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Diseases

Genetic and Rare Diseases Information Center (GARD)

Anencephaly


Other Names for this Disease
  • Absence of a large part of the brain and the skull
  • Isolated anencephaly/exencephaly
Related Diseases
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Cause

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What causes anencephaly?

The underlying cause of anencephaly is not fully understood. Like other forms of neural tube defects (NTDs), anencephaly is likely caused by the interaction of multiple genes and environmental factors, many of which remain unknown.[1]

Variations in many genes may influence the risk of developing anencephaly. The best-studied gene thus far is the MTHFR gene, which gives the body instructions to make a protein used to process the vitamin folate (also called vitamin B9). A deficiency of folate is a known risk factor for NTDs. Other genes involved in folate processing, and the development of the neural tube, may also affect the risk.

Researchers have also looked at environmental factors that could contribute to the risk of anencephaly. Folate appears to play a significant role, and studies have shown that taking folic acid (a form of folate), before getting pregnant and very early in pregnancy, significantly reduces the risk to have a baby with a NTD. Other possible maternal risk factors for anencephaly include diabetes mellitus; obesity; exposure to high heat (such as a fever or use of a hot tub or sauna) in early pregnancy; and the use of certain anti-seizure medications during pregnancy.[1]
Last updated: 8/31/2015

References
  1. Anencephaly. Genetics Home Reference. November, 2014; http://ghr.nlm.nih.gov/condition/anencephaly.


Other Names for this Disease
  • Absence of a large part of the brain and the skull
  • Isolated anencephaly/exencephaly
Related Diseases
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.