Association between ABO haplotypes and the risk of venous thrombosis: impact on disease risk estimation

The Plasma Proteome and Risk of Future Venous Thromboembolism-Results from the HUNT Study

BACKGROUND

 This study aimed to identify novel plasma proteins associated with first-lifetime venous thromboembolism (VTE) and molecular pathways involved in VTE pathogenesis.

METHODS

 A case-cohort comprising incident VTE cases (n = 294) and a randomly sampled age- and sex-weighted subcohort (n = 1,066) was derived from the Trøndelag Health Study (HUNT3, n = 50,800). Blood samples were collected and stored at cohort inclusion (2006-2008), and participants were followed up to 5 years. Proteome-wide analyses was performed using the 7k SomaScan® proteomics platform, and weighted Cox-regression models adjusted for age, sex, and sample batch were conducted, with the Bonferroni method applied to account for multiple testing. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were applied on the top-ranked 200 proteins associated with VTE.

RESULTS

 Out of 7,288 human proteins, 7 proteins were significantly associated with higher VTE risk with p-value <6.9 × 10-6 (hazard ratios per 1 standard deviation increase in protein levels ranging from 1.39 to 1.86). Except for coagulation factor VIII and tumor necrosis factor soluble receptor II, these proteins were novel associations and included collagen alpha-3(VI):BPTI/Kunitz inhibitor, histo-blood group ABO system transferase, peroxidasin, human epididymis protein 4, and regulator of G protein signaling 3. KEGG analyses of the top-ranked 200 proteins revealed significant pathway enrichment of nine proteins in the complement (mainly lectin pathway) and coagulation (mainly intrinsic pathway) cascades.

CONCLUSION

 Our proteome-wide analysis led to discovery of five novel protein candidates associated with 5-year risk of future VTE. KEGG analyses supported an interplay between the complement and coagulation pathways in the pathogenesis of VTE.

Genomic Landscape of Thrombosis Recurrence Risk Across Venous Thromboembolism Subtypes

Venous thromboembolism (VT) is a frequent (annual incidence of 1 to 2 per 1,000) and potentially life-threatening (case-fatality rate up to 10%) disease. VT is associated with serious short-term and long-term complications including a recurrence rate of approximately 20% within five years. Anticoagulant therapy, the mainstay of VT treatment, drastically reduces the risk of early VT recurrence, but it exposes patients to a substantial risk of bleeding. We analysed the genomic architecture of VT recurrence using data from 6,571 patients across eight cohorts, 1,816 of whom experienced recurrence, with a particular focus on the clinical manifestation of the type of first VT event. Through genome-wide association studies (GWAS), we identified three loci significantly associated (P<5×10-8) with VT recurrence in the general VT population: GPR149/MME, L3MBTL4, and THSD7B. Protein Quantitative Trait Locus and Mendelian Randomization analyses further identified elevated plasma levels of coagulation factor XI and GOLM2 as risk factors for recurrence, while decreased levels of PCSK9 and pro-IL16 were linked to reduced VT recurrence risk. Subgroup analyses revealed 18 loci associated with VT recurrence, with notable differences between pulmonary embolism (PE) and deep vein thrombosis (DVT). For example, the exonic variant SLC4A1 p.Glu40Lys was significantly associated with recurrence in PE patients (Hazard Ratio (HR)=3.23, P=9.7×10-12) but showed no effect in DVT (HR=1.00, P=0.98). These findings emphasize the role of specific genetic loci and protein pathways in influencing VT recurrence and provide valuable insights into potential therapeutic targets. Further research is needed to clarify the biological mechanisms driving these associations.

High risk of long-term recurrence after a first episode of venous thromboembolism during pregnancy or postpartum: the REcurrence after a PrEgnAncy related Thrombosis (REPEAT) Study

BACKGROUND

The long-term recurrence risk after a pregnancy-associated venous thromboembolism (VTE) is sparsely assessed.

OBJECTIVES

To determine the rate of recurrence after a pregnancy-associated VTE and identify associated risk factors.

METHODS

Five hundred eighty-seven women with a history of first VTE occurring during pregnancy or up to 3 months after delivery were referred to La Timone Hospital, Marseille, France. Women were consecutively included between 2000 and 2015. VTE characteristics and biological parameters were collected upon inclusion. During the 2016-2019 period, patients were recontacted to gather information on postinclusion VTE. A weighted Cox model, adapted to the study's ambispective design, was used to analyze pre- and postinclusion VTE recurrences.

