NINDS Holoprosencephaly Information Page: NINDS

Article title: NINDS Holoprosencephaly Information Page: NINDS

Conditions: Holoprosencephaly

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What is Holoprosencephaly?
Holoprosencephaly is a disorder caused by the failure of the prosencephalon (the forebrain of the embryo) to divide to form bilateral cerebral hemispheres, causing defects in the development of the face and in brain structure and function. Once called arhinencephaly, the disorder consists of a spectrum of defects or malformations of the brain and face. Most cases are associated with severe malformations of the brain which are incompatible with life and often cause spontaneous intrauterine death. 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. The most severe of the facial anomalies 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 nose in the form of a proboscis (a tubular appendage), located above the eye. Ethmocephaly is the least common facial anomaly. It consists of a proboscis separating narrow-set eyes with an absent nose and microphthalmia (abnormal smallness of one or both eyes). 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. There are three classifications of holoprosencephaly. Alobar, the most serious form in which the brain has no tendency to separate, is usually associated with severe facial anomalies. Semilobar, in which the brain's hemispheres have a slight tendency to separate, is an intermediate form of the disease. Lobar, in which there is considerable evidence of separate brain hemispheres, is the least severe form. In some cases of lobar holoprosencephaly the patient's brain may be nearly normal.

Is there any treatment?
There is no standard course of treatment for holoprosencephaly. Treatment is symptomatic and supportive.

What is the prognosis?
The prognosis for individuals with the disorder is poor. Most of those who survive show no significant developmental gains.

What research is being done?
The NINDS supports and conducts a wide range of studies which focus on identifying and learning more about the genes and other factors involved in normal brain development. The knowledge gained from these fundamental studies provides the foundation for understanding how this process can go awry and, thus, may eventually give clues to understanding disorders such as holoprosencephaly.

 Organizations

The ARC
1010 Wayne Avenue
Suite 650
Silver Spring, MD 20910
Info@thearc.org
http://www.thearc.org/
Tel: 301-565-3842
Fax: 301-565-3843 or -5342

March of Dimes Birth Defects Foundation
1275 Mamaroneck Avenue
White Plains, NY 10605
resourcecenter@modimes.org
http://www.modimes.org/
Tel: 914-428-7100 888-MODIMES (663-4637)
Fax: 914-428-8203

Carter Centers for Research in Holoprosencephaly
c/o Texas Scottish Rite Hospital P.O. Box 190567
2222 Welborn Street
Dallas, TX 75219-9982
nclegg@tsrh.org
http://www.stanford.edu/group/hpe
Tel: 214-559-8411
Fax: 214-559-8383

National Organization for Rare Disorders (NORD)
P.O. Box 8923
(100 Route 37)
New Fairfield, CT 06812-8923
orphan@rarediseases.org
http://www.rarediseases.org/
Tel: 203-746-6518 800-999-NORD (6673)
Fax: 203-746-6481

National Institute of Child Health and Human Development (NICHD)
National Institutes of Health
Bldg. 31, Rm. 2A32
Bethesda, MD 20892-2425
NICHDClearinghouse@mail.nih.gov
http://www.nichd.nih.gov/
Tel: 301-496-5133 800-370-2943

This fact sheet is in the public domain. You may copy it.Provided by:
The National Institute of Neurological Disorders and Stroke
National Institutes of Health
Bethesda, MD 20892

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