M2 Carriers Research Articles

Maternal and paternal carriage of the annexin A5 M2 haplotype: a possible risk factor for recurrent implantation failure (RIF)

ObjectiveThis study was carried out to determine the potential role of the M2/ANXA5 haplotype as a risk factor for recurrent implantation failure (RIF). Carriage of the M2/ANXA5 haplotype that induces prothrombotic changes has been implicated in failure of early pregnancies and placenta-mediated complications (preeclampsia, IUGR, preterm birth).Material and methodsIn the present case control study, 63 couples (females and males) with RIF presenting for IVF/ICSI to the Fertility Center of [masked] were analyzed. RIF was defined as ≥ 4 consecutive failed ART-transfers of ≥ 4 blastocysts or ≥ 8 cleavage-stage embryos of optimal quality and maternal age ≤ 41. Fertile female controls (n = 90) were recruited from the same center. Population controls (n = 533) were drafted from the PopGen biobank, UKSH Kiel.ResultsCouples carrying the M2/ANXA5 haplotype turned out to have a significantly increased relative risk (RR) for RIF. Compared with female fertile controls, RR was 1.81 with p = 0.037 (OR 2.1, 95%CI 1.0–4.3) and RR was 1.70, with p = 0.004 (OR 2.0, 95%CI 1.2–3.1) compared with population controls (15.4% M2 carriers). Male partners were comparable with RIF females for M2/ANXA5 haplotypes (28.6% vs. 23.8%, p = 0.54). RIF females compared with population controls had a RR of 1.55 (p = 0.09) and RIF males compared with population controls had a RR of 1.9 (p = 0.01). Couples with ≥ 7 failed transfers showed a RR of 1.82 (p = 0.02) compared with population controls.ConclusionOur findings suggest that maternal as well as paternal M2/ANXA5 haplotype carriages are risk factors for RIF. These results allow new insights into the pathogenesis of RIF and might help to identify relevant risk groups.

Genetic variations and haplotypes in the annexin A5 gene are associated with the risk of recurrent pregnancy loss.

The expression of annexin A5 (ANXA5) was shown to affect the pathogenesis of recurrent pregnancy loss (RPL). In this study, the effects of two haplotypes, M1 and M2, on the transcription efficiency of ANXA5 promoter were explored. Correlation analysis was used to investigate the association between the single-nucleotide polymorphism haplotypes in ANXA5 promoter and the risk of RPL. And a luciferase reporter assay was carried out to study the effects of haplotypes M1 and M2 on the transcription efficiency of the ANXA5 promoter. To study the association between ANXA5 haplotypes and the risk of RPL, real-time polymerase chain reaction, western blot analysis, and immunohistochemistry assays were conducted to observe the expressions of ANXA5 messenger RNA (mRNA) and protein. Compared to M1 haplotype carriers, M2 haplotype carriers were associated with a higher risk of RPL. Additionally, compared to GATGTC haplotype carriers, GATGGC haplotype carriers were associated with a higher risk of RPL. Compared with RPL cases, the incidences of M2 haplotype were lower in both the population control and parous control cases. Furthermore, M2 carriers showed more significantly decreased activity of ANXA5 promoter compared to the carriers of other haplotypes, indicating that the haplotypes of ANXA5 promoter may be used as a potential biomarker to predict the prognosis of RPL. Moreover, the activity of ANXA5 as well as the mRNA/protein expression of ANXA5 was significantly downregulated in RPL patients, indicating that the M2 haplotype significantly increased the risk of RPL. Therefore, haplotype M2 increased the risk of RPL by inhibiting the expression of ANXA5.

Antiphospholipid Antibodies in a General Obstetric Population: Clinical Impact on Pregnancy Outcome and Relationship with the M2 Haplotype in the Annexin A5 (ANXA5) Gene.

Antiphospholipid (aPL) antibodies are recognised risk factors for adverse obstetric outcomes. Recently, carriers of the M2 haplotype in the Annexin A5 gene have been shown to have a higher susceptibility to develop aPL antibodies. In a general obstetric population, we prospectively evaluated the possible relationship between: (1) aPL antibodies and M2 haplotype; and (2) aPL antibodies and/or M2 haplotype and obstetric outcomes. From a cohort of 3,097 consecutive pregnant women, 1,286 samples were analysed for the presence of both anti-cardiolipin and anti-human β2-glycoprotein I antibodies; samples with available DNA (n = 606) were also investigated for the M2 haplotype. Overall, 41/1,286 (3.2%) women showed the presence of aPL antibodies. Among them, 2 (4.8%) experienced a pregnancy loss and 38 (92.7%) gave birth to live-born babies (p-value = non-significant vs. those without aPL antibodies). M2 haplotype was identified in 140 (23.1%) out of 606 women with DNA available: 3/140 (2.1%) M2 carriers and 17/466 (3.6%) non-carriers tested positive for aPL antibodies, respectively (p-value = non-significant). In total, 15/150 (10%) M2 and/or aPL antibody carriers, and 38/445 (8.5%) non-aPL antibody and/or M2 carriers suffered from obstetric complications, respectively (p-value = non-significant). No relationship between aPL antibodies and M2 haplotype was found. Furthermore, neither aPL antibodies nor the M2 haplotype is associated with obstetric complications.