RESULTS

After quality controls, 583 women were analyzed. The incidence of recurrent VTE was 2.4% person-years. The cumulative risk of VTE recurrence was 38% (n = 221), with a median follow-up of 31 years (95% CI: 27-35); 6%, 13%, 17%, and 30% at 2, 5, 10, and 30 years respectively. Pulmonary embolism at first event was associated with a 2-fold increased risk of pulmonary embolism at recurrence compared with isolated deep venous thrombosis (DVT, hazard ratio [HR]: 2.63; 95% CI: 1.44-4.82). Risk factors significantly associated with recurrence were interrupted pregnancies (HR: 1.85; 95% CI: 1.18-2.90), lower limb DVT (HR: 2.95; 95% CI: 1.16-7.49), and AB blood group (HR: 1.71; 95% CI: 1.06-2.77).

CONCLUSION

Although the recurrence risk is low within the first 10 years after a pregnancy-associated VTE, one-third of patients experienced a new event over a 30-year period. Interrupted pregnancies, lower limb DVT, and AB blood group were associated with higher risk of recurrence.

Associations of coagulation parameters and thrombin generation potential with the incidence of type 2 diabetes: mediating role of glycoprotein acetylation

Hypercoagulability is characterized by abnormal elevations of coagulation factor levels and increased thrombin generation potential. Prior studies demonstrated links between impaired glucose metabolism, endothelial dysfunction, and hypercoagulability. However, the associations between hypercoagulability and incident type 2 diabetes as well as its underlying mechanism remain unclear. We aimed to assess the associations between coagulation parameters including coagulation factor (F) VIII, FIX, FXI, fibrinogen, thrombin generation potential (lag time, endogenous thrombin potential [ETP], peak, time-to-peak, velocity) and incident type 2 diabetes, and to study the underlying mechanism by examining the mediating role of glycoprotein acetylation (GlycA). In the Netherlands Epidemiology of Obesity study, we applied a Cox Proportional-Hazards Model in 5718 participants after adjustment for confounders. We further conducted a mediation analysis investigating the mediation effect of GlycA on the observed associations. During a median follow-up of 6.7 years, 281 incident type 2 diabetes diagnoses were reported. Compared with the lowest quartile, hazard ratio (95% confidence interval) of the highest quartile was 2.47 (1.48-4.14) for FIX, 1.37 (0.85-2.20) for FVIII, 1.11 (0.76-1.63) for FXI, 0.98 (0.65-1.48) for fibrinogen, 1.56 (1.07-2.28) for ETP, 1.84 (1.23-2.74) for peak, 1.59 (1.08-2.33) for velocity, 0.92 (0.62-1.38) for lag time, and 1.21 (0.86-1.70) for time-to-peak. GlycA mediated only a small proportion of all observed associations. In conclusion, elevated levels of coagulation factor and thrombin generation potential are associated with incident type 2 diabetes, suggesting the involvement of hypercoagulability in the pathogenesis of type 2 diabetes.

SMIM1 absence is associated with reduced energy expenditure and excess weight

BACKGROUND

Obesity rates have nearly tripled in the past 50 years, and by 2030 more than 1 billion individuals worldwide are projected to be obese. This creates a significant economic strain due to the associated non-communicable diseases. The root cause is an energy expenditure imbalance, owing to an interplay of lifestyle, environmental, and genetic factors. Obesity has a polygenic genetic architecture; however, single genetic variants with large effect size are etiological in a minority of cases. These variants allowed the discovery of novel genes and biology relevant to weight regulation and ultimately led to the development of novel specific treatments.

METHODS

We used a case-control approach to determine metabolic differences between individuals homozygous for a loss-of-function genetic variant in the small integral membrane protein 1 (SMIM1) and the general population, leveraging data from five cohorts. Metabolic characterization of SMIM1-/- individuals was performed using plasma biochemistry, calorimetric chamber, and DXA scan.

FINDINGS

We found that individuals homozygous for a loss-of-function genetic variant in SMIM1 gene, underlying the blood group Vel, display excess body weight, dyslipidemia, altered leptin to adiponectin ratio, increased liver enzymes, and lower thyroid hormone levels. This was accompanied by a reduction in resting energy expenditure.

CONCLUSION

This research identified a novel genetic predisposition to being overweight or obese. It highlights the need to investigate the genetic causes of obesity to select the most appropriate treatment given the large cost disparity between them.

FUNDING

This work was funded by the National Institute of Health Research, British Heart Foundation, and NHS Blood and Transplant.

