000 and 2005, a prevalence of 1.88 per 10,000 births (95% CI 1.71–2.06). Prevalence of XXX, XXY and XYY were 0.54 (95% CI 0.46–0.64), 1.04 (95% CI 0.92–1.17) and 0.30 (95% CI 0.24–0.38), respectively. In all, 415 (89%) were prenatally diagnosed and 151 (36%) of these resulted in TOPFA. There was wide country variation in prevalence (0.19–5.36 per 1000), proportion prenatally diagnosed (50–100%) and proportion of prenatally diagnosed resulting in TOPFA (13–67%). Prevalence of prenatally diagnosed cases was higher in countries with high prenatal detection rates of Down syndrome. The EUROCAT prevalence rate for SCTs diagnosed prenatally or up to 1 year of age represents 12% of the prevalence expected from cytogenetic studies of newborn babies, as the majority of cases are never diagnosed or are diagnosed later in life. There is a wide variation between European countries in prevalence, prenatal detection and TOPFA proportions, related to differences in screening policies as well as organizational and cultural factors.     

A Subset of Patients With Recurrent Spontaneous Abortion Is Deficient in Transforming Growth Factor β-2-Producing “Suppressor Cells” in Uterine Tissue Near the Placental Attachment Site

PROBLEM : To determine if patients with unexplained recurrent miscarriage have a deficiency of decidual immunosuppressor cells that produce transforming growth factor β type 2, as has been found in mice with abortion due to rejection and/or trophoblast failure. METHODS : Decidual biopsy specimens were taken as near to the placental attachment site as possible under ultrasound guidance from first trimester legal termination (control) patients with recurrent miscarriage and non-viable pregnancy, and from patients with sporadic missed abortion. The tissue was tested for TGFβ-2⁺ suppressor cells by in situ hybridization, immunohistochemistry, and analysis of supernatants. RESULTS : TGFβ-2-related suppressor molecules similar but not identical to those identified in pregnant mice were released by decidual lymphoid cells. Fifty percent of 14 recurrent miscarriage patients showed a lack of suppressor cells and 59% were subnormal in comparison to 20 controls and 5 sporadic miscarriage patients, where 80–85% of the patients had detectable suppressor cells. CONCLUSIONS : Suppressor cell deficiency is compatible with a role for rejection and/or trophoblast failure in some patients with recurrent miscarriage. Presence of suppressor cells in most patients with missed abortion (4/5) is compatible with an alternative cause of fetal death, similar to findings reported in genetic fetal death mice.     

Stability of the m.8993T->G mtDNA mutation load during human embryofetal development has implications for the feasibility of prenatal diagnosis in NARP syndrome

Background

Mitochondrial DNA (mtDNA) mutations cause a wide range of serious genetic diseases with maternal inheritance. Because of the high transmission risk and the absence of therapy in these disorders, at‐risk couples often ask for prenatal diagnosis (PND). However, because heteroplasmy load (coexistence of mutant and wild‐type mtDNA) may vary among tissues and with time, the possibility that a single fetal sample may not reflect the whole neonate impedes prenatal diagnosis of mtDNA diseases.

Methods

We performed 13 prenatal diagnoses for the NARP (neurogenic weakness, ataxia, retinitis pigmentosa) m.8993T→G mtDNA mutation (p.Leu156Arg) in the ATP synthase subunit 6 gene. Analyses were performed on chorionic villous (CVS) and/or amniocyte samples carried out at various stages of pregnancy, using a method enabling quantification of low DNA amounts.

Results

Maternal mutant loads ranged from 0 to 75% in blood and had no predictive value for the fetus status, except for women with no detectable mutant DNA, whose fetuses were consistently mutation‐free. In 8/13 PND, mutant load was <30%. These children are healthy at 2–7 years of age. In 5/13 PND, mutant load ranged from 65 to 100%, and parents preferred to terminate the pregnancies (15–22 weeks of gestation). Single‐cell analysis of 20 trophoblastic cells and 21 amniocytes isolated from two affected fetuses found an average mutant load close to the overall CVS and amniocyte mutant load, despite striking intercellular variation. The m.8993T→G mutant loads, assessed in 7, 17, 11, and 5 different tissues from 4 terminations, respectively, were identical in all tissues from a given individual (mean (SD) 78 (1.2)%, 91 (0.7)%, 74 (2)%, and 63 (1.6)% for the 4 fetuses, respectively).

