Holoprosencephaly is a disorder caused by the failure of the prosencephalon (the embryonic forebrain) to sufficiently divide into the double lobes of the cerebral hemispheres.
The result is a single-lobed brain structure and severe skull and facial defects.
Babies born with Holoprosencephaly can have normal or near-normal brain development along with facial deformities that may affect the eyes, nose, and upper lip.
There are Three Classifications of Holoprosencephaly
- Alobar, in which the brain has not divided at all, is usually associated with severe facial deformities.
- Semilobar, in which the brains hemispheres have somewhat divided, causes an intermediate form of the disorder.
- Lobar, in which there is considerable evidence of separate brain hemispheres, is the least severe form. In some cases of Lobar Holoprosencephaly the baby’s brain may be nearly normal.
The least severe of the facial anomalies is the median cleft lip (premaxillary agenesis). The most severe is cyclopia, an abnormality characterized by a single eye located in the area normally occupied by the root of the nose, and a missing nose or a proboscis (a tubular-shaped nose) located above the eye.
The least common facial anomaly is ethmocephaly, in which a proboscis separates closely-set eyes. Cebocephaly, another facial anomaly, is characterized by a small, flattened nose with a single nostril situated below incomplete or underdeveloped closely-set eyes.
What is the cause of Holoprosencephaly?
The cause is unknown.
Is there any treatment?
There is no standard course of treatment for Holoprosencephaly. Treatment is symptomatic and supportive.
Where Can I Get More Information?
Carter Centers for Research in Holoprosencephaly
c/o Texas Scottish Rite Hospital P.O. Box 190567
2222 Welborn Street
Dallas, TX 75219-9982
National Organization for Rare Disorders (NORD)
P.O. Box 1968
(55 Kenosia Avenue)
Danbury, CT 06813-1968
Tel: 203-744-0100 Voice Mail 800-999-NORD (6673)