Holoprosencephaly is a congenital disease characterized by failure in the formation of the midline brain segments including the anterior part of the corpus callosum, falx cerebri, and septum pellucidum. Holoprosencephaly means "total prosencephalon," which is one of the three primitive vesicles of the early human brain. In holoprosencephaly, both lateral ventricles and the third ventricle become one big ventricle. The incidence is 1 in every 16,000 births.
Holoprosencephaly can be associated with hypotelorism, trisomy 13, Kallmann syndrome (congenital absence of the olfactory nerve with hypogonadotrophic hypogonadism), and trisomy 18. Moreover, it is commonly associated with facial anomalies such as:
- Cyclopia: both orbits and eyes are fused into one eye.
- Ethmocephaly: both orbits are very near each other but not fused.
- Cebocephaly: small flat nose with single nostril.
- Cleft lip.
There are three types of holoprosencephaly:
- Alobar Holoprosencephaly.
- Semilobar Holoprosencephaly.
- Lobar Holoprosencephaly.
For Further Reading
- Fitz CR. Holoprosencephaly and related entities. Neuroradiology 1983;25:225–238.
- Sener RN. Anterior callosal agenesis in mild, lobar holoprosencephaly. Pediatr Radiol 1995;25:385–386.
- Osaka K et al. Dysgenesis of the deep venous system diagnostic criterion for holoprosencephaly. Neuroradiology 1977;13:231–238.
- Maki Y et al. Angiographic features of alobar holoprosencephaly. Neuroradiology 1974;6:270–276.