Conclusions

Our results indicate that the placental/amniotic mutant loads do reflect the NARP mutant mtDNA load in the whole fetus, even when the sample amount is small, and suggest that heteroplasmy level remains stable during pregnancy, at least after 10 weeks of gestation. Although these data establish the feasibility of PND for this mutation, assessing more precisely the correlation between mutant load and disease severity should further help in interpreting PND results.     

Specific association of a CLEC16A/KIAA0350 polymorphism with NOD2/CARD15? Crohn's disease patients

Independent genome-wide association studies highlighted the function of CLEC16A/KIAA0350 polymorphisms modifying the risk to either multiple sclerosis (rs6498169) or type 1 diabetes (rs2903692). This C-type lectin gene maps to a linkage disequilibrium block at 16p13 and a functional role of this gene could be envisaged for other immune-related conditions, such as inflammatory bowel disease (IBD). The present study, aimed at investigating the association of those two polymorphisms with IBD, included 720 IBD patients and 550 ethnically matched healthy controls. The effect of rs2903692 previously described in diabetes was observed specifically for Crohn''s disease (CD) patients lacking the main susceptibility factor described to date, that is, three polymorphisms within another pattern recognition gene, NOD2/CARD15 (NOD2⁻ vs NOD2⁺ CD patients, G vs A: P=0.008; OR (95% CI)=1.54 (1.10–2.15); NOD2⁻ CD patients vs controls: P=0.008; OR (95% CI)=1.37 (1.08–1.73)). Replication of these findings was performed in independent Spanish cohorts of 544 IBD patients and 340 controls and the combined data yielded significant differences (405 NOD2⁻ vs 204 NOD2⁺ CD patients, G vs A: P=0.0012; OR_M-H (95% CI)=1.49 (1.17–1.90); NOD2⁻ CD patients vs controls: P=0.0007; OR_M-H (95% CI)=1.35 (1.13–1.60)). The pooled analysis of the ulcerative colitis patients vs controls also yielded a significant risk (P=0.0005; OR (95% CI)=1.52 (1.19–1.93)). These data would suggest that microbial recognition through different pathways seems to converge in the development of these polygenic bowel diseases.     

Feto-maternal microchimerism in connective tissue diseases

Fetal progenitor cells traffic to the mother during pregnancy and can persist in the maternal circulation for many years. Feto-maternal microchimerism has been reported in women with scleroderma, but its contribution to the disease pathogenesis remains unclear. Furthermore, the involvement of microchimerism in other connective tissue diseases is controversial. We studied 243 females, 122 of whom had previously carried a male fetus (50 healthy controls, 23 patients with scleroderma, and 49 with other connective tissue diseases). The presence of the male-specific SRY sequence was analyzed using a kinetic quantitative ELISA PCR assay that allows detection of one to three male cells in one million female cells. The percentage of SRY-positive samples was not different among women having borne son(s): 16% (95% confidence interval 0.07-0.29) in healthy controls, 21.7% (0.07-0.44) in patients with scleroderma and 25.5% (0.14-0.40) in patients with connective tissue diseases (p=0.25). The mean number of fetal cells was similar in the three groups. Among the 121 females who never carried a male fetus, no healthy woman was SRY positive. However, 33% of patients with scleroderma and 22.9% of women with connective tissue diseases were chimeric, a phenomenon which might be related to early miscarriage(s). Therefore, feto-maternal microchimerism is a common event in both healthy controls and patients with connective tissue diseases, and is unlikely to represent per se a risk factor for these diseases.     

