What is a MTHFR Mutation?
An abnormal change in gene structure, called a mutation, of the MTHFR gene can cause a disruption of the MTHFR enzyme’s normal function of breaking down homocysteine. The two common MTHFR gene mutations occur at specific locations called “positions” along the gene. The one we generally test for is located at position 677. At this location, one amino acid base pair is different, in that Cytosine is replaced by Thymine. This mutation is thus called C677T. Another mutation we test for occurs at position 1298. At this location, Adenine is replaced by Cytosine and is therefore called A1298C. MTHFR mutations are common. The mutations can be “heterozygous” meaning they occur only on one strand or “allele” of the chromosome, or they can be “homozygous”, occurring on both alleles. The frequency of a heterozygous C677T mutation is common, occurring in about 35% of the population. The homozygous C677T mutation is about 5-10% of the population. A mutation in A1298T is more common but is generally
Related Questions
- Why does a mutation that deletes one or two DNA nucleotides changes gene function more drastically than a substitution of one nucleotide for another type?
- What type of mutation could result from a deletion of a single nucleotide from the DNA sequence?
- What is a mutation in which only one nucleotide or nitrogenous base in a gene is changed?