Genetic analysis of the M2/ANXA5 haplotype as recurrent pregnancy loss predisposition in the Malay population.

The aim of this study was to evaluate a new predisposition factor, M2/ANXA5 (RPRGL3), in recurrent pregnancy loss (RPL) patients of Malay origin, since it was previously known that the prevalence of this condition is relatively high among the Malay population of Malaysia, where conventional hereditary thrombophilia factors have been generally ruled out. A total of 232 women who had experienced ≥2 unexplained RPL and 141 available male partners were recruited, with 360 healthy Malay and 166 parous female controls. Prevalence of M2 carriage and RPL odds ratios were calculated in (a) control and patient groups; (b) clinically defined subgroups in categories of pregnancy loss, primary, secondary, and tertiary; and (c) timing of pregnancy loss in early, ≤15th gestation week and "late" fetal losses, and >15th gestation week subgroups. Both male and female subjects had similar M2/ANXA5 allele frequencies. The carrier rate of M2/ANXA5 for the general Malay population was 42.2 and 34.9% for parous controls. These carrier rates compared to Malay RPL subjects (52% M2 carriers) resulted in elevated odds ratios (95% confidence interval) of 1.53 (1.1 to 2.1) and 1.97 (1.3 to 3.1) accordingly for early fetal losses. Moreover, exceeding copy numbers of M2/ANXA5 alleles seemed to afflict a greater chance of RPL in couples, especially when both partners were M2 carriers. This study confirmed the proposed role of M2/ANXA5 as embryonic, genetically associated thrombophilia predisposition factor for early RPL among ethnic Malay of Malaysia.

Precision Medicine in Assisted Conception: A Multicenter Observational Treatment Cohort Study of the Annexin A5 M2 Haplotype as a Biomarker for Antithrombotic Treatment to Improve Pregnancy Outcome

BackgroundPregnancy failure and placenta mediated pregnancy complications affect >25% of pregnancies. Although there is biological plausibility for a procoagulant mechanism underlying some of these events, antithrombotic intervention trials demonstrate limited benefit, possibly through lack of stratification in heterogeneous patient groups. The ANXA5 M2 haplotype is a possible procoagulant biomarker and was tested pragmatically to determine whether this screening and LMWH treatment normalized the outcome for ANXA5 M2 positive couples.This was a pragmatic study that aimed to measure the effectiveness of a testing (for the M2 haplotype) and treatment (LMWH) pathway in routine clinical practice where there is variation between patients. Such a study in couples with fertility problems can inform choices between treatments; it is then the management protocol which is the subject of the investigation, not the individual treatments. MethodsCouples (N=77) with one or both partners ANXA5 M2 positive demonstrated association of this haplotype with adverse IVF outcome. A pragmatic, multicenter, prospective cohort study of ANXA5 M2 haplotype screening, and LWMH treatment following embryo transfer (ET) in 103 IVF couples positive for ANXA5 M2 was performed. They were compared with a group of 1000 contemporaneous randomly selected unscreened and untreated couples undergoing assisted conception, from which 103 matched control couples were derived. The primary outcome measure was live birth incidence. Secondary outcomes were results following embryo transfer (ET) and live birth outcome by gender and M2 carriage, and allelic dose influence. FindingsThe tested and treated cohort of ANXA5 M2 carriers achieved a similar live birth rate (37.9%) per ET cycle compared to both the more fertile comparison group (38.5%), and to the 103 matched controls (33.0%). Significantly more treated male carrier only couples had a live birth versus female M2 only (47.7% vs. 25.0% p=0.045). InterpretationPragmatic ANXA5 M5 screening and treatment with LMWH in couples undergoing IVF is associated with similar outcome to couples with more favorable prognostic factors. The difference in live birth outcome for treated male only carrier couples may be consistent with an additional maternal thrombophilic factor that may adversely affect pregnancy, although other mechanisms are possible. This study suggests that LMWH treatment should be started prior to clinical pregnancy.

Multicentre study of the clinical relevance of screening IVF patients for carrier status of the annexin A5 M2 haplotype

Thrombophilia and impaired placental vasculature are a major cause of adverse pregnancy outcome. In 2007, a new hereditary factor for obstetric complications and recurrent pregnancy loss (RPL) was identified as a sequence variation in the core promoter of the annexin A5 gene, ANXA5, called the M2 haplotype. M2 carriership has been demonstrated in couples with recurrent miscarriage and its origin is embryonic rather than specifically maternal, confirmed by subsequent papers. The M2 haplotype is the first report of a hereditary factor related to pregnancy pathology caused by embryonic-induced anticoagulation. It has been demonstrated that couples with RPL had equal and significantly increased M2 carriership and that maternal and paternal carriership confers equal risk. Given its importance for patients with RPL, and potentially implantation failure, this study assessed the incidence of carrier status for the M2 ANXA5 haplotype in both the male and female of couples attending five CARE IVF centres. In 314 patients (157 couples), 44% of couples (one or both partners), 24% of females, 26% of males and 37% of couples with unexplained infertility were M2 carriers. This high incidence has provoked further urgent studies on specific patient populations and on the value of post embryo-transfer therapy.