A Cross-Sectional Study of the A1 Phenotype in the Colombian Caribbean: A Shadow Behind Pulmonary Embolism

INTRODUCTION

Venous thromboembolic disease (VTE) is an episodic condition of multifactorial origin, commonly manifesting as deep vein thrombosis (DVT) and pulmonary embolism (PE). VTE is a major cause of morbidity and mortality. As an acute condition, it has the potential for recurrence and is associated with major consequences; this disease poses significant challenges to the healthcare system. VTE is a widespread concern in developed and developing countries; therefore, it is not limited to specific regions or populations.

OBJECTIVES

To evaluate the risk factors associated with unprovoked PE in patients in a hospital center in Sincelejo, Colombia.

METHODS

This is an observational, analytical cross-sectional study utilizing retrospective data. From 2010 to 2023, we reviewed 126 medical records of patients who experienced their first unprovoked VTE events and met the inclusion criteria. We performed data analysis using R software version 3.5.1.

RESULTS

Of the patients, 36.5% (n = 46) were women; 63.5% (n = 80) were men, with a mean age of 62.22 years (SD = 10.62). About 53% of women presented with PE, compared to 47% of men. The coagulation factor VIII acted as a PE risk factor (p = 0.098). The best model to predict PE development obtained an Akaike information criterion (AIC) of 176.67, indicating that the A1 positive phenotype is the risk factor with the highest prediction for PE occurrence.

CONCLUSIONS

High levels of coagulation factor VIII and an A1-positive phenotype are risk factors that may increase PE development. These findings suggest the need for preventive strategies in this risk setting to reduce the incidence and recurrence of PE.

Thrombosis Rates and Genetic Thrombophilia Risk Among Patients With Advanced Germ Cell Tumors Treated With Chemotherapy

INTRODUCTION

Men with advanced germ cell tumors (GCT) treated with chemotherapy are at high risk of venous thromboembolism (VTE). Predictors of VTE may identify patients who would benefit from prophylactic anticoagulation.

PATIENTS AND METHODS

Men with advanced GCT (Stage IS, II, III) treated with chemotherapy were identified at 2 centers. High genomic risk was defined from a 5 single nucleotide polymorphism (SNP) germline panel. Logistic regression was used to evaluate the impact of genomic risk on VTE within 6 months of chemotherapy initiation. Orthogonal Projection to Latent Structures Discriminant Analysis (OPLS-DA) was used to build models to predict VTE based on clinical variables and an 86 SNP panel.

RESULTS

This 123-patient cohort experienced a VTE rate of 26% with an incidence of high genomic risk of 21%. Men with high genomic risk did not have a significantly higher VTE rate (31%, 8/26) than men with low genomic risk (25%, 24/97), unadjusted OR 1.4 (95% CI 0.5-3.5, P = .54). Incorporation of clinical variables (Khorana score, N3 status and elevated LDH) resulted in adjusted OR 2.1 (95% CI 0.7-6.5, P = .18). A combined model using clinical variables and 86 SNPs performed similarly (AUC 0.77) compared to clinical variables alone (AUC 0.72).

CONCLUSIONS

A previously established 5-SNP panel was not associated with VTE among patients with GCT receiving chemotherapy. However, multivariable models based on clinical variables alone warrant further validation to inform prophylactic anticoagulation strategies.

Association between ABO genotypes and risk of dementia and neuroimaging markers: roles of sex and APOE status

Background

Whether the relationships between ABO blood genotypes (AA, AO, BB, BO, AB, and OO) and dementia are modified by gender and APOE status has been unclear.

Methods

We used data from the UK Biobank, a population-based cohort study of 487,425 individuals. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CI) between ABO genotypes and risk of dementia. Multivariable linear regression models were used to estimate the relationship between ABO genotypes and MRI-based brain indices.

Results

Overall, 487,425 participants were included at baseline. After 34 million person-years follow up, 7,548 patients developed all-cause dementia. Before stratifying by sex and APOE status, compared to OO genotype, BB genotype was associated with increased risk of all-cause dementia (1.36, 1.03-1.80) and other types dementia (1.65, 1.20-2.28). After stratifying by sex, only in males, BB genotype was associated with higher risk of all-cause dementia (1.44, 1.02-2.09) and other types of dementia (1.95, 1.30-2.93). AB genotype in males was also associated with increased AD (1.34, 1.04-1.72). After further stratifying by APOE e4 status, BB genotype with two APOE e4 alleles showed even stronger association with all-cause dementia 4.29 (1.57, 11.72) and other types dementia (5.49, 1.70-17.69) in males. Also in males, AA genotype with one APOE e4 was associated with increased risks of all-cause dementia (1.27, 1.04-1.55), AD (1.45, 1.09-1.94) and other types dementia (1.40, 1.08-1.81). Linear regression models showed that in both sexes with APOE e4, AA genotype was associated with reduced total grey matter volume.

