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Genetics Home Reference: your guide to understanding genetic conditions
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Spina bifida

Reviewed November 2014

What is spina bifida?

Spina bifida is a condition in which the neural tube, a layer of cells that ultimately develops into the brain and spinal cord, fails to close completely during the first few weeks of embryonic development. As a result, when the spine forms, the bones of the spinal column do not close completely around the developing nerves of the spinal cord. Part of the spinal cord may stick out through an opening in the spine, leading to permanent nerve damage. Because spina bifida is caused by abnormalities of the neural tube, it is classified as a neural tube defect.

Children born with spina bifida often have a fluid-filled sac on their back that is covered by skin, called a meningocele. If the sac contains part of the spinal cord and its protective covering, it is known as a myelomeningocele. The signs and symptoms of these abnormalities range from mild to severe, depending on where the opening in the spinal column is located and how much of the spinal cord is affected. Related problems can include a loss of feeling below the level of the opening, weakness or paralysis of the feet or legs, and problems with bladder and bowel control. Some affected individuals have additional complications, including a buildup of excess fluid around the brain (hydrocephalus) and learning problems. With surgery and other forms of treatment, many people with spina bifida live into adulthood.

In a milder form of the condition, called spina bifida occulta, the bones of the spinal column are abnormally formed, but the nerves of the spinal cord usually develop normally. Unlike in the more severe form of spina bifida, the nerves do not stick out through an opening in the spine. Spina bifida occulta most often causes no health problems, although rarely it can cause back pain or changes in bladder function.

How common is spina bifida?

Spina bifida is one of the most common types of neural tube defect, affecting an estimated 1 in 2,500 newborns worldwide. For unknown reasons, the prevalence of spina bifida varies among different geographic regions and ethnic groups. In the United States, this condition occurs more frequently in Hispanics and non-Hispanic whites than in African Americans.

What genes are related to spina bifida?

Spina bifida is a complex condition that is likely caused by the interaction of multiple genetic and environmental factors. Some of these factors have been identified, but many remain unknown.

Changes in dozens of genes in individuals with spina bifida and in their mothers may influence the risk of developing this type of neural tube defect. The best-studied of these genes is MTHFR, which provides instructions for making a protein that is involved in processing the vitamin folate (also called vitamin B9). A shortage (deficiency) of this vitamin is an established risk factor for neural tube defects. Changes in other genes related to folate processing and genes involved in the development of the neural tube have also been studied as potential risk factors for spina bifida. However, none of these genes appears to play a major role in causing the condition.

Researchers have also examined environmental factors that could contribute to the risk of spina bifida. As mentioned above, folate deficiency appears to play a significant role. Studies have shown that women who take supplements containing folic acid (the synthetic form of folate) before they get pregnant and very early in their pregnancy are significantly less likely to have a baby with spina bifida or a related neural tube defect. Other possible maternal risk factors for spina bifida 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. However, it is unclear how these factors may influence the risk of spina bifida.

Related Gene(s)

Changes in this gene are associated with spina bifida.

  • MTHFR

How do people inherit spina bifida?

Most cases of spina bifida are sporadic, which means they occur in people with no history of the disorder in their family. A small percentage of cases have been reported to run in families; however, the condition does not have a clear pattern of inheritance. First-degree relatives (such as siblings and children) of people with spina bifida have an increased risk of the condition compared with people in the general population.

Where can I find information about diagnosis or management of spina bifida?

These resources address the diagnosis or management of spina bifida and may include treatment providers.

  • Benioff Children's Hospital, University of California, San Francisco: Treatment of Spina Bifida (http://www.ucsfbenioffchildrens.org/conditions/spina_bifida/treatment.html)
  • Centers for Disease Control and Prevention: Living with Spina Bifida (http://www.cdc.gov/ncbddd/spinabifida/living.html)
  • GeneFacts: Spina Bifida: Diagnosis (http://genefacts.org/index.php?option=com_content&view=article&id=445&Itemid=623)
  • GeneFacts: Spina Bifida: Management (http://genefacts.org/index.php?option=com_content&view=article&id=440&Itemid=624)
  • Genetic Testing Registry: Neural tube defect (http://www.ncbi.nlm.nih.gov/gtr/conditions/C0027794)
  • Genetic Testing Registry: Neural tube defects, folate-sensitive (http://www.ncbi.nlm.nih.gov/gtr/conditions/C1866558)
  • Spina Bifida Association: Urologic Care and Management (http://www.spinabifidaassociation.org/site/c.evKRI7OXIoJ8H/b.8277217/k.C15F/Urologic_Care_and_Management.htm)

You might also find information on the diagnosis or management of spina bifida in Educational resources (http://www.ghr.nlm.nih.gov/condition/spina-bifida/show/Educational+resources) and Patient support (http://www.ghr.nlm.nih.gov/condition/spina-bifida/show/Patient+support).

General information about the diagnosis (http://ghr.nlm.nih.gov/handbook/consult/diagnosis) and management (http://ghr.nlm.nih.gov/handbook/consult/treatment) of genetic conditions is available in the Handbook. Read more about genetic testing (http://ghr.nlm.nih.gov/handbook/testing), particularly the difference between clinical tests and research tests (http://ghr.nlm.nih.gov/handbook/testing/researchtesting).

