MTHFD1 (Methylenetetrahydrofolate Dehydrogenase 1): MTHFD1 is a crucial enzyme in the folate metabolism pathway, catalysing the conversion of tetrahydrofolate (THF) derivatives into forms utilised for synthesising DNA, RNA, and amino acids. It plays an essential role in one-carbon metabolism, affecting cellular methylation reactions and nucleotide production. Mutations or dysregulation of MTHFD1 can disrupt folate metabolism and are linked to a higher risk of congenital defects, cardiovascular diseases, and cancer.