NNMT and coronary artery disorder: Nicotinamide N‐methyltransferase (NNMT) gene is abundantly expressed in adipose tissue and liver and lower expressed in other organs.1, 2 NNMT behaves as an important methyltransferase to catalyze the transfer of a methyl group from s‐adenosylmethionine to nicotinamide (vitamin B3) to generate N1‐methylnicotinamide (me‐NAM) and s‐adenosylhomocysteine, a precursor of homocysteine,1, 2 and is therefore considered to play a unique role in the development of coronary artery disease (CAD) because it has long been known that elevated homocysteine is associated with cardiovascular disease.3