MTHFD1 (Methylenetetrahydrofolate Dehydrogenase 1): MTHFD1 is a key enzyme in the folate metabolism pathway, catalyzing the conversion of tetrahydrofolate (THF) derivatives into forms used for the synthesis of DNA, RNA, and amino acids. It plays a vital role in one-carbon metabolism, influencing cellular methylation reactions and nucleotide production. Mutations or dysregulation of MTHFD1 can disrupt folate metabolism and are associated with an increased risk of congenital defects, cardiovascular diseases, and cancer.