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

PURPOSE: The aim of this study was to confirm the associated M2/ANXA5 carrier risk in women with placenta-mediated pregnancy complications (PMPC) and to test their male partners for such association. Further analysis evaluated the influence of maternal vs. paternal M2 alleles on miscarriage. METHODS: Two hundred eighty-eight couples with preeclampsia (PE), intrauterine growth restriction (IUGR), or premature birth (PB) were recruited (n = 96 of each phenotype). The prevalence of the M2 haplotype was compared to two control cohorts. They included a group of women with a history of normal pregnancy without gestational pathology (Munich controls, n = 94) and a random population sample (PopGen controls, n = 533). RESULTS: Significant association of M2 haplotype and pregnancy complications was confirmed for women and for couples, where prevalence was elevated from 15.4 to 23.8% (p < 0.001). Post hoc analyses demonstrated an association for IUGR and PB individually. A strong link between previous miscarriages and M2 carrier status was identified which may explain the predisposition to placental pregnancy complication. M2/ANXA5 appears to be a risk factor for adverse pregnancy outcomes related, but not limited to miscarriages, with similar prevalence in women and their male partners. CONCLUSION: These findings support the proposed physiological function of ANXA5 as an embryonic anticoagulant that appears deficient in contiguous specter of thrombophilia-related pregnancy complications culminating more frequently in miscarriage in a maternal M2 carrier background.

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

Deficient expression of the placental anticoagulant annexin A5 (ANXA5) has been associated with thrombophilia-related pregnancy complications and ultimately with recurrent pregnancy loss (RPL). Carrier status of M2/ANXA5 ( RPRGL3), common ANXA5 promoter variant, has been identified as genetic cause of reduced ANXA5 levels and proposed as biomarker for successful anticoagulant treatment of RPL women. A murine model of AnxA5 loss of function displayed characteristic placental pathology and fetal loss that was alleviated through anticoagulant intervention. This study identified an alternative means of supplementing anticoagulation, through elevated ANXA5 expression. Physiological micromolar Zn2+ stimulated ANXA5 transcription, raising ANXA5 protein expression and surface abundance on BeWo and human umbilical vein endothelial cells (HUVEC), thus resulting in prolonged coagulation times. Zn2-fed AnxA5 functionally deficient pregnant mice showed a trend to increase litter size when primiparous that grew comparable to wild-type progeny in subsequent pregnancies. Elevated AnxA5 signal upon Zn2+ treatment was confirmed in murine placentae. Micromolar Zn2+ stimulated ANXA5 expression in cell culture directly and alleviated RPL in AnxA5 genetically deficient mice, without notable toxicity effects.

Chromosomal evolution of the PKD1 gene family in primates.

BACKGROUND: The autosomal dominant polycystic kidney disease (ADPKD) is mostly caused by mutations in the PKD1 (polycystic kidney disease 1) gene located in 16p13.3. Moreover, there are six pseudogenes of PKD1 that are located proximal to the master gene in 16p13.1. In contrast, no pseudogene could be detected in the mouse genome, only a single copy gene on chromosome 17. The question arises how the human situation originated phylogenetically. To address this question we applied comparative FISH-mapping of a human PKD1-containing genomic BAC clone and a PKD1-cDNA clone to chromosomes of a variety of primate species and the dog as a non-primate outgroup species. RESULTS: Comparative FISH with the PKD1-cDNA clone clearly shows that in all primate species studied distinct single signals map in subtelomeric chromosomal positions orthologous to the short arm of human chromosome 16 harbouring the master PKD1 gene. Only in human and African great apes, but not in orangutan, FISH with both BAC and cDNA clones reveals additional signal clusters located proximal of and clearly separated from the PKD1 master genes indicating the chromosomal position of PKD1 pseudogenes in 16p of these species, respectively. Indeed, this is in accordance with sequencing data in human, chimpanzee and orangutan. Apart from the master PKD1 gene, six pseudogenes are identified in both, human and chimpanzee, while only a single-copy gene is present in the whole-genome sequence of orangutan. The phylogenetic reconstruction of the PKD1-tree reveals that all human pseudogenes are closely related to the human PKD1 gene, and all chimpanzee pseudogenes are closely related to the chimpanzee PKD1 gene. However, our statistical analyses provide strong indication that gene conversion events may have occurred within the PKD1 family members of human and chimpanzee, respectively. CONCLUSION: PKD1 must have undergone amplification very recently in hominid evolution. Duplicative transposition of the PKD1 gene and further amplification and evolution of the PKD1 pseudogenes may have arisen in a common ancestor of Homo, Pan and Gorilla approximately 8 MYA. Reticulate evolutionary processes such as gene conversion and non-allelic homologous recombination (NAHR) may have resulted in concerted evolution of PKD1 family members in human and chimpanzee and, thus, simulate an independent evolution of the PKD1 pseudogenes from their master PKD1 genes in human and chimpanzee.

Annexin A5 interacts with polycystin-1 and interferes with the polycystin-1 stimulated recruitment of E-cadherin into adherens junctions.

