PP004. Study of the methylenetetrahydrofolate reductase and the reduced-folate carrier-1 gene polymorphism in healthy and severe pre-eclamptic patients

Abstract

One-carbon cycle is involved in two essential physiological processes: The synthesis of purins and pyrimidines required for DNA synthesis and repair. The other is the methylation with the methionine cycle. These one-carbon groups are served by the tetrahydrofolate and the S-adenosylmethionine. Deficiencies of the folate, or other abnormalities within the methionine pathway lead to elevated homocysteine levels. These disorders have been implicated in placental diseases. Earlier studies have shown that homocysteine levels are elevated by patients with severe pre-eclampsia than by healthy pregnant normotensive women. Methylenetetrahydrofolate reductase (MTHFR) gene C677T missense mutation has a high frequency by patients with HELLP syndrome and connected with elevated serum homocysteine levels. The reduced-folate carrier (RFC-1) facilitates the internalization of 5-methyltetrahydrofolate from the blood into peripheral cells. The mutation G80A this gene leads to higher plasma folate. Our aim was to identify the polymorphism of these two genes in samples of severe pre-eclamptic patients and healthy controls. Blood samples were collected from healthy pregnant normotensive women (n=82) and women with pre-eclampsia (n=75). DNA was isolated and quantitative real-time PCR method combined with melting curve analysis was performed for the detection of the two polymorphisms. Statistical analysis was performed with the STATISTICA software package. The frequency of the A allele in the RFC-1 gene was 46.57% by healthy pregnant and 41% by severe pre-eclamptic patients. The overall distribution of genotypes was not significantly different between the control and pre-eclamptic groups (p=0.58). In the study groups by the MTHFR gene the frequency of the T was 32% in pre-eclamptics, and 35.92% in controls. Similarly the overall distribution of genotypes was not significantly different between the two study groups (p=0.15). In hypertensive disorders of the pregnancy the one-carbon cycle is disturbed. We studied single nucleotide mutations in the genes of two enzymes involved in the cycle. We determined the allele and genotype frequencies in healthy control and pre-eclamptic patients and found no significant differences. Further examinations of other genetical compounds can help to understand the elevated homocysteine levels in pre-eclampsia.