The existence of an PHOX2B-related predisposition to neuroblastic tumors is suspected in a person who exhibits the following:
The diagnosis of a “PHOX2B-related predisposition to neuroblastic tumors” is confirmed by detection of a mutation – or genetic change – in the PHOX2B gene.
Patients with a PHOX2B-related predisposition to neuroblastic tumors are at increased risk of developing neuroblastic tumors, such as the following:
In addition, there is an increased risk of developing congenital central hypoventilation syndrome (CCHS). This congenital disease of the nervous system is associated with disruption or absent control of autonomic respiration, which is usually more pronounced during sleep than when awake.
Another disease that occurs with PHOX2B mutations is Hirschsprung’s disease, also called congenital megacolon. In this disease, a lacking neural supply in parts of the big intestine causes a constriction in a section of the bowel, leading to considerable constipation. The ensuing backup of feces results in the bowel section above the constricted point to expand, leading to flatulence and vomiting.
Moreover, a few patients with a PHOX2B mutation exhibit facial anomalies, such as drooping palpebral fissures, a narrow nose, a triangular mouth, or low-lying ears that are rotated towards the back.