Management of pregnancy in women with factor VII deficiency: A case series.

INTRODUCTION: Inherited factor VII deficiency is the most common autosomal recessive inherited bleeding disorder, with an estimated incidence of one per 500 000 cases in the general population. Bleeding manifestations correlate poorly with circulating FVII levels. During pregnancy, increases in FVII levels can occur in women with mild-moderate FVII deficiencies but not in those with severe deficiency. AIM: We present five pregnant patients with FVII deficiency and describe the management during their pregnancies and peripartum periods. METHODS: Retrospective analysis of six pregnancies in five women with FVII deficiency followed during pregnancy and delivery at an academic medical centre between January 2013 and December 2019. RESULTS: Of the five patients, two had severe, one with moderate and two with mild FVII deficiency. Early postpartum haemorrhage (PPH) occurred in two patients. One of the two severe FVII-deficient patients had PPH with a laceration at delivery despite replacement therapy with recombinant factor VII. The other PPH occurred in a patient with mild FVII deficiency who delivered twins by caesarean section under general anaesthesia. Neuraxial anaesthesia was utilized in only one woman with mild deficiency whose FVII level normalized at the end of the pregnancy. CONCLUSIONS: Management of delivery for women with FVII deficiency should be addressed on a case-by-case basis at centres with expertise in rare bleeding disorders, maternal foetal medicine and obstetric anaesthesiology. These management discussions should factor the patient's bleeding history, third trimester PT, FVII level, multiple gestation and mode of delivery.

Genome-Wide Association Transethnic Meta-Analyses Identifies Novel Associations Regulating Coagulation Factor VIII and von Willebrand Factor Plasma Levels.

BACKGROUND: Factor VIII (FVIII) and its carrier protein von Willebrand factor (VWF) are associated with risk of arterial and venous thrombosis and with hemorrhagic disorders. We aimed to identify and functionally test novel genetic associations regulating plasma FVIII and VWF. METHODS: We meta-analyzed genome-wide association results from 46 354 individuals of European, African, East Asian, and Hispanic ancestry. All studies performed linear regression analysis using an additive genetic model and associated ≈35 million imputed variants with natural log-transformed phenotype levels. In vitro gene silencing in cultured endothelial cells was performed for candidate genes to provide additional evidence on association and function. Two-sample Mendelian randomization analyses were applied to test the causal role of FVIII and VWF plasma levels on the risk of arterial and venous thrombotic events. RESULTS: We identified 13 novel genome-wide significant ( P≤2.5×10-8) associations, 7 with FVIII levels ( FCHO2/TMEM171/TNPO1, HLA, SOX17/RP1, LINC00583/NFIB, RAB5C-KAT2A, RPL3/TAB1/SYNGR1, and ARSA) and 11 with VWF levels ( PDHB/PXK/KCTD6, SLC39A8, FCHO2/TMEM171/TNPO1, HLA, GIMAP7/GIMAP4, OR13C5/NIPSNAP, DAB2IP, C2CD4B, RAB5C-KAT2A, TAB1/SYNGR1, and ARSA), beyond 10 previously reported associations with these phenotypes. Functional validation provided further evidence of association for all loci on VWF except ARSA and DAB2IP. Mendelian randomization suggested causal effects of plasma FVIII activity levels on venous thrombosis and coronary artery disease risk and plasma VWF levels on ischemic stroke risk. CONCLUSIONS: The meta-analysis identified 13 novel genetic loci regulating FVIII and VWF plasma levels, 10 of which we validated functionally. We provide some evidence for a causal role of these proteins in thrombotic events.

The prevalence of inherited thrombophilic polymorphisms in an asymptomatic Australian antenatal population.

