Anencephaly Information
Home	Stories	Pictures	Facts	Prepare	Network	Family	Comfort	Links	About us	Sitemap

What is a neural tube defect?

Anencephaly is due to failure of primary neurulation (neurulation is the process which progenitors of the central nervous system are shaped, separated from and brought beneath the epidermis). In the normal human embryo, the neural plate arises approximately 18 days after fertilization (fig 2 and 3). During the fourth week of development, the neural plate invaginates along the embryonic midline to form the neural groove. The neural tube is formed as closure of the neural groove proceeds from the middle of the groove and progresses toward the ends in both directions, with completion between day 24 for the cranial end and day 26 for the caudal end (fig. 4). Disruptions of the normal closure process give rise to neural tube defects (NTDs). Anencephaly results from failure of neural tube closure at the cranial end of the developing embryo. Absence of the brain and calvaria may be partial or complete.


flatplate stage	deepening neural groove	neural folds in apposition	neural tube formed

fig. 2 Neural tube closure: sagital sections of 1-cell frog embryos

(click on the tumbnails to enlarge the pictures)

pictures used with the permission of Lance Davidson

fig. 3 Sagital section of neural plate becoming the neural tube

fig. 4 Developpement of the neural tube

fig. 5 Neural tube, picture from the book "A Child is Born" by Lennart Nilsson. Click on the tumbnail to enlarge the picture.

Check out a cool animation of neurulation and closure of the neural tube: http://learningobjects.wesleyan.edu/neurulation/animation.php

Duke CHG Research on Anencephaly and other NTDs

The Duke Center for Human Genetics is currently conducting a genetic study called "The Hereditary Basis of Neural Tube Defects" to determine the causes of anencephaly and other NTDs. By studying families with anencephaly and other NTDs, they hope to identify the genes that contribute to the development of the neural tube. They hope this research will eventually lead to more accurate genetic counseling and risk assessment, improved treatments, better prevention methods, and possibly, a cure.

More information and how to participate: http://www.chg.duke.edu/diseases/anencephaly.html

More medical information about anencephaly:

* Robert G. Best, Professor Departement of Obstetrics and Gynecologie wrote a very good article about anencephaly: http://www.emedicine.com/neuro/topic639.ht

* National Institute of Neurological Disorders and Stroke

Anencephaly Information Page: http://www.ninds.nih.gov/health_and_medical/disorders/anencephaly_doc.htm

Cephalic Disorders Fact Sheed: http://www.ninds.nih.gov/health_and_medical/pubs/cephalic disorders.htm

I put together some articles around research about anencephaly:

Why did the United States decide to fortify food and implement public campaigns?

Suggestion for change of recommended use of folic acid to reduce neural tube defects.

Are We Seeing Other Birth Defects Prevention Benefits from Folic Acid?

Dieting, Diet-Related Behaviors and Risk of Neural Tube Defects.

Case-Control Study of Association of Maternal Recall of Diarrhea and Use of Antimicrobials in the Periconceptional Period and Risk of NTDs.

The Relationship Between Neural Tube Defects of Congenital Cardiovascular Malformations and Spontaneous Abortion in a Previous Pregnancy.

More medical l inks about anencephaly

References:

Sadler TW, 1998. Mechanisms of neural tube closure and defects. Ment Retard Dev Disabil Res Rev 1998;4:247-53

Sadler TW. 2005. Embryology of Neural Tube Development. American Journal of Medical Genetics Part C 135C:2-8

home

webmaster