Methionine synthase A2756G polymorphism and cancer risk: a meta-analysis

Polymorphisms in methionine synthase (MTR) gene may be involved in carcinogenesis by affecting DNA methylation. However, association studies on MTR A2756G polymorphism in cancers have reported conflicting results. Therefore we performed a meta-analysis to better assess the associations. A total of 24 896 cancer patients and 33 862 controls from 52 articles for MTR A2756G were investigated. Overall, individuals carrying MTR 2756GG genotype had a subtly reduced cancer risk under a recessive genetic model (odds ratio (OR), 0.92; P=0.053; 95% confidence interval (95% CI), 0.84–1.00; I²=0.0% P_{heterogeneity}=0.61). In the subgroup analyses by ethnicity, 2756GG was associated with a significantly reduced cancer risk in European populations (OR, 0.83; P=0.001; 95% CI, 0.74–0.93; I²=0.0% P_{heterogeneity}=0.99). However, in Asian populations, a significantly elevated association between 2756GG genotype and cancer risk was observed (OR, 1.33; P=0.012; 95% CI, 1.06–1.65; I²=0.0% P_{heterogeneity}=0.50). In studies stratified by tumor site, there was a significantly reduced risk of acute lymphoblastic leukemia (ALL) (OR, 0.54; P=0.049; 95% CI, 0.29–1.00; I²=10.7% P_{heterogeneity}=0.33) and colorectal cancer (OR, 0.63; P=0.004; 95% CI, 0.47–0.87; I²=0.0% P_{heterogeneity}=0.73) in European populations. Our study indicates that MTR A2756G polymorphism is a candidate gene polymorphism for cancer susceptibility regardless of environmental factors. Large-scale, well-designed, and population-based studies are required to further investigate gene–gene and gene–environment interactions on MTR A2756G polymorphism and tissue-specific cancer risk in an ethnicity-specific population.     

Circulating levels of inhibin A,activin A and follistatin in missed and recurrent miscarriages

BACKGROUND: The aim of this study was to investigate the changes in circulating levels and the clinical use of inhibin A, activin A and follistatin as endocrine markers of early pregnancy loss. METHODS: Blood samples were collected from women presenting with a sporadic missed miscarriage (n = 10), and controls having pregnancy termination at 8-12 weeks (n = 15) and from women with a history of unexplained recurrent miscarriages (n = 12) at 6-12 weeks gestation. All samples were assayed for inhibin A, inhibin B, activin A, follistatin, hCG, estradiol and progesterone. RESULTS: Serum inhibin A, hCG, estradiol and progesterone levels were significantly ( approximately 2-3 fold) decreased in sporadic miscarriages compared with controls. In the recurrent miscarriage group, time dependent changes in plasma inhibin A and hCG levels were significantly (P < 0.05) altered in the group that had a subsequent miscarriage compared with those who had a live birth. At 6-7 weeks gestation, plasma inhibin A ( approximately 4 fold, P < 0.01), hCG ( approximately 4 fold, P < 0.01) and estradiol ( approximately 2 fold, P < 0.001) levels were significantly lower in women who went on to have another miscarriage than those with a live birth. Inhibin B levels were near the detection limit of the assay. CONCLUSIONS: Our findings suggest that inhibin A is a specific marker of early pregnancy loss before the onset of the clinical symptoms of recurrent miscarriage. There is a high degree of association between levels of inhibin A and hCG in cases of miscarriage, indicating that these two proteins could be used in combination to predict future pregnancy outcome.     

The FAS ligand promoter polymorphism,rs763110 (?844C>T), contributes to cancer susceptibility: evidence from 19 case–control studies

The potentially functional polymorphism, rs763110 (−844C>T), in the promoter region of the FAS ligand (FASL) gene, has been implicated in cancer risk, but individually published studies show inconclusive results. To derive a more precise estimation of the association between the FASL rs763110 and risk of cancer, we performed a meta-analysis of 19 published studies that included 11 105 cancer cases and 11 372 controls. We used odds ratios (ORs) and 95% confidence intervals (CIs) to assess the strength of the associations. Overall, the rs763110 CT and TT variant genotypes were associated with a significantly reduced cancer risk of all cancer types in different genetic models (homozygote comparison: OR=0.80, 95% CI: 0.68–0.95, P_{heterogeneity}=0.001; heterozygote comparison: OR=0.82, 95% CI: 0.72–0.95, P_{heterogeneity}<0.001; dominant model comparison: OR=0.82, 95% CI: 0.71–0.94, P_{heterogeneity}<0.001; and recessive model comparison: OR=0.88, 95% CI: 0.81–0.96, P_{heterogeneity}=0.074). In the stratified analyses, the risk remained for studies of the smoking-related cancers and Asian populations, or population-based studies in all the genetic models. Although some modest bias could not be eliminated, this meta-analysis suggests that the FASL rs763110 T allele has a possible protective effect on cancer risk.     

