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

Abstract

Purpose 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. Methods 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 Blate^fetal losses, and >15th gestation week subgroups.Results 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. Conclusion This study confirmed the proposed role of M2/ ANXA5 as embryonic, genetically associated thrombophilia predisposition factor for early RPL among ethnic Malay of Malaysia.Keywords Annexin A5 . M2/ANXA5 . Recurrent pregnancy loss (RPL) . MiscarriageElectronic supplementary material The online version of this article

Assessment of M2/ANXA5 haplotype as a risk factor in couples with placenta-mediated pregnancy complications

“…Fetal involvement of the M2 allele of ANXA5 in placental obstetric complications was first documented for IUGR patients [17], followed by a report on PE [12], whereby reduced expression of the natural anticoagulant ANXA5 was described in chorion of IUGR and PE patients, independent of M2 parental origin. Genetic evidence substantiated the role of the paternal ANXA5 promoter genotype with elevated M2 IUGR intrauterine growth restriction, PB premature birth, PE preeclampsia, PopGen Muenster and Munich control groups, % percentage, n count a Genotype M1/M2 was only observed in one PB, one PE, and in two IUGR couple partners, three Munich and five PopGen controls carrier rates of male partners of RPL women, first in a pilot research [20] and further in following larger scale population investigations [9,10,14].…”

“…In the last decade, genetic and functional studies characterized a constellation of four consecutive single nucleotide variants comprised of the minor alleles of SNPs rs112782763, rs28717001, rs28651243, and rs113588187 in the proximal promoter region of ANXA5 gene, c.-467G>A, c.-448A>C, c.-422T>C, and c.-373G>A. This constellation, inherited as a haplotype confirmed through molecular cloning and termed M2 in 2007 [7], was associated with increased risk for adverse pregnancy outcome in patient cohorts of European [3,[7][8][9][10], Asian [11,12], and Austronesian origin [13,14]. M2/ANXA5, a risk factor for susceptibility to recurrent pregnancy loss (RPL) with a prevalence of about 15% in the general European population [3,7,9,10], was designated RPRGL3, OMIM entry 614391 and concomitant expression studies evaluated its influence on ANXA5 levels.…”

“…The first indication of such a contribution came from an expression study of ANXA5 mRNA, where lowered M2 allele specific levels were confirmed independent of parental origin in chorion of intrauterine growth restriction (IUGR) patients [17]. An initial pilot study in RPL couples gave primary independent confirmation of a similar risk attributed to paternal M2 alleles [20], followed by studies in larger European cohorts [9,10] and Malaysian research [14]. Considering the potential importance of paternal M2 allele in the diagnostic work up of adverse pregnancy outcomes, this study was carried out where the aim was to test the associated risk contribution in couples with PE, IUGR, and premature births (PB).…”

The male contribution to recurrent pregnancy loss

“…It has also recently been demonstrated that the genetic frequency of paternal M2 carriage is significantly higher in couples with RPL than in fertile controls in the German population and its effects occur distinctly between the 10th and 15th week of gestation ( 75 , 78 ). Association between Annexin A5 M2 haplotype polymorphism and RPL has been replicated in other populations including Italian, Bulgarian, Japanese and Malaysian but the mechanism by which it impacts pregnancy loss needs to be further elucidated ( 78 - 81 ). Genotypic evaluation of embryonic tissue obtained from pregnancy loss may be relevant in further understanding the impact of this haplotype.…”

Micromolar Zinc in Annexin A5 Anticoagulation as a Potential Remedy for RPRGL3- Associated Recurrent Pregnancy Loss

“…14,15 Accumulated genetic evidence demonstrated significant enrichment of the haplotype observed in RPL patient groups, contributing to relative risks for carriers from 1.5 to 2, compared to random population controls, and of 1.8 to 3, compared to healthy selected controls of German, Italian, Bulgarian, United Kingdom, Japanese, and Malaysian ethnic backgrounds. 16 Reduction of ANXA5 expression through carrier status of the M2 haplotype has been demonstrated to mostly influence the stage of early fetal losses between weeks of gestation 10 and 15, [17][18][19] a time frame of embryonic development characterized with transition of high-to low-resistance placental vasculature, 20 parallel to the timing of fetal loss observed in the murine model. 10 First indications of successful anticoagulant treatment of M2/ANXA5 carriers with low-molecular-weight heparin (LMWH) came from multicenter randomized trials on RPL patients 16 and in vitro fertilization (IVF) couples.…”