Conclusion

Sex and APOE e4 carrier status modified the association between ABO genotypes and risk of dementia. In males, BB genotype was consistently associated with increased risk of dementia, especially in those with two APOE e4 alleles. Also, in males with one APOE e4, AA genotype might be linked to higher risk of dementia.

Reassessing the Risk of Venous Thromboembolism (VTE) Events in Women

This research aims to reassess women's risk of venous thromboembolism (VTE) events. We conducted an in-depth analysis of the environmental risk factors associated with VTE and their interactions with gender while also exploring the genetic underpinnings of the disease. VTE is identified as a multifactorial condition influenced by a combination of genetic, non-predisposing, and predisposing environmental factors. We further investigated the genetic basis of VTE, focusing on the identification and analysis of risk loci, as well as gene interaction networks and genetic analyses, which offer significant insights into the pathogenesis of VTE. Recognizing the critical role of gender in assessing VTE risk and developing prevention strategies, this research underscores the necessity of adopting an integrated perspective that accounts for individual vulnerabilities at both genetic and environmental levels to formulate effective preventive measures.

ABO blood types may affect transient neurological events after surgical revascularization in patients with moyamoya disease: a retrospective single center study

BACKGROUND

Moyamoya disease (MMD) is a cerebrovascular disease with unknown cause. Patients with MMD disease usually experience transient neurological events (TNEs) after revascularization surgery. This retrospective single-center study was aimed to explore the risk factors of postoperative TNEs after surgical revascularization in patients with MMD.

METHODS

We selected 324 patients who underwent surgical revascularization between January 2017 and September 2022 in our center. The perioperative characteristics of the patients were recorded and the outcome was TNEs after surgery. An analysis of risk factors contributing to postoperative TNEs by using logistic regression model.

RESULTS

Three hundred twelve patients were enrolled, and the incidence of postoperative TNEs was 34% in our study. Males were more likely to suffer from postoperative TNEs (OR = 2.344, p = 0.002). Preoperative ischemic presentation (OR = 1.849, p = 0.048) and intraoperative hypotension (OR = 2.332, p = 0.002) were associated with postoperative TNEs. Compared to patients with blood type O, patients with blood type A (OR = 2.325, p = 0.028), B (OR = 2.239, p = 0.027) and AB (OR = 2.938, p = 0.019) had a significantly higher incidence of postoperative TNEs. A risk prediction model for postoperative TNEs was established, and the established risk prediction area under the receiver operating characteristic curve (ROC) of the model was 0.741.

CONCLUSIONS

Males, preoperative ischemic presentation and intraoperative hypotension were associated with postoperative TNEs. We also found a possible link between postoperative TNEs and ABO blood types after surgical revascularization for moyamoya patients.

Associations of multiple genetic variations with plasma levels of Von Willebrand Factor and clinical phenotype in Iranian patients with Von Willebrand disease type 1

BACKGROUND

Genetic variations influence the Von Willebrand Factor plasma level and function. This study aims to evaluate the frequency and clinical phenotype effects of eight single nucleotide polymorphism candidates in four genes (VWF, STXBP5, CLEC4M, and ABO) in Iranian patients with VWD type 1.

METHOD

The study recruited 50 patients with VWD type 1 and 100 healthy individuals. The demographic data from all participants were collected, and the High-Resolution Melting technique was used to determine the frequency of specific single nucleotide polymorphisms. Bleeding scores were also obtained from all patients to assess how these genetic variations might affect the severity of their bleeding symptoms.

RESULTS

The study found notable variations in the occurrence of certain SNPs (rs7853989 and rs8176743 for ABO gene and rs1063856 and rs1063857 for VWF gene) between the control group and the patients. Additionally, the study discovered that two SNPs (rs868875 for CLEC4M gene and rs9390459 for STXBP5 gene) were significantly linked to the severity of bleeding, and two others (rs868875 for CLEC4M gene and rs8176746 for ABO gene) were associated with reduced levels of VWF antigen in the patients.

CONCLUSION

According to this study, the above-selected SNPs can cause variations in VWF plasma levels in patients with VWD type 1. Furthermore, the effects of SNPs on bleeding phenotype prove the role of these SNPs in the severity of bleeding manifestations in patients.

