Ethmocephaly is a type of cephalic disorder caused by holoprosencephaly.
Ethmocephaly is the rarest phenotypic variant of a group of defects called the holoprosencephaly (HPE) malformation sequence; other variants include cebocephaly, cyclopia, and median cleft palate.
Cebocephaly, another facial anomaly, is characterized by a small, flattened nose with a single nostril situated below incomplete or underdeveloped closely set eyes.
The least severe in the spectrum of facial anomalies is the median cleft lip, also called premaxillary agenesis.
If no cause is identified and the fetal chromosomes are normal, the chance to have another pregnancy affected with holoprosencephaly is about 6%.