Holoprosencephaly
| Holoprosencephaly | |
|---|---|
 |
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| Diagram depicting the main subdivisions of the embryonic vertebrate brain. | |
| Classification and external resources | |
| Specialty | Medical genetics |
| ICD-10 | Q04.2 |
| ICD-9-CM | 742.2 |
| OMIM | 236100 |
| DiseasesDB | 29610 |
| eMedicine | radio/347 |
| MeSH | D016142 |
| GeneReviews | |
| Orphanet | 2162 |
Holoprosencephaly (HPE) is a cephalic disorder in which the prosencephalon (the forebrain of the embryo) fails to develop into two hemispheres. Normally, the forebrain is formed and the face begins to develop in the fifth and sixth weeks of human pregnancy. The condition also occurs in other species.
The condition can be mild or severe. According to the National Institute of Neurological Disorders and Stroke (NINDS), "in most cases of holoprosencephaly, the malformations are so severe that babies die before birth."
When the embryo's forebrain does not divide to form bilateral cerebral hemispheres (the left and right halves of the brain), it causes defects in the development of the face and in brain structure and function.
In less severe cases, babies are born with normal or near-normal brain development and facial deformities that may affect the eyes, nose, and upper lip.
Symptoms of holoprosencephaly range from mild (no facial/organ defects, anosmia, or only a single central incisor) to moderate to severe (cyclopia).
There are four classifications of holoprosencephaly.
Holoprosencephaly consists of a spectrum of defects or malformations of the brain and face. At the most severe end of this spectrum are cases involving serious malformations of the brain, malformations so severe that they often cause miscarriage or stillbirth. At the other end of the spectrum are individuals with facial defects which may affect the eyes, nose, and upper lip - and normal or near-normal brain development. Seizures and mental retardation may occur.
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Wikipedia