Evaluation of Single Nucleotide Variants in Intron 1 of the ABO Gene as Diagnostic Markers for the A1 Blood Group

Introduction

The molecular diagnosis of the A1 blood group is based on the exclusion of ABO gene variants causing blood groups A2, B, or O. A specific genetic marker for the A1 blood group is still missing. Recently, long-read ABO sequencing revealed four sequence variations in intron 1 as promising markers for the ABO*A1 allele. Here, we evaluated the diagnostic values of the 4 variants in blood donors with regular and weak A phenotypes and genotypes.

Methods

ABO phenotype data (A, B, AB, or O) were taken from the blood donor files. The ABO genotypes (low resolution) were known from a previous study and included the variants c.261delG, c.802G>A, c.803G>C, and c.1061delC. ABO variant alleles (ABO*AW.06,*AW.08,*AW.09,*AW.13, *AW.30, and *A3.02) were identified in weak A donors by sequencing the ABO exons before. For genotyping of the ABO intron 1 variants rs532436, rs1554760445, rs507666, and rs2519093, we applied TaqMan assays with endpoint fluorescence detection according to a standard protocol. Genotypes of the variants were compared with the ABO phenotype and genotype. Evaluation of diagnostic performance included sensitivity, specificity, positive (PPV), and negative predictive value (NPV).

Results

In 1,330 blood donors with regular ABO phenotypes and genotypes, the intron 1 variants were significantly associated with the proposed A1 blood group. In 15 donors, we found discrepancies to the genotype of at least one of the 4 variants. For the diagnosis of the ABO*A1 allele, the variants showed 98.79-99.48% sensitivity, 99.66-99.81% specificity, 98.80-99.31% PPV, and 99.66-99.86% NPV. Regarding the A phenotype, the diagnostic values were 99.02-99.41% sensitivity, 99.63-99.76% specificity, 99.41-99.61% PPV, and 99.39-99.63% NPV. The *A1 marker allele of all intron 1 variants was also associated with the *AW.06, *AW.13, and *AW.30 variants. Samples with *AW.08, *AW.09, and *A3.02 variants lacked this association.

Conclusion

The ABO intron 1 variants revealed significant association with the ABO*A1 allele and the A phenotype. However, the intron 1 genotype does not exclude variant alleles causing weak A phenotypes. With the introduction of reliable tag, single nucleotide variants for the A1, A2, B, and O blood groups and the genotyping instead of phenotyping of the ABO blood group are getting more feasible on a routine basis.

Haplotype sequence collection of ABO blood group alleles by long-read sequencing reveals putative A1-diagnostic variants

In the era of blood group genomics, reference collections of complete and fully resolved blood group gene alleles have gained high importance. For most blood groups, however, such collections are currently lacking, as resolving full-length gene sequences as haplotypes (ie, separated maternal/paternal origin) remains exceedingly difficult with both Sanger and short-read next-generation sequencing. Using the latest third-generation long-read sequencing, we generated a collection of fully resolved sequences for all 6 main ABO allele groups: ABO∗A1/A2/B/O.01.01/O.01.02/O.02. We selected 77 samples from an ABO genotype data set (n = 25 200) of serologically typed Swiss blood donors. The entire ABO gene was amplified in 2 overlapping long-range polymerase chain reactions (covering ∼23.6 kb) and sequenced by long-read Oxford Nanopore sequencing. For quality validation, 2 samples per ABO group were resequenced using Illumina and Pacific Biosciences technology. All 154 full-length ABO sequences were resolved as haplotypes. We observed novel, distinct sequence patterns for each ABO group. Most genetic diversity was found between, not within, ABO groups. Phylogenetic tree and haplotype network analyses highlighted distinct clades of each ABO group. Strikingly, our data uncovered 4 genetic variants putatively specific for ABO∗A1, for which direct diagnostic targets are currently lacking. We validated A1-diagnostic potential using whole-genome data (n = 4872) of a multiethnic cohort. Overall, our sequencing strategy proved powerful for producing high-quality ABO haplotypes and holds promise for generating similar collections for other blood groups. The publicly available collection of 154 haplotypes will serve as a valuable resource for molecular analyses of ABO, as well as studies about the function and evolutionary history of ABO.

