NAMPT (Nicotinamide phosphoribosyltransferase) is a critical enzyme involved in the biosynthesis of nicotinamide adenine dinucleotide (NAD+), which exists both intra- and extracellularly. As a key enzyme in the production of NAD+, NAMPT is expressed in various cells and tissues, particularly in immune cells, liver, and adipose tissue. NAMPT regulates processes such as energy metabolism, DNA repair, cell death, and immune responses. Gene expression is regulated by nutritional status, inflammation, and stress responses. Variations or changes in the expression levels of the NAMPT gene are associated with the development of various diseases including obesity, diabetes, cardiovascular diseases, and cancer.