Haplotype-based association of ACE I/D, AT1R 1166A>C, and AGT M235T polymorphisms in renin-angiotensin-aldosterone system genes in Korean women with idiopathic recurrent spontaneous abortions

miR604A>G gene polymorphism is associated with recurrent pregnancy loss in Turkish women

OBJECTIVE

Recurrent pregnancy loss is considerably a reproductive health problem for couples. Genetic, epigenetic, and environmental factors play an important role in the development of recurrent pregnancy loss. While there are many causes, genetic and epigenetic factors are common. In this study, we aimed to examine the association between miR604 (rs2368393) A>G gene polymorphism and the risk of recurrent miscarriage in the Turkish population.

METHODS

The study included 250 participants (i.e., 150 patients and 100 controls). DNA samples were isolated from peripheral blood, and polymerase chain reactions and restriction fragment length polymorphism methodologies were applied.

RESULTS

The genotype distribution and allele frequencies of miR604A>G gene showed statistically significant differences between patients and control groups (p=0.002 and p<0.002, respectively).

CONCLUSION

As a result of the study, we found that the AA genotype and A allele of the miR604A>G gene were statistically significant for the risk of recurrent pregnancy loss in Turkish women.

Thrombophilic gene polymorphisms and recurrent pregnancy loss: a systematic review and meta-analysis

PURPOSE

Recurrent pregnancy loss (RPL) is affecting 1-4% of women who conceive approximately, and no cause could be found in more than 50% of women suffering from RPL. Inherited thrombophilias have got increasing attention in women with unexplained RPL, so we aim to explore the relationship among these most common thrombophilic polymorphisms and RPL through a literature review and meta-analysis.

METHODS

Observational studies from PubMed, Embase, Cochrane, and Web of Science from 1997 to 7 April 2022 were searched. For each genetic variant, a fixed or random-effect model was used according to the heterogeneity test to calculate pooled ORs and 95% CIs for both dominant and recessive genetic models. Egger's line regression test was used to assess publication bias. The quality of the included articles was assessed by the Newcastle Ottawa scale.

RESULTS

A total of 124 articles comprising 17,278 RPL patients and 16,021 controls were included. Results showed that hyperhomocysteinemia (MTHFR) C677T (dominant model: OR, 1.43; 95% CI, 1.25-1.64; recessive model: OR, 1.60; 95% CI, 1.36-1.87), MTHFR A1298C (dominant model: OR, 1.66; 95% CI, 1.26-2.18; recessive model: OR, 1.79; 95% CI, 1.42-2.26), PAI-1 4G/5G (dominant model: OR, 1.67; 95% CI, 1.36-2.06; recessive model: OR, 1.80; 95% CI, 1.39-2.32), angiotensin-converting enzyme I/D (OR, 1.23; 95% CI, 1.00-1.53), Factor XIII V34L (OR, 1.38; 95% CI, 1.02-1.87), and β-fibrinogen-455G/A (OR, 1.60; 95% CI, 1.02-2.51) were significantly associated with RPL.

CONCLUSION

This study provides potentially useful clinical markers to evaluate the risk of RPL or to help unexplained RPL patients identify possible causes, which may allow for targeted treatment.

Angiotensin-Converting Enzyme (ACE) Insertion/Deletion (I/D) Polymorphism as a Conjoint Regulator of Coagulation, Fibrinolytic, and RAAS Pathway in Infertility and Associated Pregnancy Complications

Despite the increase in assisted reproductive technologies, the high rates of infertility and pregnancy complications are a major concern to infertility specialists worldwide. Infertility may be attributed to pregnancy complications like thrombophilia, preeclampsia and fibrin-induced recurrent pregnancy loss (RPL). Renin-angiotensin-aldosterone system (RAAS) directly or indirectly causes preeclampsia and thrombophilia through the fibrinolytic pathway that ultimately leads to RPL or infertility. The underlying mechanisms of this interaction are still unclear. The present comprehensive review is intended to demonstrate the role and interaction of RAAS and fibrinolytic pathways in pregnancy complications. How this interaction can induce pregnancy complications, and ultimately infertility, is also discussed in the light of current evidence. This study also presents common markers that link RAAS and fibrinolytic processes in developing thrombophilia, preeclampsia and RPL. The common link in these pathways is ACE gene I/D polymorphism. Apart from ACE, PAI-1, VIIa, XIIa, AT1R, AT1AA, and TF are common molecules that can delineate the underlying causes of pregnancy complications and infertility.