AIM: Inherited thrombophilic polymorphisms have been linked to pregnancy-related thromboembolism and other adverse pregnancy outcomes. As there are limited data on the prevalence of these polymorphisms in Australian populations, we aimed to assess this in an antenatal population. METHODS: Healthy nulliparous women (n = 2031) were recruited to this study. The women had no past or family history of venous thromboembolism. Women were excluded if they or a family member was known to be a carrier of any thrombophilic marker. Genotyping from venous blood for the factor V Leiden, prothrombin 20210A, MTHFR 677 and 1298 and thrombomodulin C1418T polymorphisms was undertaken. RESULTS: Key findings were that 107 of 2019 (5.30, 95% confidence interval 4.36-6.37%) women tested were heterozygous carriers of factor V Leiden and one was homozygous (0.05, 0-0.27%); 2.43% of women were heterozygous carriers of the prothrombin gene mutation (1.80-3.20%) while no women were homozygous for this mutation; 11.62% (10.22-13.02%) and 9.98% (8.67-11.29%) were homozygous for the MTHFR 677 and 1298 polymorphisms, respectively, and 3.43% (2.63-4.22%) of women were homozygous for the thrombomodulin polymorphism. CONCLUSIONS: The prevalence of these polymorphisms is consistent with previously published data in Caucasian populations. These data will provide the basis for further assessment of the relationship between poor pregnancy outcome and these inherited thrombophilic polymorphisms in an asymptomatic antenatal population.

Ethnic differences in the prevalence of inherited thrombophilic polymorphisms in an asymptomatic Australian prenatal population.

Differences in the prevalence of thrombophilias in different ethnic populations have been demonstrated. Because the Australian population includes many different ethnic groups, we sought to assess the effect of ethnicity in our Australian prenatal population on the prevalence of thrombophilic polymorphisms. Asymptomatic, nulliparous women (n = 1,129) recruited for a large prospective study were included in this analysis. These women had no personal or family history of venous thromboembolism and were not known to be carrying an inherited or acquired thrombophilia. Ethnicity was determined at recruitment, and women were categorized as being of Northern European, Southern European, Middle Eastern, Asian, or Other ethnicity. These women underwent genotyping for the following polymorphisms: factor V Leiden G1691A, prothrombin gene A20210G mutation, methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C, and thrombomodulin C1418T. The factor V Leiden allele was seen significantly more frequently in patients of Middle Eastern background compared to those of Northern European and Asian ethnicity (p < 0.05). The prothrombin gene mutation was seen significantly more frequently in patients of Southern European ethnicity compared to those of Northern European or Asian ethnicity (p < 0.05). The MTHFR C677T allele (mutant) was significantly less common in those of Asian ethnicity compared to patients of Northern European and Southern European ethnicity (p < 0.0005). There were no significant differences seen with the MTHFR A1298C polymorphism. The mutant thrombomodulin allele was seen significantly more frequently in Asian women compared to Northern European, Southern European, or Middle Eastern women (p < 0.005). There are important ethnic differences in the prevalence of thrombophilic polymorphisms in the Australian prenatal population.

The prevalence of inherited thrombophilias in a Caucasian Australian population.

AIMS: To describe the prevalence of four inherited thrombophilias and their combinations for the first time in a large Caucasian Australian population. METHODS: Newborn screening cards of 883 Caucasian babies born in South Australia in 1986-1999 were de-identified and tested for the following inherited thrombophilic polymorphisms: factor V Leiden (G1691A), prothrombin gene mutation (G20210A), methylenetetrahydrofolate reductase gene (MTHFR) C677T and A1298C, as well as compound heterozygosity for the MTHFR polymorphisms. RESULTS: The birth prevalences of heterozygosity and homozygosity for the four thrombophilic polymorphisms were: factor V Leiden 9.5% and 0.7%, prothrombin gene 4.1% and 0.2%, MTHFR C677T 37.3% and 12.4%, and MTHFR A1298C 38.3% and 11.8%, respectively. Compound heterozygosity for MTHFR C677T and A1298C was seen in 16.6% of the population. Overall, 64.2% and 24.5% of the population studied were homozygous and heterozygous, respectively, for at least one of the four polymorphisms studied. CONCLUSION: Inherited thrombophilic polymorphisms are common in the Caucasian Australian population. Knowledge of the background prevalence of these polymorphisms will allow further study of their associations in future disease research.