The PHOX2B gene is located on the fourth chromosome in humans and leads to the synthesis of a protein with the same name as it. This protein is synthesized not only in the central nervous system but also in the peripheral nervous system. When this gene and protein work in a healthy way, it allows the nerves of the sympathetic system to differentiate and continue their lives. In addition, neuroblastoma cells, which are nervous system tumors, also synthesize this protein. In fact, for this reason, this protein is also called neuroblastoma Phox.