Role of polymorphisms on the Recurrent Pregnancy Loss: A systematic review, Meta-analysis and bioinformatic analysis

Recurrent miscarriage (RM) is a major reproductive health issue. RM is a multi-factorial disease, and is affected by environmental, genetic, and epigenetic factors. Genetics has a common role in recurrent miscarriage occurrence. It seems that molecular genetics has a great role in RSA incidence. So, in these years, RM has become for a major subject of genetics research. There are many genes that are involved in each phase for successful reproduction. This research aimed to evaluate the effect of all studied polymorphisms in studies on RSA that have not been included in any meta-analysis. PubMed, Scopus, and Web of Science databases were recruited to investigate the related articles. The systematic review results identified 143 studies worldwide. Thirteen genes have been included in assessing the case-control studies. Sixty-four SNPs were recruited to assess the association between genetic factors and RSA susceptibility. Ninety-two studies containing twenty two SNPs (from 10 genes) were included in the quantitative analysis. Bioinformatic analysis indicated that rs12722482 showed "Damaging Status" by double servers, and rs315952 and rs854560 had "Possibly damaging" status in the PolyPhen-2 server. MethPrimer server indicated that there is "CpG Island" in the rs10895068, rs1130355, and rs41557518 variants, and rs10895068-G allele makes a CpG dinucleotide which can change the gene methylation and result in altering the gene expression. So, further studies on rs12722482 and rs10895068 can demonstrate valuable results. To the best of our knowledge, this systematic review has covered the all studied polymorphisms of HLA-C, HLA-G, PON1, AGTR1, TAFI, FAS, FAS-L, ESR1, PGR, CTLA-4, MMP-2, MMP-3, MMP-9, and IL1RN for the first time. Also, we did a novel meta-analysis for AGTR1 rs5186, TAFI rs1926447, rs3742264, HLA-G rs1063320, rs1233334, rs1736936, rs2249863, PON1 rs662, rs854560, FAS rs2234767, rs1800682, FAS-L rs763110, ESR1, rs9340799, rs3798759, PGR rs1042838, CTLA4 rs4553808, rs5742909, rs231775, rs3087243, and MMP-2 rs243865 and updated statistical finding for rs2234693 and rs371194629. Rs2234693, rs9340799, rs231775, and rs371194629 demonstrated a significant association with RSA risk. Some variations showed significant association, while further studies are suggested to confirm the results. Finally, Rs4553808 and rs5742909 revealed no significant deviation in the results. It is suggested that these SNPs may be excluded from subsequent case-control studies or other analyses.

The Angiotensin-converting Enzyme Insertion/Deletion Polymorphism as a Common Risk Factor for Major Pregnancy Complications

Idiopathic pregnancy complications pose a major threat to both maternal and fetal health worldwide. Numerous studies have implicated the role of the renin-angiotensin system (RAS) in the development of obstetric syndromes, since it is crucial for the uteroplacental function. A major RAS component is the angiotensin-converting enzyme (ACE), which hydrolyses angiotensin I to angiotensin II, and not only regulates arterial pressure, but also fibrinolytic activity, indirectly, through the expression of plasminogen activator inhibitor-1. A key functional polymorphism of the ACE gene is the insertion/deletion (I/D) polymorphism, which affects gene expression and product levels, and can therefore lead to high blood pressure and/or reduced fibrinolytic activity. These can cause major pregnancy complications, such as preeclampsia, recurrent pregnancy loss and preterm birth. This review discusses how the ACE I/D is associated with susceptibility towards pregnancy complications, on its own or in combination with other functional gene polymorphisms such, as the angiotensin II receptor type 1 (AT1R) A1166CC, angiotensin II receptor type 2 (AT2R) G1332A, plasminogen activator inhibitor-1 (PAI-1) 4G/5G, matrix metallopeptidase-9 (MMP-9) C1562T, angiotensinogen (AGT) M235T, renin (REN) 83A/G, factor XIII (F13) Val34Leu and endothelial nitric oxide synthase (eNOS) 4a/b.

