There is no known cause, although research suggests the condition is produced by some form of intrauterine disturbance between the second and sixth months of pregnancy. In some cases, it can be discovered late in pregnancy, though more often it is often misdiagnosed as an excessive accumulation of cerebrospinal fluid in the brain, a condition called hydrocephalus. More often, colpocepaly is diagnosed after birth when seizures, signs of mental retardation and microcephaly become evident. No curative or restorative treatments exist for colpocephaly. Doctors may prescribe anticonvulsant drugs to prevent seizures, or other medications to prevent shrinkage or contractures of muscles.
Prognosis depends on the severity of the malformations and the amount of brain malformation.
In some cases, children with colpocepaly are able to participate in special education. The most serious form of holoprosencephaly is the alobar type, in which the brain halves completely fail to separate. It is characterized by severe facial and brain abnormalities, often so profound that they cause intrauterine death. Somewhat less severe is semilobar holoprosencephaly, in which the brain's hemispheres develop only a slight separation. Lobar holoprosencephaly, which is marked by substantial, but still incomplete, separation of the brain hemispheres is the least severe form.