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Genetic and Rare Diseases Information Center (GARD)


Other Names for this Disease
  • Encephalomeningocele
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.

Your Question

What causes an infant to be born with this condition? My 9 month old baby boy had surgery to repair this after months of us being told he had allergies, although it was clear he had an obstruction in his nasal cavity and he was not able to breath well since birth. Also, is this a hereditary condition? How many infants are diagnosed with this? What are the long term affects even after repair?

Our Answer

We have identified the following information that we hope you find helpful. If you still have questions, please contact us.

What causes meningoencephalocele?

The exact cause of meningoencephalocele is not known. Some studies have suggested that environmental factors could play a role in causing the condition. Exposure during pregnancy to aflatoxins, toxins produced by a mold that grows in nuts, seeds, and legumes, has been proposed to be a possible cause in some cases. However, its potential role in causing the condition is unclear. It has also been suggested that folate deficiency during pregnancy might play a role, because the condition is so closely related to spina bifida, which can be caused by folate deficiency. However, there have been no studies regarding the relationship of maternal folate deficiency and meningoencephalocele. Further studies are needed to to clarify what may cause the condition.[1]
Last updated: 9/21/2011

Is meningoencephalocele inherited?

Meningoencephalocele is not thought to be an inherited condition. Studies have proposed that meningoencephalocele is likely a multifactorial defect. This means that both environmental factors and multiple genes may interact with each other to cause the condition. Studies have suggested that environmental factors probably play an important role. This information is supported by the fact that several studies have not identified the condition among close relatives of affected individuals. To date, there have been no genes identified that are likely to play a strong part in causing the condition.[1]
Last updated: 9/21/2011

How many infants have been diagnosed with meningoencephalocele?

The exact number of individuals diagnosed with meningoencephalocele is not known. Although the term "meningoencephalocele" refers specifically to the protrusion of both meninges and brain tissue due to a skull defect, this condition is sometimes more generally referred to as an "encephalocele" which may encompass all conditions characterized by herniation of any intracranial material due to a cranial defect. The worldwide frequency of encephaloceles in general is not exactly known but has been reported to vary between 1/2500 and 1/10,000 individuals.[2] For unknown reasons, the incidence of frontoethmoidal encephalocele (relating to the ethmoid and frontal bones) is highest in Southeast Asia.
Last updated: 9/21/2011

What is the long-term prognosis for individuals with meningoencephalocele?

The prognosis for each individual with meningoencephalocele depends on the size and location of the sac, whether brain tissue is present in the sac, and if other brain abnormalities are also present.[2]  Survival is generally better when brain tissue is not involved in the sac.[3]  Individuals with encephaloceles located in the face (at the frontal and nasal bones) tend to have better survival and development than those located at the back of the head (at the occipital and parietal bones).[4][3]  Several studies have found that approximately two-thirds (66%) of individuals with meningoencephalocele in the back of the head survive[3][2]; of those survivors, approximately half have normal intelligence.[3]  Infections, such as meningitis, may develop and could also affect the outcome.  

Following treatment, individuals with small meningoencephaloceles and no other brain abnormalities may survive and may not have major disabilities, while those with large and/or severe meningoencephaloceles have lower survival or may continue to suffer from intellectual and physical disabilities.
Last updated: 8/27/2014

  • Sitthiporn Agthong and Viroj Wiwanitkit. Encephalomeningocele cases over 10 years in Thailand: a case series. BMC Neurology. 2002; 2: Accessed 9/19/2011.
  • Kiymaz N, Yilmaz N, Demir I, Keskin S. Prognostic Factors in Patients with Occipital Encephalocele. Pediatric neurosurgery 2010. 2010; 46(1):6-11.
  • Mealey J, Dzenitis AJ, Hockey AA. The prognosis of encephaloceles. Journal of Neurosurgery. 1970; 32(2):209-218. Accessed 8/27/2014.
  • Hoving EW. Nasal encephaloceles. Childs Nerv Syst. November 2000; 16(10-11):702-706.
Other Names for this Disease
  • Encephalomeningocele
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.