Perinatal Listeria monocytogenes susceptibility despite preconceptual priming and maintenance of pathogen-specific CD8^＋ T cells during pregnancy

Listeria monocytogenes （Lm） is an intracellular bacterium with unique predisposition for systemic maternal infection during pregnancy and morbid consequences for the developing fetus. Given the high mortality associated with prenatal Lm infection, strategies for augmenting protective immunity during the exceedingly vulnerable period of pregnancy are urgently needed. Herein, protection conferred by attenuated Lm administered before pregnancy against subsequent virulent Lm prenatal infection was evaluated. We show that protection against secondary Lm infection in non-pregnant mice is sharply moderated during allogeneic pregnancy because significantly more bacteria are recovered from maternal tissues, despite the numerical and functional preservation of pathogen-specific CD8^＋ T cells. More importantly, preconceptual priming does not protect against in utero invasion or fetal wastage because mice inoculated with attenuated Lm prior to pregnancy and naive pregnant controls each showed near complete fetal resorption and pathogen recovery from individual concepti after Lm infection during pregnancy. Remarkably, the lack of protection against prenatal Lm infection with preconceptual priming in allogeneic pregnancy is restored during syngeneic pregnancy. Thus, maternal-fetal antigen discordance dictates the ineffectiveness of preconceptual vaccination against fetal complications after prenatal Lm infection, despite the numerical and functional preservation of pathogen-snecific CD8^＋ T cells.     

Incidence of Toxoplasma gondii Infection in 35,940 Pregnant Women in Norway and Pregnancy Outcome for Infected Women

From 1992 to 1994 a screening program for detection of specific Toxoplasma gondii antibodies involving 35,940 pregnant women was conducted in Norway. For women with serological evidence of primary T. gondii infection, amniocentesis and antiparasitic treatment were offered. The amniotic fluid was examined for T. gondii by PCR and mouse inoculation to detect fetal infection. Infants of infected mothers had clinical and serological follow-up for at least 1 year to detect congenital infection. Of the women 10.9% were infected before the onset of pregnancy. Forty-seven women (0.17% among previously noninfected women) showed evidence of primary infection during pregnancy. The highest incidence was detected (i) among foreign women (0.60%), (ii) in the capital city of Oslo (0.46%), and (iii) in the first trimester (0.29%). Congenital infection was detected in 11 infants, giving a transmission rate of 23% overall, 13% in the first trimester, 29% in the second, and 50% in the third. During the 1-year follow-up period only one infant, born to an untreated mother, was found to be clinically affected (unilateral chorioretinitis and loss of vision). At the beginning of pregnancy 0.6% of the previously uninfected women were falsely identified as positive by the Platelia Toxo-IgM test, the percentage increasing to 1.3% at the end of pregnancy. Of the women infected prior to pregnancy 6.8% had persisting specific immunoglobulin M (IgM). A positive specific-IgM result had a low predictive value for identifying primary T. gondii infection.     

Association of the TGF-�� receptor genes with abdominal aortic aneurysm

Abdominal aortic aneurysm (AAA) is a multifactorial condition. The transforming growth factor β (TGF-β) pathway regulates vascular remodeling and mutations in its receptor genes, TGFBR1 and TGFBR2, cause syndromes with thoracic aortic aneurysm (TAA). The TGF-β pathway may be involved in aneurysm development in general. We performed an association study by analyzing all the common genetic variants in TGFBR1 and TGFBR2 using tag single nucleotide polymorphisms (SNPs) in a Dutch AAA case–control population in a two-stage genotyping approach. In stage 1, analyzing 376 cases and 648 controls, three of the four TGFBR1 SNPs and nine of the 28 TGFBR2 SNPs had a P<0.07. Genotyping of these SNPs in an independent cohort of 360 cases and 376 controls in stage 2 confirmed association (P<0.05) for the same allele of one SNP in TGFBR1 and two SNPs in TGFBR2. Joint analysis of the 736 cases and 1024 controls showed statistically significant associations of these SNPs, which sustained after proper correction for multiple testing (TGFBR1 rs1626340 OR 1.32 95% CI 1.11–1.56 P=0.001 and TGFBR2 rs1036095 OR 1.32 95% CI 1.12–1.54 P=0.001 and rs4522809 OR 1.28 95% CI 1.12–1.46 P=0.0004). We conclude that genetic variations in TGFBR1 and TGFBR2 associate with AAA in the Dutch population. This suggests that AAA may develop partly by similar defects as TAA, which in the future may provide novel therapeutic options.     