To locate a healthcare provider, see How can I find a genetics professional in my area? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.

Where can I find additional information about spina bifida?

You may find the following resources about spina bifida helpful. These materials are written for the general public.

You may also be interested in these resources, which are designed for healthcare professionals and researchers.

What other names do people use for spina bifida?

  • cleft spine
  • open spine
  • rachischisis
  • spinal dysraphism

For more information about naming genetic conditions, see the Genetics Home Reference Condition Naming Guidelines (http://ghr.nlm.nih.gov/ConditionNameGuide) and How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.

What if I still have specific questions about spina bifida?

Ask the Genetic and Rare Diseases Information Center (http://rarediseases.info.nih.gov/GARD/).

What glossary definitions help with understanding spina bifida?

deficiency ; diabetes ; diabetes mellitus ; embryonic ; fever ; folate ; hydrocephalus ; inheritance ; maternal ; meningocele ; neural tube defects ; pattern of inheritance ; population ; prevalence ; protein ; risk factors ; seizure ; sporadic ; surgery

You may find definitions for these and many other terms in the Genetics Home Reference Glossary (http://www.ghr.nlm.nih.gov/glossary).

References

  • Au KS, Ashley-Koch A, Northrup H. Epidemiologic and genetic aspects of spina bifida and other neural tube defects. Dev Disabil Res Rev. 2010;16(1):6-15. doi: 10.1002/ddrr.93. Review. (http://www.ncbi.nlm.nih.gov/pubmed/20419766?dopt=Abstract)
  • Bassuk AG, Kibar Z. Genetic basis of neural tube defects. Semin Pediatr Neurol. 2009 Sep;16(3):101-10. doi: 10.1016/j.spen.2009.06.001. Review. (http://www.ncbi.nlm.nih.gov/pubmed/19778707?dopt=Abstract)
  • Botto LD, Moore CA, Khoury MJ, Erickson JD. Neural-tube defects. N Engl J Med. 1999 Nov 11;341(20):1509-19. Review. (http://www.ncbi.nlm.nih.gov/pubmed/10559453?dopt=Abstract)
  • Copp AJ, Greene ND. Genetics and development of neural tube defects. J Pathol. 2010 Jan;220(2):217-30. doi: 10.1002/path.2643. Review. (http://www.ncbi.nlm.nih.gov/pubmed/19918803?dopt=Abstract)
  • Doudney K, Grinham J, Whittaker J, Lynch SA, Thompson D, Moore GE, Copp AJ, Greene ND, Stanier P. Evaluation of folate metabolism gene polymorphisms as risk factors for open and closed neural tube defects. Am J Med Genet A. 2009 Jul;149A(7):1585-9. doi: 10.1002/ajmg.a.32937. (http://www.ncbi.nlm.nih.gov/pubmed/19533788?dopt=Abstract)
  • Greene ND, Stanier P, Copp AJ. Genetics of human neural tube defects. Hum Mol Genet. 2009 Oct 15;18(R2):R113-29. doi: 10.1093/hmg/ddp347. Review. (http://www.ncbi.nlm.nih.gov/pubmed/19808787?dopt=Abstract)
  • Martinez CA, Northrup H, Lin JI, Morrison AC, Fletcher JM, Tyerman GH, Au KS. Genetic association study of putative functional single nucleotide polymorphisms of genes in folate metabolism and spina bifida. Am J Obstet Gynecol. 2009 Oct;201(4):394.e1-11. doi: 10.1016/j.ajog.2009.06.042. Epub 2009 Aug 15. (http://www.ncbi.nlm.nih.gov/pubmed/19683694?dopt=Abstract)
  • Mitchell LE, Adzick NS, Melchionne J, Pasquariello PS, Sutton LN, Whitehead AS. Spina bifida. Lancet. 2004 Nov 20-26;364(9448):1885-95. Review. (http://www.ncbi.nlm.nih.gov/pubmed/15555669?dopt=Abstract)
  • Yan L, Zhao L, Long Y, Zou P, Ji G, Gu A, Zhao P. Association of the maternal MTHFR C677T polymorphism with susceptibility to neural tube defects in offsprings: evidence from 25 case-control studies. PLoS One. 2012;7(10):e41689. doi: 10.1371/journal.pone.0041689. Epub 2012 Oct 3. (http://www.ncbi.nlm.nih.gov/pubmed/23056169?dopt=Abstract)
  • Zhang T, Lou J, Zhong R, Wu J, Zou L, Sun Y, Lu X, Liu L, Miao X, Xiong G. Genetic variants in the folate pathway and the risk of neural tube defects: a meta-analysis of the published literature. PLoS One. 2013 Apr 4;8(4):e59570. doi: 10.1371/journal.pone.0059570. Print 2013. (http://www.ncbi.nlm.nih.gov/pubmed/23593147?dopt=Abstract)

 

The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.

 
Reviewed: November 2014
Published: December 16, 2014