# The Absence of Association Between NQO1 rs1800566 Polymorphism and Promoter Methylation With the Risk of Preeclampsia

## TL;DR

This study found no link between a specific NQO1 gene variant or its methylation and preeclampsia risk, but confirmed oxidative stress in affected patients.

## Contribution

The study is the first to report no association between NQO1 rs1800566 polymorphism/promoter methylation and preeclampsia risk.

## Key findings

- Preeclamptic patients showed signs of oxidative stress, including elevated MDA and GPx activity.
- No association was found between NQO1 rs1800566 polymorphism or promoter methylation and preeclampsia risk.
- Levels of TAC, Zn, and Se were reduced in preeclamptic patients compared to controls.

## Abstract

Oxidative stress plays a crucial role in the pathogenesis of preeclampsia. Given that the NADPH quinone oxidoreductase 1 (NQO1) is an important enzyme in the antioxidant system, this study aimed to investigate the relationship between the NQO1 rs1800566 polymorphism, NQO1 promoter methylation, and oxidative stress with the risk of preeclampsia.

This case-control study analyzed 170 women, including preeclampsia patients and healthy pregnant women. To investigate the NQO1 rs1800566 variants, the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method was used. Promoter methylation analysis in 96 of these samples was conducted using quantitative methylation-specific PCR (qMSP) method. Glutathione peroxidase (GPx) and superoxide dismutase (SOD) activity, along with zinc (Zn), copper (Cu), selenium (Se), malondialdehyde (MDA), and total antioxidant capacity (TAC) levels were measured using chemical methods.

We found reduced levels of TAC, Zn, and Se, and also the SOD activity in patients than controls. However, the MDA and Cu levels, and the GPx activity increased in preeclamptic patients. No association was identified between the NQO1 rs1800566 variants or NQO1 promoter methylation with the risk of preeclampsia.

It seems the NQO1 rs1800566 and the promoter methylation of NQO1 gene are not involved in the risk of preeclampsia. However, our findings indicate the presence of oxidative stress in preeclamptic patients.