What is polymorphism in the MTHFR gene?
A common polymorphism in the gene coding for the 5,10-methylene tetrahydrofolate reductase (MTHFR) (C677T, Ala –> Val) is associated with a decreased activity of the enzyme due to thermolability.
What is the C677T polymorphism in the MTHFR gene?
The C677T polymorphism is a point mutation at the position 677 on MTHFR gene with the substitution of cysteine to thymine nucleotide at that position. This point mutation causes the substitution of alanine to valine in the MTHFR enzyme [Rosenberg et al., 2002].
What is compound heterozygous MTHFR mutation C677T A1298C?
For MTHFR mutations, the C677T variant results in substitution of the amino acid alanine for valine. The A1298C variant results in an alanine substitution (versus a glutamine). The C677T valine substitution results in a less active form of the MTHFR enzyme.
What if both parents have MTHFR?
Mutations can occur in one or both of these genes. Having a parent or close relative with an MTHFR gene mutation can increase a person’s risk of inheriting the same variant themselves. People who have two parents with a mutation have an increased risk of having a homozygous MTHFR mutation.
What does MTHFR A1298C heterozygous mean?
Being homozygous for MTHFR A1298C leads to 60% of normal enzyme function. People may also have 1 abnormal MTHFR C677T gene plus 1 abnormal MTHFR A1298C gene; this is termed double heterozygous. Decreased enzyme function may also result.
Is MTHFR passed from mother or father?
Genes are the basic units of heredity passed down from your mother and father. Everyone has two MTHFR genes, one inherited from your mother and one from your father. Mutations can occur in one or both MTHFR genes. There are different types of MTHFR mutations.
How common is MTHFR C677T mutation?
There are two MTHFR gene variants, called C677T and A1298C, that have been an active area of study. These variants are common. In America, about 25% of people who are Hispanic, and 10-15% of people who are Caucasian have two copies of C677T.
What is the C677T mutation?
The most common MTHFR mutation is called the MTHFR C677T mutation. The mutation is extremely common in certain ethnic and geographic populations. In the United States, ≈20% to 40% of white and Hispanic individuals are heterozygous for MTHFR C677T. The mutation is less common in blacks (1%–2%).
How are C677T and A1298C MTHFR polymorphisms impact on enzymatic activity?
Other MTHFR polymorphisms with marginal impact on enzymatic activity were also reported. Several published clinical studies have investigated the potential predictive role of C677T and A1298C genetic variants on toxicity and efficacy of antifolate and fluoropyrimidine agents, such as methotrexate (MTX), 5-fluorouracil (5-FU) and raltitrexed.
What happens if you have both C677T and A1298C mutations?
Acquiring both C677T and A1298C mutations (one copy of each) is called double or compound heterozygous variation. This mutation also results in decreased enzyme function. Everyone is affected differently, but research has shown a link between MTHFR gene mutations and the following health conditions:
What is the difference between MTHFR c1298c and C677T?
MTHFR C1298C = homozygous mutation (two mutations) MTHFR C677T + MTHFR A1298C = a compound heterozygous mutation One of the biggest concerns for those with an MTHFR mutation is the effect it may have on homocysteine levels in the blood.
Can a heterozygous A1298C mutation cause heart disease?
It was concluded that a heterozygous A1298C mutation on its own does not influence heart disease risk. Summary: High homocysteine is an independent risk factor for numerous diseases. Those with a homozygous or compound heterozygous MTHFR mutations are more likely to have elevated homocysteine and greater risk of heart disease.