Arrhinencephaly

• also called olfactory aplasia
• This term has been used as a synonym for holoprosencephaly. However, more recently it has been used to denote a condition where there is variable absence of the olfactory bulbs, tracts and anterior perforating substance without fusion of the hemispheres.
• It may represent the mildest form of telencephalic failure.

See Patau Syndrome