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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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Inheritance

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Is anencephaly inherited?

Most cases of anencephaly are sporadic, which means they occur in people with no family history of anencephaly or other neural tube defects (NTDs). In some cases, it may be associated with a chromosome abnormality, a severe malformation syndrome, or disruption of the amniotic membrane.[1] A small portion of cases have appeared to be familial, but it often does not have a clear inheritance pattern.[2] In isolated populations, anencephaly has been suspected to be due to a single gene. In Iranian Jews, who have high rates of consanguinity (mating with family members), it is inherited in an autosomal recessive manner.[3]

Parents who have had a child with anencephaly are at an increased risk to have another affected child (compared with the risk in the general population).[2] Because most cases are believed to be multifactorial (due to interaction of genetic and environmental factors), the recurrence risk is estimated to be between 2% and 5% after a single case.[3] If anencephaly is known to be associated with an underlying disorder, the recurrence risk may depend on that of the underlying disorder.

For women who have previously had a fetus or infant with anencephaly, the Centers for Disease Control and Prevention (CDC) recommends increasing the intake of folic acid to 4mg per day beginning at least one month prior to conception.[3]

People who have had a pregnancy or child with anencephaly or another NTD, and have questions about future risk, are encouraged to speak with a genetic counselor or other genetics professional.
Last updated: 8/31/2015

References
  1. Robert G Best. Anencephaly. Medscape Reference. November, 2013; http://emedicine.medscape.com/article/1181570-overview.
  2. Anencephaly. Genetics Home Reference. November, 2014; http://ghr.nlm.nih.gov/condition/anencephaly.
  3. Diana W. Bianchi, Timothy M. Crombleholme, Mary E. D'Alton, Fergal D. Malone. Management of fetal conditions diagnosed by sonography. Fetology: Diagnosis and Management of the Fetal Patient, Second Edition. McGraw-Hill Companies; 2010; 77-82.


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.