Genetic Polymorphisms in miR-604A>G, miR-938G>A, miR-1302-3C>T and the Risk of Idiopathic Recurrent Pregnancy Loss

The purpose of this study was to investigate whether polymorphisms in five microRNAs (miRNAs), miR-604A>G, miR-608C>G, 631I/D, miR-938G>A, and miR-1302-3C>T, are associated with the risk of idiopathic recurrent pregnancy loss (RPL). Blood samples were collected from 388 patients with idiopathic RPL (at least two consecutive spontaneous abortions) and 227 control participants. We found the miR-604 AG and AG + GG genotypes of miR-604, the miR-938 GA and GA + AA genotypes of miR-938, and the miR-1302-3CT and CT + TT genotypes of miR-1302-3 are less frequent than the wild-type (WT) genotypes, miR-604AA, miR-938GG, and miR-1302-3CC, respectively, in RPL patients. Using allele-combination multifactor dimensionality reduction (MDR) analysis, we found that eight haplotypes conferred by the miR-604/miR-608/miR-631/miR-938/miR-1302-3 allele combination, A-C-I-G-T, A-C-I-A-C, G-C-I-G-C, G-C-I-G-T, G-G-I-G-C, G-G-I-G-T, G-G-I-A-C, G-G-D-G-C, three from the miR-604/miR-631/miR-938/miR-1302-3 allele combination, A-I-G-T, G-I-G-C, G-I-A-T, one from the miR-604/miR-631/miR-1302-3 allele combination, G-I-C, and two from the miR-604/miR-1302-3 allele combination, G-C and G-T, were less frequent in RPL patients, suggesting protective effects (all p < 0.05). We also identified the miR-604A>G and miR-938G>A polymorphisms within the seed sequence of the mature miRNAs and aligned the seed sequences with the 3′UTR of putative target genes, methylenetetrahydrofolate reductase (MTHFR) and gonadotropin-releasing hormone receptor (GnRHR), respectively. We further found that the binding affinities between miR-604/miR-938 and the 3′UTR of their respective target genes (MTHFR, GnRHR) were significantly different for the common (miR-604A, miR-938G) and variant alleles (miR-604G, miR-938A). These results reveal a significant association between the miR-604A>G and miR-938G>A polymorphisms and idiopathic RPL and suggest that miRNAs can affect RPL in Korean women.

Frequency of the rs 14035 polymorphism of RAN gen in recurrent pregnancy loss: A case-control study

Background

Genetic factors could account for recurrent pregnancy loss (RPL). The RAN gene is a member of the "large RAS family" and a small GTPase that is essential for the translocation of Ribonucleic acid (RNA) and proteins through the nuclear pore. Mutation in the RAN constitutive gene could stop DNA synthesis and alter the expression of genes in the uterus, likely playing a role in recurrent miscarriage.

Objective

The aim was to investigate the frequency of RAN (rs 14035) polymorphism in women with RPL compared with women without abortion history.

Materials and Methods

In this case-control study, 100 women with at least two consecutive miscarriages before the 20th wk of gestation and having spouses with karyotype and normal sperm parameters as the case group and 100 women with no history of abortion and having at least one successful pregnancy and normal delivery as the control group. The groups were age matched (20-40 yr). The rs 14035 polymorphism of RAN gene was investigated by Polymerase Chain Reaction-Restriction Fragment Length poly morphism technique and the frequency of which was compared between the two groups.

