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DEE1 is caused by mutations in the ARX gene. The protein produced from this gene plays a role in the normal functioning of the brain by regulating other genes that contribute to brain development. Research suggests that mutations in the ARX gene reduce the amount or function of the ARX protein. A shortage of ARX function is thought to disrupt normal brain development, leading to seizures and intellectual disability.

It is likely that mutations in other genes that have not been identified cause rare cases of DEE1. Infantile spasms can also have nongenetic causes, such as brain malformations, other disorders that affect brain function, or brain damage. In addition, changes in genes that are not located on the X chromosome cause infantile spasms in rare cases.

MedlinePlus Genetics: Causes

","key":"forms","title":"What causes Developmental and epileptic encephalopathy 1?"},{"bodyHtml":"

Most babies with DEE1 have characteristic results on an electroencephalogram (EEG), a test used to measure the electrical activity of the brain. The EEG of these individuals typically shows an irregular pattern known as hypsarrhythmia, and this finding can help differentiate infantile spasms from other types of seizures.

Early in life, babies with DEE1 stop developing normally and begin to lose skills they have acquired (developmental regression), such as sitting, rolling over, and babbling. Most affected individuals also have intellectual disability throughout their lives.

Source: MedlinePlus Genetics

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