Venous thromboembolism: racial and ethnic influences

Prevalence of Factor V Leiden G1691A and Prothrombin G20210A Gene Mutation Among Pregnant Women: Experience from a Multi-Center Study in Nigeria

Introduction

Inherited thrombophilia and venous thromboembolism (VTE) have been closely linked to adverse pregnancy outcomes such as preeclampsia/eclampsia contributing to increased maternal and perinatal morbidity and mortality. There is, however, little genetic data from Africa including Nigeria that explores the prevalence of common VTE genetic risk markers such as factor V Leiden mutation (FVL G1691A) and prothrombin gene mutation (F2 G20210A) among pregnant women in Nigeria.

Purpose

To determine the prevalence and distribution of FVL G1691A and F2 G20210A in pregnant women in Lagos, Nigeria.

Patients and Methods

This hospital-based cross-sectional pilot study was conducted among pregnant women between 1 July 2019 and 31 August 2020. The genotype of interest was determined through amplification by polymerase chain reaction using G1691A of FV and prothrombin A20210G specific primers. Descriptive data were presented using Stata version 15 (Stata Corp) statistical software.

Results

Of the 400 recruited participants, 397 and 389 samples were successfully processed for FVL G1691A and F2 G20210A mutations, respectively. Three participants had FVL heterozygous mutation; thus, the prevalence of heterozygous mutation of FVL among the study participants was 0.76%, 95% CI: 0.002-0.023%, n=3/397. There was no F2 G20210A mutation detected among the study participants.

Conclusion

This study indicates that screening for factor V Leiden mutation and prothrombin gene mutation in pregnancy might not be of any clinical significance among Nigerian women. However, carrying out a genome-wide associated study is recommended to determine the true impact of these two common inherited thrombophilias in this population.

Venous thromboembolism and ethnicity

Venous thromboembolism (VTE) has long been considered a disease that affects predominantly white populations, a misconception resulting from a paucity of epidemiological data from non-Western countries, and the low incidence of hereditary thrombophilia in those of non-Caucasian background. Over the last decade, interest has grown in this area with the emergence of evidence that VTE is as prevalent, if not more so, in the black population and is also common in Asian groups. Much is still to be learned, as our current knowledge of hereditary thrombophilia and acquired risk factors do not fully explain the risk of VTE in non-Caucasian groups. This review summarises the current understanding of ethnic variation in VTE and highlights the need for further research in this area.