ABO Blood Groups in Systemic Sclerosis: Distribution and Association with This Disease's Characteristics

Systemic sclerosis (SSc) is an autoimmune disease associated with endothelial activation and fibrosis. Non-O blood group patients carry an increased risk of thrombosis, fibrosis and autoimmune diseases. The aim of our work was to evaluate the distribution of ABO groups in SSc patients and their association with the disease's characteristics. ABO groups were determined in 504 SSc patients (with 131 completed by a genotypic analysis). The distribution of ABO groups and their diplotypes in SSc patients was comparable to that of the general population, except for haplotypes O1 and B (65.6% vs. 61.6% and 8.8% vs. 5.8% in SSc patients vs. the general population, respectively, p = 0.01). The frequency of interstitial lung disease, pulmonary hypertension, calcinosis, digital ulcers, digestive diseases and venous thrombosis, and the Medsger score, were higher in non-O than in O-SSc patients, although they did not display statistical significance. Patients in the non-O group had higher levels of inflammation and endothelial activation biomarkers. In conclusion, the ABO blood group distribution of SSc patients did not differ significantly from that of the general population, but non-O blood groups were associated with inflammation and endothelial activation, and with a non-significant higher frequency of pulmonary and vascular complications in SSc.

Contribution of Common Genetic Variants to Risk of Early-Onset Ischemic Stroke

BACKGROUND AND OBJECTIVES

Current genome-wide association studies of ischemic stroke have focused primarily on late-onset disease. As a complement to these studies, we sought to identify the contribution of common genetic variants to risk of early-onset ischemic stroke.

METHODS

We performed a meta-analysis of genome-wide association studies of early-onset stroke (EOS), ages 18-59 years, using individual-level data or summary statistics in 16,730 cases and 599,237 nonstroke controls obtained across 48 different studies. We further compared effect sizes at associated loci between EOS and late-onset stroke (LOS) and compared polygenic risk scores (PRS) for venous thromboembolism (VTE) between EOS and LOS.

RESULTS

We observed genome-wide significant associations of EOS with 2 variants in ABO, a known stroke locus. These variants tag blood subgroups O1 and A1, and the effect sizes of both variants were significantly larger in EOS compared with LOS. The odds ratio (OR) for rs529565, tagging O1, was 0.88 (95% confidence interval [CI]: 0.85-0.91) in EOS vs 0.96 (95% CI: 0.92-1.00) in LOS, and the OR for rs635634, tagging A1, was 1.16 (1.11-1.21) for EOS vs 1.05 (0.99-1.11) in LOS; p-values for interaction = 0.001 and 0.005, respectively. Using PRSs, we observed that greater genetic risk for VTE, another prothrombotic condition, was more strongly associated with EOS compared with LOS (p = 0.008).

DISCUSSION

The ABO locus, genetically predicted blood group A, and higher genetic propensity for venous thrombosis are more strongly associated with EOS than with LOS, supporting a stronger role of prothrombotic factors in EOS.

[Relationship Between ABO Blood Group and Pregnancy Complications]

ABO blood group system is the most commonly used blood group classification system in clinic practice. The relevant antigens, A, B and H determinants, are complex carbohydrate molecules that are expressed in red blood cells and other cell lines and tissues. These antigens are determined by the ABO locus located on chromosome 9 (9q34.1-q34.2). ABO blood group is associated with the development of many human diseases, e.g., cardiovascular diseases, infectious diseases, and tumors. The relationship between the ABO blood group of pregnant women and various pregnancy complications, including preeclampsia (PE) and the related diseases, pregnancy associated venous thromboembolism (PA-VTE), gestational diabetes mellitus (GDM), and postpartum hemorrhage (PPH), have become the focus of obstetricians' recent research interest. Herein, we reviewed the relationship between ABO blood group and these pregnancy complications, and found that most of the reported findings supported the following views: 1) Blood type O is a protective factor for PE, while blood type AB increases the risk of PE; 2) blood types other than O are more prone to PA-VTE than blood type O; 3) blood type O or blood type AB may be related to the pathogenesis of GDM; 4) women of blood type O are at higher risks for PPH than those of other blood types. More in-depth epidemiological and genetic studies are needed to confirm these findings in the future. These findings can provide new ideas for researching into the pathogenesis of obstetric diseases and form the theoretical basis for obstetricians to prevent and treat related diseases.