Results

The frequency of TT, TC, and CC genotypes of RAN gene polymorphism in the case group were 9%, 40%, and 51%, respectively, and in the control group were 11%, 38%, and 51%, respectively. There was no significant difference in the genotypes between two groups (p = 0.882).

Conclusion

According to our results, it seems that RAN polymorphism (rs 14035) is not associated with the risk of RPL in this study population.

Genetic Association of Angiotensin-Converting Enzyme (ACE) Gene I/D Polymorphism with Preterm Birth in Korean Women: Case-Control Study and Meta-Analysis

BACKGROUND AND OBJECTIVES

The ACE gene encodes the angiotensin-converting enzyme (ACE), a component of the renin-angiotensin system. Increased ACE activity may cause abnormal regulation of placental circulation and angiogenesis, resulting in adverse pregnancy outcomes. Previous studies have reported that the insertion/deletion (I/D) polymorphism of the ACE gene is associated with the development of preterm birth (PTB). However, results of the association between ACE gene I/D and PTB are inconsistent in various populations. Therefore, we performed a case-control study and a meta-analysis to evaluate the association between ACE I/D polymorphism and PTB. Materials and Methods: We analyzed a total of 254 subjects (111 patients with PTB and 143 women at ≥38 weeks gestation) for the case-control study. For the meta-analysis, we searched Google Scholar, PubMed, and NCBI databases with the terms "ACE," "angiotensin-converting enzyme," "preterm birth," "preterm delivery," and their combinations. Results: Our results of the case-control study indicated that ACE I/D polymorphism is significantly associated with PTBs in the overdominant genetic model (odds ratio (OR) 0.57, 95% confidence interval (CI) 0.347-0.949, p = 0.029) and that the ID genotype of ACE I/D polymorphism has a protective effect for PTB (OR 0.57, 95% CI 0.333-0.986, p = 0.043). Similarly, the meta-analysis showed that the OR for the ACE gene ID genotype was 0.66 (95% CI 0.490-0.900, p < 0.01). Conclusion: The ACE gene ID genotype has a significant association with PTB and is a protective factor for PTB. A larger sample set and functional studies are required to further elucidate of our findings.

The microRNApolymorphisms inmiR-150 and miR-1179 are associated with risk of idiopathic recurrent pregnancy loss

RESEARCH QUESTION

Are single nucleotide polymorphisms of microRNAs (miRNAs) and risk of idiopathic recurrent pregnancy loss (RPL) associated?

DESIGN

A total 375 patients with idiopathic RPL (age, mean ± standard deviation [SD] 33.02 ± 4.24 years; body mass index [BMI], mean ± SD, 21.57 ± 3.70 kg/m²) and 276 control participants (age, mean ± SD, 33.01 ± 5.27 years; BMI, mean ± SD, 21.58 ± 3.20) were recruited. Pregnancy loss was diagnosed using human chorionic gonadotrophin concentrations, ultrasonography and/or physical examination prior to 20 weeks of gestation. The genotype of the participants was determined by polymerase chain reaction restriction fragment length polymorphism analysis. Statistical analysis was performed to investigate the differences in frequencies between the control and RPL genotypes RESULTS: The miR-150G>A heterozygous genotype was significantly associated with increased risk of RPL (adjusted odds ratio 2.502, 95% confidence interval 1.555-4.025; P = 0.0002). The miR-1179A>T heterozygous genotype was significantly associated with decreased risk of RPL (adjusted odds ratio 0.633, 95% confidence interval 0.454-0.884; P = 0.007). Some allele combinations that included miR-150A or miRNA-1179T resulted in an increase or decrease in risk of RPL, respectively.

CONCLUSIONS

The miR-150G>A and miR-1179A>T polymorphisms were more frequently associated with RPL compared with controls.