Fetal polymorphisms at the ABCB1-transporter gene locus are associated with susceptibility to non-syndromic oral cleft malformations

ATP-binding cassette (ABC) proteins in the placenta regulate fetal exposure to xenobiotics. We hypothesized that functional polymorphisms in ABC genes influence risk for non-syndromic oral clefts (NSOC). Both family-based and case–control studies were undertaken to evaluate the association of nine potentially functional single-nucleotide polymorphisms within four ABC genes with risk of NSOC. Peripheral blood DNA from a total of 150 NSOC case-parent trios from Singapore and Taiwan were genotyped, as was cord blood DNA from 189 normal Chinese neonates used as controls. In trios, significant association was observed between the ABCB1 single-nucleotide polymorphisms and NSOC (P<0.05). Only ABCB1 rs1128503 retained significant association after Bonferroni correction (odds ratio (OR)=2.04; 95% confidence interval (CI)=1.42–2.98), while rs2032582 and rs1045642 showed nominal significance. Association with rs1128503 was replicated in a case–control analysis comparing NSOC probands with controls (OR=1.58; 95% CI=1.12–2.23). A comparison between the mothers of probands and controls showed no evidence of association, suggesting NSOC risk is determined by fetal and not maternal ABCB1 genotype. The two studies produced a combined OR of 1.79 (95% CI=1.38–2.30). The T-allele at rs1128503 was associated with higher risk. This study thus provides evidence that potentially functional polymorphisms in fetal ABCB1 modulate risk for NSOC, presumably through suboptimal exclusion of xenobiotics at the fetal–maternal interface.     

A single nucleotide polymorphism in APOA5 determines triglyceride levels in Hong Kong and Guangzhou Chinese

Single nucleotide polymorphisms (SNPs) in the apolipoprotein A5 (APOA5) gene have been associated with hypertriglyceridaemia. We investigated which SNPs in the APOA5 gene were associated with triglyceride levels in two independent Chinese populations. In all, 1375 subjects in the Hong Kong Cardiovascular Risk Factor Prevalence Study were genotyped for five tagging SNPs chosen from HapMap. Replication was sought in 1996 subjects from the Guangzhou Biobank Cohort Study. Among the five SNPs, rs662799 (-1131T>C) was strongly related to log-transformed triglyceride levels among Hong Kong subjects (β=0.192, P=2.6 × 10⁻¹³). Plasma triglyceride level was 36.1% higher in CC compared to TT genotype. This association was confirmed in Guangzhou subjects (β=0.159, P=1.3 × 10⁻¹²), and was significantly irrespective of sex, age group, obesity, metabolic syndrome, hypertension, diabetes, smoking and alcohol drinking. The odds ratios and 95% confidence interval for plasma triglycerides ≥1.7 mmol/l associated with TC and CC genotypes were, respectively, 1.81 (1.37–2.39) and 2.22 (1.44–3.43) in Hong Kong and 1.27 (1.05–1.54) and 1.97 (1.42–2.73) in Guangzhou. Haplotype analysis suggested the association was due to rs662799 only. The corroborative findings in two independent populations indicate that the APOA5-1131T>C polymorphism is an important and clinically relevant determinant of plasma triglyceride levels in the Chinese population.     

