Abstract
Paired-like homeobox 2B (PHOX2B) is a gene essential in the development of the autonomic nervous system.PHOX2Bmutations are associated with neurocristopathies—Hirschsprung disease (HSCR) and congenital central hypoventilation syndrome (CCHS)—and peripheral neuroblastic tumours. PHOXB2 plays an important role in the diagnostics of these conditions.Genotyping of aPHOX2Bpathogenic variant is required to establish a diagnosis of CCHS. In HSCR patients, PHOX2B immunohistochemical staining has proven to be a valuable tool in identifying this disease. Furthermore,PHOXB2is a predisposition gene for neuroblastoma, in which PHOX2B immunohistochemical staining can be used as a highly sensitive and specific diagnostic marker. The utility of PHOX2B immunohistochemistry in pheochromocytoma and paraganglioma has also been studied but yields conflicting results.In this review, an overview is given ofPHOX2B, its associated diseases and the usefulness of PHOX2B immunohistochemistry as a diagnostic tool.