Lower Incidence of M2/ANXA5 Carriage in Recurrent Pregnancy Loss Patients With Elevated Lipoprotein(a) Levels

This study compared the incidence of M2/ANXA5 haplotype carriage, a documented repeated miscarriage risk factor, in patient groups with normal and elevated lipoprotein(a) (Lp(a)) levels. A total of 138 women with ≥2 consecutive, idiopathic recurrent miscarriages, categorized in patients with elevated (≥30 mg/dL, n = 44) and normal Lp(a) level (<30 mg/dL, n = 94) were recruited at the recurrent pregnancy loss (RPL) clinic of Munich Großhadern University Hospital. A total of 500 fertile women served as controls. All patients were genotyped for ANXA5 promoter haplotypes, genetic frequencies were compared, and odds ratios (ORs) and relative risks of M2 carriers were calculated. Women with M2 haplotype had an almost 2 times higher relative risk of RPL (OR 2.6, 95% confidence interval 1.5-4.6, P = .001) than fertile controls. Furthermore, risk rises to 2.47 in patients having normal Lp(a) levels (OR 3.2, 95% confidence interval 1.7-5.9, P = .001), whereas women with high Lp(a) levels exhibit notably lower apparent RPL risk of 1.39 (OR 1.4, 95% confidence interval 0.5-4.1, P = .659).

Contribution of fetal ANXA5 gene promoter polymorphisms to the onset of pre-eclampsia

ObjectiveA common haplotype M2 consisting of minor SNP alleles located in the ANXA5 gene promoter region has been described as a risk factor for various obstetric complications such as recurrent pregnancy loss, pre-eclampsia and pregnancy-related thrombophilic disorder. However, the question of whether it is the maternal or fetal genotype that contributes to the onset of these disorders remains to be resolved. MethodsWe analyzed ANXA5 gene variants in the blood and placental tissues from pre-eclampsia patients and normotensive controls. ANXA5 expression was examined by qRT-PCR, Western blotting and immunostaining. Results were compared between M2 and non-M2 carriers. ResultsThe M2 haplotype was found to be significantly frequent in placentas from pre-eclamptic patients relative to the controls (25.5% versus 10%, P = 0.044), In contrast, no significant differences were observed in maternal blood (13.0% versus 11.3%, P = 0.597). The placental expression of ANXA5 mRNA was found to be lower in M2 carriers. When examined by Western blot and immunostaining, the ANXA5 protein levels were found to be affected more by the placental than the maternal genotype. Histological examination of the placentas from the pre-eclamptic patients demonstrated that a placental M2 haplotype correlated more closely than maternal M2 with the severity of perivillous fibrin deposition. ConclusionsAlthough preliminary, these results suggest that hypomorphic M2 alleles in the in placental ANXA5 promoter, whether transmitted maternally or paternally, might be an essential determinant of an increased risk of pre-eclampsia via local thrombophilia at the feto–maternal interface.

Independent association of the M2/ANXA5 haplotype with recurrent pregnancy loss (RPL) in PCOS patients

ObjectiveThe aim of this study was to analyze the contribution of the M2 haplotype of ANXA5 gene, previously identified as a risk factor for RPL and thrombophilia related pregnancy complications, to repeated miscarriage observed in PCOS patients. Patients/Methods100 PCOS patients, 500 fertile women and 533 random population controls were genotyped for M2/ANXA5. ResultsM2 haplotype carriers faced a 3.4 fold elevated RPL risk (odds ratio 5.3, 95% confidence interval 3–9.2) compared to female fertile controls and 2.1 (odds ratio 2.6, 95% confidence interval 1.6–4.3) compared to population controls. The relative population risks in subgroups of PCOS patients with primary and secondary RPL were 2.3 (odds ratio 2.5, 95% confidence interval 1.2–5) and 3.3 (odds ratio 3.6, 95% confidence interval 1.5–8.4) respectively. As compared to the fertile women group, the relative risks equaled 4 (odds ratio 5, 95% confidence interval 2.3–10.8) and 6 (odds ratio 7.2, 95% confidence interval 3–17.7). Estimated relative risks for M2 carriers among PCOS RPL patients matched the values previously obtained for repeated miscarriage populations. The essential phenotypes, clinically defining PCOS, associated neither with RPL in their diagnostically relevant combinations, nor with M2 carriage as RPL risk factor in the PCOS RPL subgroups. ConclusionsM2/ANXA5 seems an independent RPL risk factor in PCOS patients that progressively correlates with the number of first trimester pregnancies. From our pilot study in PCOS women it appears relevant to offer M2/ANXA5 diagnostic analysis to such patients with RPL complications, to possibly guide proper therapeutic decisions.