Endometrial protein PP14 and CA-125 in recurrent miscarriage patients; correlation with pregnancy outcome

The concentrations of endometrial proteins PP14 and CA-125 were measured in uterine flushings taken on days LH+10 and LH+12 (10 and 12 days after luteinizing hormone surge) of the menstrual cycle from 15 normal, fertile women and 49 women who suffered recurrent miscarriage. The concentration of PP14 was significantly lower in the flushings from the recurrent miscarriage patients than in those from fertile controls on both day LH+10 (median: 1300, range: 3-10 300 ng/ml versus median: 13 933, range: 2174-40 404 ng/ml; P < 0.01) and LH+12 (median: 1560, range: 820-12 100 ng/ml versus median: 14 047, range 1402-62 108 ng/ml; P < 0.05). Similarly concentrations of CA-125 were significantly lower in flushings from recurrent miscarriage women compared to controls on both day LH + 10 (median: 1555, range: 47-6710 U/ml versus median: 6385.5, range 2884-27 731 U/ml, P < 0.01) and LH+12 (median: 2892, range: 956-9974 U/ml versus median: 7127.5, range: 1591-21 343 U/ml; P < 0.05). In contrast there was no significant difference in the concentration of PP14 in plasma samples taken on the same days as the flushings from recurrent miscarriage patients and fertile controls. The concentrations of PP14 in uterine flushings obtained on day LH + 10 or LH + 12 from recurrent miscarriage women during a pre-pregnancy investigative cycle were significantly lower (P < 0.05) in patients who went on to miscarry (median: 1000, range: 9-2900 ng/ml) than those who went on to have a live birth (median: 1440, range: 4-12 100 ng/ml) during a subsequent pregnancy. In contrast there was no significant difference in uterine CA-125 or plasma PP14 concentrations between these two groups of recurrent miscarriage patients. The results suggest that measurements of uterine PP14 and CA-125 may be useful in the assessment of endometrial development in recurrent miscarriage patients and suggest the importance of PP14 in preparing the endometrium for embryo implantation. In addition pre-pregnancy uterine PP14 measurements may be useful in predicting subsequent pregnancy outcome.      

Multiple thrombophilic gene mutations rather than specific gene mutations are risk factors for recurrent miscarriage

PROBLEM: Recurrent miscarriage is a heterogeneous condition. While the role of acquired thrombophilia has been accepted as an etiology of recurrent miscarriage, the contribution of specific inherited thrombophilic genes to this disorder has remained controversial. We compared the prevalence of 10 thrombophilic gene mutations among women with a history of recurrent miscarriages and fertile control women. METHOD OF STUDY: A total of 150 women with a history of two or more recurrent pregnancy losses and 20 fertile control women with no history of pregnancy losses had buccal swabs taken for DNA analyses of 10 gene mutations [factor V G1691A, factor V H1299R (R2), factor V Y1702C, factor II prothrombin G20210A, factor XIII V34L, beta-fibrinogen -455G>A, PAI-1 4G/5G, HPA1 a/b (L33P), MTHFR C677T, MTHFR A1298C]. The prevalence of these mutations was compared between women experiencing recurrent miscarriage and controls. RESULTS: No differences in the frequency of specific gene mutations were detected when women with recurrent miscarriage were compared with control women. However, the prevalence of homozygous mutations and total gene mutations among patients with recurrent miscarriage was significantly higher than among controls. Homozygous mutations were found in 59% of women with a history of recurrent pregnancy loss contrasted to 10% of control women. More than three gene mutations among the 10 genes studied were observed in 68% of women with recurrent miscarriage and 21% of controls. CONCLUSION: Inherited thrombophilias are associated with recurrent miscarriage. This association is manifest by total number of mutations rather than specific genes involved.     

Skewed X chromosome inactivation and early-onset breast cancer

Background

Skewed X chromosome inactivation may be more common in women with epithelial ovarian cancer and early‐onset breast cancer. We tested this hypothesis in a group of 235 breast cancer patients and 253 controls (mean age 45.8 years) from a larger population based case control study.

Methods

We measured X chromosome inactivation with the AR gene assay in lymphocyte DNA digested with the methylation specific enzyme HpaII. We judged skewness using an adjusted measure (relative to the undigested sample) with a cut point of 75%, and an unadjusted measure where skewed was defined as >90% of the signal from one allele in the HpaII digested sample.

Results

There were no significant differences in any of the skewing measures between cases and controls. Using the adjusted skewing measure among pre‐menopausal subjects under the age of 50, 14% of cases versus 11% of controls were skewed, OR = 1.2, 95% CI 0.6 to 2.3; using the unadjusted measure, OR = 0.9, 95% CI 0.4 to 2.0.

Conclusions

While we cannot rule out a subtle difference of approximately twofold or less, we have failed to find a significant difference in the prevalence of skewed X chromosome inactivation in younger women with breast cancer compared to controls.     

