mthfr gene mutation heterozygous
There are many combinations of MTHFR: 1  Homozygous: means you have both copies of either the 677 mutation, or the 1298 mutation, one from from each parent. 2  Heterozygous: means you have one copy of either the 677 mutation, or the 1298 mutation, plus a normal one from the other parent.ore than one mutation of the MTHFR gene. Genes are passed down by your mother and your father. Most literature states there are a good 40-50 different mutations of this important gene which could be passed down by one, or both or your parents.