Association study of the three functional polymorphisms (TAS2R46G>A, OR4C16G>A, and OR4X1A>T) with recurrent pregnancy loss

This study was purposed to investigate whether genetic polymorphisms in the function of stop-gain are associated with a fetal or placental development play roles and a development of idiopathic recurrent pregnancy loss (RPL) in Korean females. Three stop-gain polymorphisms were selected using next-generation sequencing screening, which allows for the rigorous examination and discovery of previously uncharacterized stop-gain genes and stop-gain expression profiles. Accordingly, we investigated the association of stop-gain polymorphisms in Korean women with RPL. Three functional polymorphisms in the TAS2R46G>A (rs2708381), OR4C16G>A (rs1459101), and OR4X1A>T (rs10838851) genes were genotyped using polymerase chain reaction (PCR)-restriction fragment length polymorphism assays and real-time PCR analysis. We determined that the OR4C16G>A polymorphism was associated with idiopathic RPL in Korean women (Adjusted odds ratio [AOR] 1.782; 95% confidence interval [CI] 1.004-3.163; P = 0.048, and AOR 1.766; 95% CI 1.020-3.059; P = 0.042). In addition, the prevalence of RPL was increased in women with the OR4C16GA + AA genotype and blood coagulation measures of prothrombin time (PT) > 10.4 s (AOR 8.292; 95% CI 2.744-25.054). We suggest that the OR4C16G>A polymorphism might serve as a clinically useful biomarker for the development, prevention, and prognosis of RPL.

The association of renin-angiotensinogen system genes polymorphisms and idiopathic recurrent pregnancy loss

The most common complication of pregnancy is idiopathic recurrent pregnancy loss (RPL). To identify the contribution of gene polymorphisms to this condition, we evaluated the association between RPL and the angiotensinogen (AGT), angiotensin receptor 1 (AGTR1) and Angiotensinogen converting enzyme (ACE). In this case-control study, the frequency of AGT (rs4762 and rs699), AGTR1 (rs5186) and ACE insertion/deletion (rs4340) polymorphisms in 202 idiopathic RPL women was compared with 210 women with no history of abortion, using tetra-primer ARMS-PCR. Polymorphisms were analysed by logistic regression analysis according to inheritance models. The CT genotype of AGT rs4762, the CC genotype of AGT rs699 and the AC genotype of AGTR1 rs5186 in a co-dominant inheritance model were associated with idiopathic RPL (OR = 1.63, 95% CI = 1.07-2.49 of CT versus CC; OR = 5.97, 95% CI = 1.28-27.82 of CC versus TT; and OR = 1.99, 95% CI = 1.22-3.07 of AC versus AA). The allele frequency of AGT rs699 and AGTR1 rs5186 polymorphisms, but not AGT rs4762 and ACE rs4340 polymorphisms were significantly different between women with RPL patients and controls (p = 0.020, p = 0.003, p = 0.105 and p = 0.065, respectively). These results show that there is a significant relationship between AGT (rs699) and AGTR1 (rs5186) polymorphisms and idiopathic RPL in the Iranian population.

MTHFR 3'-untranslated region polymorphisms contribute to recurrent pregnancy loss risk and alterations in peripheral natural killer cell proportions

Objective

To identify the associations between polymorphisms of the 3′-untranslated region (UTR) of methylenetetrahydrofolate reductase (MTHFR) gene, which codes for an important regulatory enzyme primarily involved in folate metabolism, and idiopathic recurrent pregnancy loss (RPL) in Korean women.

Methods

The study population comprised 369 RPL patients and 228 controls. MTHFR 2572C>A, 4869C>G, 5488C>T, and 6685T>C 3′-UTR polymorphisms were genotyped by polymerase chain reaction-restriction fragment length polymorphism analysis or by TaqMan allelic discrimination assays. Natural killer cell proportions were determined by flow cytometry.

Results

The MTHFR 2572-5488-6685 (A-C-T) haplotype had an adjusted odds ratio of 0.420 (95% confidence interval, 0.178–0.994; p=0.048) for RPL. Analysis of variance revealed that MTHFR 4869C>G was associated with altered CD56⁺ natural killer cell percentages (CC, 17.91%±8.04%; CG, 12.67%±4.64%; p=0.024) and folate levels (CC, 12.01±7.18 mg/mL; CG, 22.15±26.25 mg/mL; p=0.006).

