The Interweaving of B9- and B12-Dependent Reactions and Their Clinical Implications

FolateFolate (vitamin B9Vitamin B9) and vitamin B12 (cobalaminCobalamin) are part of the one-carbon metabolismOne-carbon metabolism pathways. Both of them are water-soluble compounds and play an essential role in DNA production, amino acid homeostasis, antioxidantAntioxidant activities and epigeneticEpigenetics regulation. These vitamins are involved in very few reactions in the human body, yet they are vital to normal functioning of the cells. In synergy, these vitamins play an essential role in the conversion of homocysteineHomocysteine to S-adenosyl methionineMethionine (the universal methyl donor) via methionine. Through these reactions they ensure appropriate cell division and maturation via their impact on DNA synthesis and metabolismMetabolism, regulation of gene expression and maintenance of chromosome conformation. It follows that any aberrations in these reactions (as may occur due to deficiencyDeficiency of these vitamins) have far reaching effects that encompass foetal development, haematopiesis, the circulatory systemCirculatory system, the nervous systemNervous system, genetic aberrations, epigeneticEpigenetics transformations, malignanciesMalignancies and ageing, i.e. from conception to demise.