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spina bifida

Tuesday 31 August 2004

Definition: Spina bifida (SB) is one of the neural tube defects (NTDs) caused by the failure of the fetus’s spine to close properly during the first month of pregnancy.

The most common types of SB are:

- spina bifida occulta (one or more vertebrae are malformed and covered by a layer of skin)
- meningocele (the spinal cord develops normally but the meninges protrude from a spinal opening)
- myelomeningocele (the spinal cord and the meninges protrude from an opening in the spine)
- spina bifida aperta
- spina bifida cystica


- cervical spina bifida
- thoracic spina bifida
- lombar spina bifida
- sacral spina bifida


- variation in genes that are involved in the folate-homocysteine metabolic pathway

  • variants in gene coding for methylenetetrahydrofolate reductase (MTHFR)
  • variants in gene coding for the trifunctional enzyme methylenetetrahydrofolate dehydrogenase/methenyltetrahydrofolate cyclohydrolase/formyltetrahydrofolate synthetase (MTHFD1) (12384833)
  • variants in genes involved in homocysteine remethylation/methionine biosynthesis
    • methionine synthase (MTR)
    • methionine synthase reductase (MTRR)

- Loci

  • 1q43
  • 5p15.3-p15.2

- X-linked spina bifida (MIM.300293)

  • lumbosacral spina bifida and myeloschisis
  • de novo/autosomal translocation, t(X;22)(q27;q12.1)


- encephalocele (9182784)
- anencephaly (anencephaly-spina bifida association)

  • X-linked anencephaly-spina bifida association (MIM.301410)

- sacral agenesis
- neural crest anomalies (8.5%) (10508971)

- association split hand-onbstructive uropathy- spina bifida and diaphragmatic defects (MIM.183802) (3308683)

- abdominal wall defects

  • gastroschisis
    • spina bifida-gastroschisis association (hp7883)
  • omphalocele
    • association gonadal agenesis, encephalocele, spina bifida, omphalocele (GAESBO) (9182784)

- hypospadias (7977461)
- multiple pilomatricomas (15804314)

Etiological forms

- non-syndromal spina bifida

  • non-syndromal sporadic spina bifida
  • non-syndromal familial spina bifida

- syndromal spina bifida

See also

- spinal malformations
- neural tube defects
- myelomeningocele


- De Marco P, Merello E, Mascelli S, Capra V. Current perspectives on the genetic causes of neural tube defects. Neurogenetics. 2006 Nov;7(4):201-21. PMID: 16941185