Conclusion

Variants in the 3′-UTR of MTHFR are potential biomarkers for RPL. However, these results should be validated in additional studies of ethnically diverse groups of patients.

Lack of Association between Angiotensin Converting Enzyme I/D Polymorphism and Unexplained Recurrent Miscarriage in Saudi Arabia

BACKGROUND

An insertion/deletion (I/D) polymorphism in the angiotensin converting enzyme (ACE) gene has been associated with recurrent miscarriage (RM) in several populations. We initiated this study to determine the association, if any, between the I/D polymorphism of ACE gene and RM in Saudi females.

METHOD

This study was conducted on 61 Saudi females suffering from RM (mean age: 34.1±6.2 years; range 15-45) attending clinics at King Khalid University Hospital, and 59 age matched females who had at least 2 children, as controls. Blood samples were drawn in EDTA tubes by venipuncture. DNA was extracted using the Puregene DNA purification kits. Insertion/Deletion (I/D) polymorphism of ACE gene was investigated by amplifying the genomic DNA by PCR using gene-specific primers. A single 190 bp or 490 bp band was obtained in the homozygous cases for the D allele or I allele, respectively, while the presence of both 190 and 490 bp bands indicated heterozygosity (ID).

STATISTICAL ANALYSIS

Deviation from Hardy-Weinberg equilibrium was determined (http://ihg.gsf.de/cgi-bin/hw/hwa1.pl). A standard chi-square (χ²) test was used for comparing the genotype and allele frequencies in the two groups and Students't' test and χ² test were employed to compare values between the two groups. P<0.05 was considered statistically significant.

RESULTS

The frequencies of DD, ID, and II genotypes were 56.7%, 29.5% and 4.9%, respectively, in females with RM and 54.2%, 42.3% and 3.3% respectively in the control group, but the difference was not statistically significant.

CONCLUSION

In some populations, meta-analyses showed an association between I/D polymorphism and RM risk, and the D allele was implicated as an increased risk factor for RM. However, this association was not apparent in the Saudi females.

An Association Study of the SLC19A1 Gene Polymorphisms/Haplotypes with Idiopathic Recurrent Pregnancy Loss in an Iranian Population

AIMS

The genetics of folate metabolism is one of the most significant mechanisms influencing fetal growth and may underlie some cases of unexplained recurrent miscarriage. Reduced folate carrier 1, encoded by the SLC19A1 gene, is a transporter of folate. Folate deficiency and elevated levels of homocysteine could be disadvantageous for the female reproductive system health. Thus, the balance between homocysteine and folate status can be used to measure the risk of recurrent pregnancy loss.

METHODS

The purpose of this study was to determine the association between -43T>C, 80G>A, and 696C>T polymorphisms of the SLC19A1 gene in 147 women who had unexplained recurrent miscarriage in comparison with 150 healthy women. Amplification refractory mutation system-polymerase chain reaction was used to genotype the molecular polymorphisms of this gene.

RESULTS

The results indicated that the -43T>C single nucleotide of the SLC19A1 gene was significantly associated with a risk of recurrent miscarriage in Iranian women (p < 0.05). No significant association was observed for the other two polymorphisms. The haplotype frequency distribution of -43C/80G/696C, -;43C/80G/696T, -43C/80G, and 80G/696T was significantly different in patients than controls, which may represent a novel risk factor for idiopathic recurrent pregnancy loss.

CONCLUSIONS

Polymorphisms and haplotypes of the SLC19A1 gene can be considered risk factors for idiopathic recurrent pregnancy loss.