The Roles of Gut Microbiome and Plasma Metabolites in the Associations between ABO Blood Groups and Insulin Homeostasis: The Microbiome and Insulin Longitudinal Evaluation Study (MILES)

Non-O blood groups are associated with decreased insulin sensitivity and risk of type 2 diabetes. A recent study pinpointed the associations between ABO blood groups and gut microbiome, which may serve as potential mediators for the observed increased disease risks. We aimed to characterize associations between ABO haplotypes and insulin-related traits as well as potential mediating pathways. We assessed insulin homeostasis in African Americans (AAs; n = 109) and non-Hispanic whites (n = 210) from the Microbiome and Insulin Longitudinal Evaluation Study. The ABO haplotype was determined by six SNPs located in the ABO gene. Based on prior knowledge, we included 21 gut bacteria and 13 plasma metabolites for mediation analysis. In the white study cohort (60 ± 9 years, 42% male), compared to the O1 haplotype, A1 was associated with a higher Matsuda insulin sensitivity index, while a lower relative abundance of Bacteroides massiliensis and lactate levels. Lactate was a likely mediator of this association but not Bacteroides massiliensis. In the AAs group (57 ± 8 years, 33% male), we found no association between any haplotype and insulin-related traits. In conclusion, the A1 haplotype may promote healthy insulin sensitivity in non-Hispanic whites and lactate likely play a role in this process but not selected gut bacteria.

ABO O blood group as a risk factor for platelet reactivity in heparin-induced thrombocytopenia

Heparin-induced thrombocytopenia (HIT) is an unpredictable, potentially catastrophic adverse effect resulting from an immune response to platelet factor 4 (PF4)/heparin complexes. We performed a genome-wide association study (GWAS) with positive functional assay as the outcome in a large discovery cohort of patients divided into 3 groups: (1) functional assay-positive cases (n = 1269), (2) antibody-positive (functional assay-negative) controls (n = 1131), and (3) antibody-negative controls (n = 1766). Significant associations (α = 5 × 10-8) were investigated in a replication cohort (α = 0.05) of functional assay-confirmed HIT cases (n = 177), antibody-positive (function assay-negative) controls (n = 258), and antibody-negative controls (n = 351). We observed a strong association for positive functional assay with increasing PF4/heparin immunoglobulin-G (IgG) level (odds ratio [OR], 16.53; 95% confidence interval [CI], 13.83-19.74; P = 1.51 × 10-209) and female sex (OR, 1.15; 95% CI, 1.01-1.32; P = .034). The rs8176719 C insertion variant in ABO was significantly associated with positive functional assay status in the discovery cohort (frequency = 0.41; OR, 0.751; 95% CI, 0.682-0.828; P = 7.80 × 10-9) and in the replication cohort (OR, 0.467; 95% CI, 0.228-0.954; P = .0367). The rs8176719 C insertion, which encodes all non-O blood group alleles, had a protective effect, indicating that the rs8176719 C deletion and the O blood group were risk factors for HIT (O blood group OR, 1.42; 95% CI, 1.26-1.61; P = 3.09 × 10-8). Meta-analyses indicated that the ABO association was independent of PF4/heparin IgG levels and was stronger when functional assay-positive cases were compared with antibody-positive (functional assay-negative) controls than with antibody-negative controls. Sequencing and fine-mapping of ABO demonstrated that rs8176719 was the causal single nucleotide polymorphism (SNP). Our results clarify the biology underlying HIT pathogenesis with ramifications for prediction and may have important implications for related conditions, such as vaccine-induced thrombotic thrombocytopenia.

The risk variant rs11836367 contributes to breast cancer onset and metastasis by attenuating Wnt signaling via regulating NTN4 expression

Most genome-wide association study (GWAS)-identified breast cancer-associated causal variants remain uncharacterized. To provide a framework of understanding GWAS-identified variants to function, we performed a comprehensive study of noncoding regulatory variants at the NTN4 locus (12q22) and NTN4 gene in breast cancer etiology. We find that rs11836367 is the more likely causal variant, disrupting enhancer activity in both enhancer reporter assays and endogenous genome editing experiments. The protective T allele of rs11837367 increases the binding of GATA3 to the distal enhancer and up-regulates NTN4 expression. In addition, we demonstrate that loss of NTN4 gene in mice leads to tumor earlier onset, progression, and metastasis. We discover that NTN4, as a tumor suppressor, can attenuate the Wnt signaling pathway by directly binding to Wnt ligands. Our findings bridge the gaps among breast cancer-associated single-nucleotide polymorphisms, transcriptional regulation of NTN4, and breast cancer biology, which provides previously unidentified insights into breast cancer prediction and prevention.

