What Causes Infantile Spasms?

Any condition that damages the brain can cause infantile spasms, also called West syndrome. Some of the causes happen before a baby is born (prenatal) and some happen after birth (postnatal).

The most common cause is an inherited condition called tuberous sclerosis complex. It makes noncancerous tumors grow in different body parts, like your baby’s brain, skin, kidneys, or other organs. If your baby has them, you might notice colorless bumps on her skin.

Genetic conditions like Down syndrome can cause these spasms, too. Or it could come from a non-inherited problem with your baby’s genes.

Other causes of West syndrome include:

  • Brain injury
  • Problems with the way the brain formed
  • Changes in brain structure
  • Lack of oxygen to the brain
  • Brain infections
  • Lesions on the brain
  • Bleeding inside the skull
  • Inflammation in the brain (encephalitis)
  • Metabolism disorders
  • Vitamin B deficiency

Sometimes doctors can’t find a cause for West syndrome. But there’s no evidence that it could be related to vaccinations or your baby’s sex.

WebMD Medical Reference Reviewed by Hansa D. Bhargava, MD on May 15, 2018



National Organization for Rare Disorders: “West syndrome.”

National Institutes of Health, Genetics Home Reference: “Tuberous sclerosis complex.”

Epilepsy Foundation: “Infantile Spasms (West’s Syndrome) and Tuberous Sclerosis Complex.”

National Institutes of Health National Center for Advancing Translational Sciences: “West syndrome.”

Medscape: “Infantile Spasm (West Syndrome).”

Nemours Foundation: “Infantile Spasms.”

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