ENPP4 (Ectonucleotide Pyrophosphatase/Phosphodiesterase 4): ENPP4 is a gene that encodes an enzyme from the ENPP family, involved in purinergic signaling and phosphate balance. ENPP4 acts as both a phosphodiesterase, breaking down phosphodiester bonds, and a pyrophosphatase, cleaving pyrophosphate bonds. It is primarily expressed in the kidney, liver, and brain, where it contributes to processes such as bone mineralization, lipid metabolism, and regulation of extracellular nucleotides. ENPP4 may also influence immune responses and inflammation through purinergic receptor interactions.