An urgent need for a change in policy revealed by a study on prenatal testing for Duchenne muscular dystrophy

Prenatal diagnosis for Duchenne muscular dystrophy (DMD) was introduced in the Netherlands in 1984. We have investigated the impact of 26 years (1984–2009) of prenatal testing. Of the 635 prenatal diagnoses, 51% were males; nearly half (46%) of these were affected or had an increased risk of DMD. As a result 145 male fetuses were aborted and 174 unaffected boys were born. The vast majority (78%) of females, now 16 years or older, who were identified prenatally have not been tested for carrier status. Their average risk of being a carrier is 28%. We compared the incidences of DMD in the periods 1961–1974 and 1993–2002. The incidence of DMD did not decline but the percentage of first affected boys increased from 62 to 88%. We conclude that a high proportion of families with de novo mutations in the DMD gene cannot make use of prenatal diagnosis, partly because the older affected boys are not diagnosed before the age of five. Current policy, widely accepted in the genetic community, dictates that female fetuses are not tested for carrier status. These females remain untested as adults and risk having affected offspring as well as progressive cardiac disease. We see an urgent need for a change in policy to improve the chances of prevention of DMD. The first step would be to introduce neonatal screening of males. The next is to test females for carrier status if requested, prenatally if fetal DNA is available or postnatally even before adulthood.     

A longitudinal study of pregnancy outcome following idiopathic recurrent miscarriage.

Recurrent miscarriage is a difficult clinical problem occurring in approximately 1-2% of fertile women. Following investigation, most cases fail to reveal an identifiable cause and are therefore classified as idiopathic. The aim of this study was to identify important gestational milestones for pregnancy success prediction in women following idiopathic recurrent miscarriage. A total of 325 consecutive patients with idiopathic recurrent miscarriage was involved in a prospective longitudinal observational study. Patients were identified from a miscarriage database of 716 patients. Preconceptual presentation and investigation excluded patients from the study sample with known associations of recurrent pregnancy loss, such as antiphosholipid syndrome, oligomenorrhoea, mid-trimester loss and other rare causes, e.g. abnormal parental karyotype. Following early presentation in a subsequent pregnancy, all patients followed a standard clinic protocol including fetal viability ultrasonography on a fortnightly basis throughout the first trimester. Kaplan-Meier curves were constructed for pregnancy outcome. Out of 325 idiopathic cases, 70% (n = 226) conceived, with a 75% success rate. Of 55 miscarriages, longitudinal assessment showed that six losses occurred following detection of fetal cardiac activity (3%). Data from this large study group have enabled accurate prediction of future pregnancy success and have established important gestational milestones for women with idiopathic recurrent miscarriage.     

Two British women studies replicated the association between the Val66Met polymorphism in the brain-derived neurotrophic factor (BDNF) and BMI

The goal of this study is to investigate the relationship between the Val66Met polymorphism in the brain-derived neurotrophic factor (BDNF) and body mass index (BMI) in two sizable and well-characterized populations of British women: the British Women''s Heart and Health Study (BWHHS) (age 60–79 years) and the mothers from the Avon Longitudinal Study of Parents and Children (age 16–44 years). We genotyped the Val66Met polymorphism (rs6265) in these two populations, and conducted a linear regression analysis to test for an association between this polymorphism and BMI. Both study populations indicated an association between BMI and the Val66Met polymorphism, with individuals carrying the Met–Met genotype having a lower mean BMI than those with the Val–Met or Val–Val genotypes (in the BWHHS): mean BMI difference=−0.911 kg/m², 95% confidence interval (CI): −1.70 to −0.12, P=0.023; in the mothers from the Avon Longitudinal Study of Parents and Children (ALSPAC): mean BMI difference=−0.57 kg/m², 95%CI: −1.08 to −0.054, P=0.03). In a pooled analysis of these two studies, together with one further published study that provided data in a suitable format for inclusion in our meta-analysis, we found a pooled difference of −0.76 (95% CI: −1.16, −0.036) for adult women; I²–test for heterogeneity=51%, P=0.13. Our study indicated an association between BDNF and BMI in two general population studies of women. The exact role of BDNF in weight regulation merits further investigation.