Insertion/deletion polymorphism in intron 16 of ACE gene in idiopathic recurrent spontaneous abortion: case-control study, systematic review and meta-analysis

The insertion/deletion (I/D) polymorphism in intron 16 of the angiotensin I-converting enzyme gene (ACE) has been extensively studied as a predisposing factor for idiopathic recurrent spontaneous abortion (IRSA). A case-control study including 149 women with ≥3 spontaneous abortions and 149 controls was performed to test the association of ACE I/D polymorphism with IRSA. A systematic review was conducted of previous case-control studies, with strict selection criteria for meta-analyses. We also aimed to evaluate the potential differences in summary estimates between studies defining IRSA as ≥2 and ≥3 spontaneous abortions. Genotyping was performed by PCR, and systematic review conducted using PubMed and Scopus. There was no association of the polymorphism with IRSA in Slovenian women. Sixteen case-control studies, showing substantial differences regarding IRSA definition and selection criteria for women were identified. Meta-analysis was performed and included four studies defining IRSA as ≥2 spontaneous abortions and the current study, which defined IRSA as ≥3 spontaneous abortions. Based on random effects model, meta-analysis conducted on 1192 patients and 736 controls showed no association with IRSA under dominant(DD+IDvsII) and recessive(DDvsID+II) genetic models. Well-designed studies are needed to evaluate the role of ACE I/D polymorphism in IRSA defined as ≥3 spontaneous abortions.

Genetic variants in microRNA machinery genes are associated [corrected] with idiopathic recurrent pregnancy loss risk

Objective

Key molecules involved in microRNA (miRNA) biogenesis, such as DROSHA, XPO5, and DICER, have been identified in trophoblast cells, confirming that the miRNA biogenesis pathway is active in human placenta. In addition, miRNAs regulate uterine gene expression associated with inflammatory responses during the peri-implantation period and participate in maternal-fetal immune tolerance. The purpose of this study was to demonstrate whether genetic polymorphisms in miRNA machinery genes show an association with idiopathic recurrent pregnancy loss (RPL) in Korean women.

Study design

We performed a case-control study with 238 controls and 338 women who had experienced at least two consecutive pregnancy losses between 1999 and 2010. Genotypes of miRNA machinery genes, including DICER rs3742330, DROSHA rs10719, RAN GTPase (RAN) rs14035, and exportin-5 (XPO5) rs11077 were analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. The logistic odds ratios (ORs) of RPL were estimated with a 95% confidence interval (CI) in multivariate analysis after maternal age adjustment. Gene-gene interactions among the loci of the four gene polymorphisms were evaluated using the multifactor dimensionality reduction (MDR) method.

Results

The RAN rs14035 CC genotype and DICER rs3742330/DROSHA rs10719 GG/TC+CC, rs3742330/RAN rs14035 GG/CC, and DICER rs3742330/XPO5 rs11077 GG/AC+CC combinations were significantly associated with increased RPL risk, whereas the RAN rs14035 CT, DICER rs3742330/RAN rs14035 AA+AG/CT+TT, DROSHA rs10719/RAN rs14035 TC+CC/CT+TT, and RAN rs14035/XPO5 rs11077 CT+TT/AA combinations reduced RPL risk. The A-T-T-C and G-C-T-A allele combinations (DICER/DROSHA/RAN/XPO5) were 20 times more frequent in the RPL group than in the control group.

Conclusion

Our study demonstrates the relationship between RPL development and the polymorphism of the miRNA machinery gene RAN and combined genotype of DROSHA/DICER.

Significant association between angiotensin-converting enzyme gene insertion/deletion polymorphism and risk of recurrent miscarriage: a systematic review and meta-analysis

BACKGROUND

Many studies have investigated the association between angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism and risk of recurrent miscarriage, but the impact is unclear due to inconsistencies among those studies. This study aimed to quantify the strength of the association between ACE I/D polymorphism and recurrent miscarriage risk by performing a systematic review and meta-analysis.

DESIGN AND METHODS

We searched PubMed, Embase, Web of Science, and Wanfang Medicine databases for eligible articles relating the association between ACE I/D polymorphism and risk of recurrent miscarriage in humans. We estimated the summary odds ratios (ORs) with their 95% confidence intervals (95% CIs) to assess the association.

