Which are the causes of Spina bifida?

Spina bifida is a complex neural tube defect caused by a combination of genetic, nutritional, and environmental factors that interfere with the closure of the spine during the first month of fetal development. While the exact cause is not fully understood, it is widely recognized as a multifactorial condition rather than one linked to a single gene or event.

What causes Spina bifida to develop?

The development of Spina bifida occurs when the neural tube—the structure that eventually becomes the brain and spinal cord—fails to close completely. This usually happens within the first 28 days of pregnancy. Think of the neural tube like a zipper; if the zipper doesn't close all the way, the underlying structures remain exposed. Research indicates that Spina bifida arises from a complex interplay between a person’s genetic predisposition and their environment.

Are there specific genetic or environmental risk factors?

While Spina bifida is not typically caused by a single, simple genetic mutation, it is known to run in families. If a parent has had one child with Spina bifida, the risk for subsequent pregnancies increases to approximately 3%. Key risk factors that have been scientifically validated include:

• Folate Deficiency: Low levels of folic acid (Vitamin B9) in the mother’s system before and during early pregnancy are the most significant modifiable risk factor.


• Maternal Health Conditions: Pre-existing diabetes or obesity can increase the likelihood of a child being born with Spina bifida.


• Medications: Certain anti-seizure medications, such as valproic acid, are known to interfere with folate metabolism and increase risk.


• Hyperthermia: Exposure to high temperatures, such as fevers or hot tubs, in early pregnancy has been linked to neural tube defects.

Is the etiology of Spina bifida fully understood?

Current research continues to explore the "missing heritability" of Spina bifida. Scientists are investigating how gene-environment interactions, such as how specific maternal diets interact with a fetus's genetic makeup, influence neural tube closure. While we have made significant progress in prevention through folic acid fortification, Spina bifida remains a subject of active study to identify further preventative strategies.

Next steps

• Consult with a genetic counselor to discuss family history and recurrence risks.


• Speak with an OB/GYN about prenatal folic acid supplementation if you are planning a pregnancy.


• Connect with the 207 members on DiseaseMaps.org to share experiences and learn about ongoing research.

Medical disclaimer: This information is for educational purposes and should not replace professional medical advice, diagnosis, or treatment.

References

• National Institute of Neurological Disorders and Stroke (NINDS) - Spina Bifida Information Page


• NIH Genetic and Rare Diseases Information Center (GARD)


• Orphanet: Neural tube defect, isolated


• Spina Bifida Association (SBA)