MTHFR rs1801131 – A1298C (qPCR)

Description

The MTHFR rs1801131 – A1298C (qPCR) product is used for genotyping the rs1801131 polymorphism located within the human MTHFR gene encoding methylenetetrahydrofolate reductase (MTHFR). The material for analysis are DNA preparations containing human genetic material.

Product characteristics

Kit size: 100 reactions

Reaction: allelic discrimination using Taqman probes (FAM: wild-type allele, HEX: allele carrying the A1298C mutation)

Determination: qualitative/quantitative

Kit components:

• Reaction mixture: contains DNA polymerase, probes and primers, and other qPCR reaction components;
• Mieszanina reakcyjna: zawiera polimerazę DNA, sondy i startery oraz inne składniki reakcji qPCR;
• Controls positive for both detected alleles;
• Negative control;
• PCR-grade water

How the product works

The MTHFR rs1801131 – A1298C (qPCR) product is based on the Taqman probe genotyping technique. The DNA fragment surrounding the rs1801131 polymorphism is amplified by a pair of primers and detected by a pair of Taqman probes. The FAM-labeled probe is complementary to the DNA region containing thymine (wild-type allele, T allele), while the HEX-labeled probe is complementary to the DNA region with a sequence containing guanine (mutated allele, G allele).

During the reaction, these probes compete with each other to bind to the matrix. A probe that is 100% homologous to the DNA strand binds preferentially to it over the alternative probe. As the reaction progresses, a strong signal appears for the fully homologous probe and a weak signal for the alternative probe. The genotype of the sample is determined by comparing the signal intensity ratio between the two channels (FAM and HEX). For homozygous samples, a strong signal is obtained on one channel and a weak signal on the other channel. For heterozygous samples, which contain binding sites for each probe, an intermediate signal is obtained on both channels.

Description of polymorphism rs1801131

The rs1801131 polymorphism results in an A->C transversion at position 1298 of the MTHFR mRNA. This leads to the replacement of glutamic acid with alanine at position 429 of the MTHFR protein. Hence, this polymorphism is known as A1298C or E429A. The amino acid replacement reduces the activity of methylenetetrahydrofolate reductase. In EA heterozygotes, MTHFR activity is reduced by 8-40% compared to individuals with the EE genotype. In homozygotes, enzyme activity is reduced by approximately 40-48%.

According to the current nomenclature in the dbSNP (NCBI) database, the rs1801131 polymorphism involves the replacement of a thymidine nucleotide with a guanine nucleotide (T->G) at position 11794419 on chromosome 1. This is due to the fact that the MTHFR gene is encoded by the complementary strand of chromosome 1.

The rs1801131 polymorphism, and rs1801133 polymorphism, which also results in reduced MTHFR activity, has been linked to a number of disorders, including:

• hyperhomocysteinemia (abnormally high levels of homocysteine in the blood or urine);
• cardiovascular disease (ischemic heart disease, blood clots, stroke, and heart attack);
• congenital abnormalities: (neural tube defects, microcephaly);
• dementia;
• mental illness (people with the MTHFR gene variant may be more prone to depression);
• drug toxicity: people with the MTHFR gene variant may be at greater risk of toxicity from drugs that affect folate homeostasis, such as methotrexate (MTX);
• peripheral neuropathy (nerve damage).