Abstract Number: PB0697
Meeting: ISTH 2021 Congress
Background: Factor XI deficiency (FXIDef) is an otherwise rare bleeding disorder that commonly affects Ashkenazi and Iraqi Jews; homozygous prevalence is 1:450, and heterozygosity prevalence is 8%. Pregnancy in FXIDef may pose a potential increased bleeding risk during delivery.
Aims: In our Hematology Consultation Service, we reviewed and analyzed genotypes and phenotypes of pregnant women with FXIDef.
Methods: We identified 39 patients with FXIDef evaluated between October 2016 and February 2020. Diagnosis was established on routine genetic screening during pregnancy. Comparisons between FXI Activity levels (FXIAct) at first visit and near term, and between genotypes, were made with two-sample T-test. Anesthetic modalities and routes of delivery were extracted from the record.
Results: In the sample, 61.54% presented mutation c.901T>C, p.F301L (c.901); 28.20% had mutation c.403G>T, p.E135X (c.403); and 10.26% had 4 different mutations. In the c.901 group, 87.5% showed Jewish ancestry, while 72.73% in the c.403 group presented this ancestry. No statistically significant differences in FXIAct at first visit (p=0.43), or at near term (p=0.45), were seen between the commonest mutations. Comparing FXIAct within the same genotype between the first appointment and near term again showed no significant difference. One patient (c.901) received prophylactic intervention before delivery (tranexamic acid). No other patients received hemostatic interventions. Route of delivery did not differ between genotypes. See Table-1 and Figure-2 for further data.
|c.901T>C, p.F301L (n=24)||c403G>T, p.E135X (n=11)|
|Mean Age (years)||33.12 ± 3.94||33.91 ± 3.83|
|Number of homozygous patients (n; %)||1; 4.2%||0; 0%|
|Mean FXI activity on 1st appointment (%) (normal range: 50-150%)||54.92 ± 18.68||68.00 ± 51.69|
|Mean aPTT on 1st appointment (s) (normal range: 24.6- 34.7s)||30.90 ± 3.19||31.85 ± 2.51|
|Mean INR on 1st appointment (normal range: 0.9-1.1)||0.97 ± 0.07||1 ± 0.04|
|Mean FXI activity near term (%) (normal range: 50-150%)||55.26 ± 23.13||50.11 ± 11.13|
|Mean aPTT at birth (s) (normal range: 24.6- 34.7s)||30.04 ± 2.16||30.48 ± 2.54|
|Neuraxial Anesthesia (n; %)||15; 62.5%||5; 45.45%|
|p-Value comparing FXIA on 1st appointment and near term||0.96||0.29|
Conclusions: No significant differences in FXIAct or clinical presentation were noted between genotypes in our series, in which all patients but one were heterozygous. Genotypes correlate with ethnicity, with mutations c.901 and c.403 associated with Jewish ancestry. Comparing our data with other cohorts may allow for broadening of the finding that different genotypes do not affect presentation during pregnancy. Nonetheless, monitoring for FXIDef allows for prophylactic treatment in cases of increased bleeding risk. Therefore, genetic tests are valuable for counseling and diagnostic purposes.
To cite this abstract in AMA style:Sacchi de Camargo Correia G, Rajeeve S, Cytryn L. Factor XI Deficiency in Pregnant Women: A Genotype to Phenotype Correlation and Analysis [abstract]. Res Pract Thromb Haemost. 2021; 5 (Suppl 2). https://abstracts.isth.org/abstract/factor-xi-deficiency-in-pregnant-women-a-genotype-to-phenotype-correlation-and-analysis/. Accessed November 29, 2021.
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