Final answer:
Variations in the Methylene tetrahydrofolate reductase (MTHFR) gene in mothers can increase the risk of neural tube defects in their offspring by affecting folate metabolism and homocysteine levels.
Step-by-step explanation:
In mothers, variation in the Methylene tetrahydrofolate reductase (MTHFR) gene increases the susceptibility of their offspring to neural tube defects. The MTHFR gene is crucial in the process involving folate metabolism and conversion of homocysteine to methionine. A deficiency or abnormality in this gene may lead to elevated levels of homocysteine, which is associated with a higher risk of neural tube defects like spina bifida and anencephaly in the developing fetus.