RESULTS

Eleven studies with a total of 3357 individuals were included in this meta-analysis. Compared to the ACE II genotype, DD and ID were both associated with increased risk of recurrent miscarriage (OR DD versus II=1.81, 95% CI 1.23-2.66, P=0.003; OR ID versus II=1.50, 95% CI 1.25-1.80, P<0.001). Sensitivity analyses further confirmed the association above. No evidence of publication bias was observed.

CONCLUSION

Meta-analyses of available data show a significant association between ACE I/D polymorphism and recurrent miscarriage risk, and the ACE polymorphic D allele contributes to increased risk of recurrent miscarriage.

Methylenetetrahydrofolate Reductase C677T and A1298C Mutations in Women with Recurrent Spontaneous Abortions in the Northwest of Iran

Introduction. Recurrent spontaneous abortion (RSA) is a significant obstetrical complication that may occur during pregnancy. Various studies in recent years have indicated that two common mutations (C677T and A1298C) of the methylenetetrahydrofolate reductase (MTHFR) gene are risk factor for RSA. This study was carried out to determine the influence of (C677T and A1298C) of the methylenetetrahydrofolate reductase (MTHFR) gene mutations with RSA. Materials and Methods. A total of 139 women were included in this study: 89 women with two or more consecutive miscarriages and 50 healthy controls. Total genomic DNA was isolated from blood leukocytes. To determine the frequency of the two common C677T and A1298C MTHFR gene mutations in the patients and controls, we used two methods, amplification refractory mutation system-PCR and PCR-restriction fragment length polymorphism. Results. There is no significant difference in the prevalence of 677T/T genotype among women with RSA and healthy controls (P = 0.285). Also no statistically significant difference in the frequency of A1298C MTHFR gene mutation was detected between the two groups (P = 0.175 ). Conclusion. In conclusion, the results indicate that the Amplification Refractory Mutation System-PCR method was in complete concordance with the results obtained by standard PCR-restriction fragment length polymorphism method. The results also show no significant difference in MTHFR C677T/A1298C genotype distribution among the two groups; therefore, further studies on larger population and other genetic variants to better understand the pathobiology of RSA are needed.

Angiotensin-converting enzyme insertion/deletion (I/D) polymorphisms and recurrent pregnancy loss: a meta-analysis

BACKGROUND

Recurrent pregnancy loss (RPL) had said to be related to the angiotensin converting enzyme insertion/deletion polymorphisms (ACE I/D) gene polymorphisms. But the conclusions were controversial. This meta-analysis was conducted to investigate the real association in ACE I/D polymorphisms and RPL firstly.

METHODS

Combine Pubmed Embase and HuGENet database in data analysis for this meta-analysis from October 2000 to November 2011. The metagen system was used to select the models and effects. Odds ratio (OR) with 95% confidence interval (CI) was used to assess the strength of this association.

RESULTS

9 studies from six countries with 1264 RPL and 845 controls were included according to our criterion. Following the metagen system, we used the dominant model with random effects. The summary OR =1.61 (95% CI: 1.10-2.36, I (2) = 59.0%), which suggested the ACE D allele might increase the RPL risk in Asia (OR=1.97, 95% CI: 1.31-2.98, I (2) = 44.4%), among Asians (OR=1.69, 95% CI: 1.06-2.36, I (2) =32.7%). In additional, after conducting sensitivity analysis, the results had no differences except for Caucasian subgroup reached to the significance (OR=2.059, 95% CI: 1.455-2.914), so we couldn't ignore the relationship between the polymorphisms of ACE D/I gene and Caucasians yet. There seemed no publication bias in our eligible studies with Begg's test (P = 0.867).

CONCLUSIONS

Results in this meta-analysis presented the positive function of the ACE I/D polymorphism in increasing the RPL risk. Furfure prospective studies were needed to confirm the precise relationship between the ACE I/D and RPL.