Exencephaly

Exencephaly is a type of cephalic disorder wherein the brain is located outside of the skull. This condition is usually found in embryos as an early stage of anencephaly. As an exencephalic pregnancy progresses, the neural tissue gradually degenerates.

The prognosis for infants born with exencephaly is extremely poor. It is rare to find an infant born with exencephaly, as most cases that are not early stages of anencephaly are usually stillborn. Those infants who are born with the condition usually die within hours.

Pathophysiology

Relation to other rare disorders: genetic ciliopathy

Until recently, the medical literature did not indicate a connection among many genetic disorders, both genetic syndromes and genetic diseases, that are now being found to be related. As a result of new genetic research, some of these are, in fact, highly related in their root cause despite the widely-varying set of medical symptoms that are clinically visible in the disorders. Exencephaly is one such disease that has recently been identified as part of an emerging class of diseases called cilopathies. The underlying cause may be a dysfunctional molecular mechanism in the primary cilia structures of the cell, organelles which are present in many cellular types throughout the human body. The cilia defects adversely affect "numerous critical developmental signaling pathways" essential to cellular development and thus offer a plausible hypothesis for the often multi-symptom nature of a large set of syndromes and diseases. Known ciliopathies include primary ciliary dyskinesia, Bardet-Biedl syndrome, polycystic kidney and liver disease, nephronophthisis, Alstrom syndrome, Meckel-Gruber syndrome and some forms of retinal degeneration. [cite journal
last = Badano
first = Jose L.
authorlink =
coauthors = Norimasa Mitsuma, Phil L. Beales, Nicholas Katsanis
title = The Ciliopathies : An Emerging Class of Human Genetic Disorders
journal = Annual Review of Genomics and Human Genetics
volume = 7
issue =
pages = 125-148
publisher =
location =
date = September 2006
url = http://arjournals.annualreviews.org/doi/abs/10.1146/annurev.genom.7.080505.115610
doi = 10.1146/annurev.genom.7.080505.115610
id =
accessdate = 2008-06-15] .

ee also

*Anencephaly

Notes

External links

* [http://www.ninds.nih.gov/disorders/cephalic_disorders/detail_cephalic_disorders.htm NINDS Overview]
* [http://www.obgyn.net/us/cotm/0006/Exencephaly-Anencephaly.htm Obgyn.net]