Arhinia revisited.

Arhinia is a rare anomaly in which a total absence of the nose and parts of the olfactory system occurs. It is frequently associated with various multiple central nervous system (CNS) and somatic anomalies of different degrees of severity, with high mortality rate. Twelve cases that have been reported in the literature are analyzed according to multiple criteria. The anomalies that have been found to be associated with arhinia are: lack of olfactory bulbs and nerves, missing paranasal sinuses, high arched or cleft palate, various eye anomalies, low set ears - all in a very high incidence. Various degrees of CNS malformations have been found in part of the cases. Somatic anomalies have been reported in 50% of the cases. In two cases chromosome 9 anomalies have been reported. A classification is suggested in which arhinia is classified into arhinia (total absence of the nose and rhinencephalon) and partial arhinia (partial absence of the nose), each may or may not be associated with other malformations (facial, CNS and somatic).