A year of Covid-19 GWAS results from the GRASP portal reveals potential genetic risk factors

Host genetic variants influence the susceptibility and severity of several infectious diseases, and the discovery of genetic associations with Covid-19 phenotypes could help developing new therapeutic strategies to reduce its burden. Between May 2020 and June 2021, we used Covid-19 data released periodically by UK Biobank and performed 65 Genome-Wide Association Studies (GWAS) in up to 18 releases of Covid-19 susceptibility (N=18,481 cases in June 2021), hospitalization (N=3,260), severe outcomes (N=1,244) and death (N=1,104), stratified by sex and ancestry. In coherence with previous studies, we observed 2 independent signals at the chr3p21.31 locus (rs73062389-A, OR=1.21, P=4.26×10^-15 and rs71325088-C, OR=1.62, P=2.25×10^-9) modulating susceptibility and severity, respectively, and a signal influencing susceptibility at the ABO locus (rs9411378-A, OR=1.10, P=3.30×10^-12), suggesting an increased risk of infection in non-O blood groups carriers. Additional signals at the APOE (associated with severity and death) LRMDA (susceptibility in non-European) and chr2q32.3 (susceptibility in women) loci were also identified but did not replicate in independent datasets. We then devised an approach to extract variants suggestively associated (P<10^-5) exhibiting an increase in significance over time. When applied to the susceptibility, hospitalization and severity analyses, this approach revealed the known RPL24, DPP9, and MAPT loci, respectively, amongst hundreds of other signals. These results, freely available on the GRASP portal, provide insights on the genetic mechanisms involved in Covid-19 phenotypes.

The risk of venous thromboembolism attributed to established prothrombotic genotypes

BACKGROUND

The proportion of venous thromboembolism (VTE) events that can be attributed to established prothrombotic genotypes has been scarcely investigated in the general population. We aimed to estimate the proportion of VTEs in the population that could be attributed to established prothrombotic genotypes using a population-based case-cohort.

METHODS

Cases with incident VTE (n=1,493) and a randomly sampled sub-cohort (n=13,069) were derived from the Tromsø Study (1994-2012) and the Nord-Trøndelag Health (HUNT) Study (1995-2008). DNA-samples were genotyped for 17 single nucleotide polymorphism (SNPs) associated with VTE. Hazard ratios with 95% confidence intervals (CIs) were estimated in Cox regression models. Population attributable fraction (PAF) with 95% bias-corrected CIs (based on 10,000 bootstrap samples) were estimated using a cumulative model where SNPs significantly associated with VTE were added one-by-one in ranked order of the individual PAFs.

RESULTS

Six SNPs were significantly associated with VTE (rs1799963 [Prothrombin], rs2066865 [FGG], rs6025 [FV Leiden], rs2289252 [F11], rs2036914 [F11] and rs8176719 [ABO]. The cumulative PAF for the six-SNP model was 45.3% (95% CI 19.7-71.6) for total VTE and 61.7% (95% CI 19.6-89.3) for unprovoked VTE. The PAF for prothrombotic genotypes was higher for DVT (52.9%) than for PE (33.8%), and higher for those aged <70 years (66.1%) than for those aged ≥70 years (24.9%).

CONCLUSIONS

Our findings suggest that 45-62% of all VTE events in the population can be attributed to known prothrombotic genotypes. The PAF of established prothrombotic genotypes was higher in DVT than in PE, and higher in the young than in the elderly.

Characterization of the human ABO genotypes and their association to common inflammatory and cardiovascular diseases in the UK Biobank

The ABO gene contains three major alleles that encodes different antigens; A, B, and O, which determine an individual's blood group. Previous studies have primarily focused on identifying associations between ABO blood groups and diseases risk. Here, we sought to test for association between ABO genotypes (OO, OA, AA; OB, BB, and AB) and a large set of common inflammatory and cardiovascular diseases in UK Biobank as well as disease-related protein biomarkers in NSPHS. We first tested for association by conducting a likelihood ratio test, testing whether ABO contributed significantly to the risk for 24 diseases, and 438 plasma proteins. For phenotypes with FDR < 0.05, we tested for pair-wise differences between genetically determined ABO genotypes using logistic or linear regression. Our study confirmed previous findings of a strong association between ABO and cardiovascular disease, identified associations for both type 1 and type 2 diabetes, and provide additional evidence of significant differences between heterozygous and homozygous allele carriers for pulmonary embolism, deep vein thrombosis, but also for von Willebrand factor levels. Furthermore, the results indicated an additive effect between genotypes, even between the two most common A subgroups, A1 and A2. Additionally, we found that ABO contributed significantly to 39 plasma proteins, of which 23 have never been linked to the ABO locus before. These results show the need of incorporating ABO genotype information in the consultation and management of patients at risk, rather than classifying patients into blood groups.