The nucleotide pyrophosphatase/phosphodiesterase (NPP) family is a group of enzymes with various functions, primarily including members NPP1 to NPP5. These enzymes are typically located on the cell membrane and are responsible for hydrolyzing molecules such as extracellular nucleotides and phospholipids, participating in biological processes such as signal transduction, cell proliferation, migration, and apoptosis. NPP family members exhibit tissue-specific expression; for example, NPP1 is highly expressed in bone and immune cells, while NPP2 is active in the nervous and cardiovascular systems. Mutations or abnormal expression of these genes are associated with various diseases such as atherosclerosis, cancer, and inflammatory conditions.