Polycystin-1 is the gene product of PKD1, the first gene identified to be causative for the condition of autosomal dominant polycystic kidney disease (ADPKD). Mutations in PKD1 are responsible for the majority of ADPKD cases worldwide. Polycystin-1 is a protein of the transient receptor potential channels superfamily, with 11 transmembrane spans and an extracellular N-terminal region of approximately 3109 amino acid residues, harboring multiple putative ligand binding domains. We demonstrate here that annexin A5 (ANXA5), a Ca(2+) and phospholipid binding protein, interacts with the N-terminal leucine-rich repeats of polycystin-1, in vitro and in a cell culture model. This interaction is direct and specific and involves a conserved sequence of the ANXA5 N-terminal domain. Using Madin-Darby canine kidney cells expressing polycystin-1 in an inducible manner we also show that polycystin-1 colocalizes with E-cadherin at cell-cell contacts and accelerates the recruitment of intracellular E-cadherin to reforming junctions. This polycystin-1 stimulated recruitment is significantly delayed by extracellular annexin A5.

Effects of the factor V G1691A mutation and the factor II G20210A variant on the clinical expression of severe hemophilia A in children--results of a multicenter studys.

The present multicenter cohort study of 107 pediatric PUPs was performed to determine whether the concomitant inheritance of the factor (F) V G1691A or the F II G20210A mutation influences the clinical expression of severe hemophilia A (HA). Carriers of the FV and FII mutations had a significantly lower annual bleeding frequency (ABF) than non-carriers (p=0.012). Joint damage (Pettersson score) was significantly less severe in patients with thrombophilia (p=0.022). A protective effect of thrombophilic risk factors was shown for ABF (OR [CIs]: 0.7[0.5-0.9]; p=0.02) and the severity of the hemophilic arthropathy (OR [CIs]: 0.06[0.01-0.3]; p=0.0009).

A novel TACSTD2 gene mutation in a Turkish family with a gelatinous drop-like corneal dystrophy.

PURPOSE: To identify the molecular defect causing gelatinous drop-like corneal dystrophy in a Turkish family and assign affected and carriership status. METHODS: Visual activity of affected family members was measured using Snellen optotypes. To identify the molecular defect, mutation analysis of the TACSTD2 (M1S1) gene was performed. RESULTS: We report on a new TACSTD2 mutation, c.653delA, in a Turkish family. The identified molecular defect cosegregates with the disease among affected members of the family and is not found in 100 unaffected individuals of various ethnic origin. CONCLUSIONS: A few TACSTD2 gene mutations in the homozygous or compound heterozygous state have been described as causative for this abnormality, mainly in several Japanese families. The newly identified mutation is predicted to generate a shortened protein product, thereby completely altering the COOH-terminal region and deleting the transmembrane domain, required for anchoring at cell membranes and the phosphatidylinosyol2-binding site.

A common haplotype of the annexin A5 (ANXA5) gene promoter is associated with recurrent pregnancy loss.

We sought to verify whether variation in the promoter of the gene encoding placental anticoagulant protein annexin A5 (ANXA5) represents a risk factor for recurrent pregnancy loss (RPL). Sequence analysis of 70 German RPL patients, all known to carry neither factor V Leiden nor a prothrombin mutation, revealed four consecutive nucleotide substitutions in the ANXA5 promoter, which were transmitted as a joint haplotype (M2). Reporter gene assays revealed that M2 reduces the in vitro activity of the ANXA5 promoter to 37-42% of the normal level. The possible relationship between M2 and RPL was evaluated by comparing RPL patients with two independent control groups recruited from the registry of the Institut für Humangenetik in Münster and the PopGen biobank in Kiel, respectively. Carriers of M2 were found to exhibit a > 2-fold higher RPL risk than non-carriers (odds ratio, 2.42; 95% confidence interval, 1.27-4.58) when using unselected controls (PopGen) and an almost 4-fold higher risk when using the Münster 'super-controls', i.e. women with successful pregnancies and no previous history of pregnancy losses (odds ratio, 3.88; 95% confidence interval, 1.98-7.54). This statistically significant association should facilitate the development of improved prognostic algorithms for RPL, involving a more precise assessment of individual disease risks, and provide a guide to offering adequate therapies where relevant.

A splice form of polycystin-2, lacking exon 7, does not interact with polycystin-1.

Polycystin-2 (or polycystic kidney disease gene 2 product, PKD2) and its homologues are calcium-regulated ion channels. Mutations in PKD2 are causative for autosomal dominant polycystic kidney disease. Alternative splicing has been documented for the 'PKD2-like' genes as a naturally occurring event and for PKD2 in pathologic context. Here we studied naturally occurring PKD2/Pkd2 (human/murine) splice forms on the mRNA and protein levels. Systematic scanning of PKD2/Pkd2 cDNAs obtained through RT-PCR from murine tissues and human cell lines revealed alternative splice forms that were sequenced and checked for translation. We identified three major alternative transcripts of PKD2/Pkd2, PKD2/Pkd2Delta6, PKD2/Pkd2Delta7 and PKD2/Pkd2Delta9, and one minor splice form, PKD2/Pkd2Delta12-13, numbered according to deleted exons or parts thereof. A transcript lacking exon 7 (PKD2/Pkd2Delta7) generated significantly altered protein variant. This polycystin-2Delta7 protein appeared stable, when expressed in cell culture and apparently did not interact with polycyctin-1, which should be due to the reversed topology (extracellular) of the interacting C-terminus (intracellular in polycystin-2). Pkd2Delta7 transcript was predominantly expressed in brain and amounted to 3-6.4% of Pkd2 transcripts in the relevant organ. Moreover, both Pkd2 and Pkd2Delta7 were developmentally regulated. Polycystin-2Delta7 adds on to the number of identified polycystin molecules. The predominant expression in brain indicates a function in this organ. The inability to interact with polycystin-1 expands further the PKD1-independent functions of polycystin-2 forms.