A genetic abnormality in the brain could be integral to Down syndrome, researchers say in a finding that could point to new treatment options for those with the chromosomal disorder.

Though it’s long been thought that many biological changes associated with Down syndrome occur prenatally, the study published online this week in the journal Neuron suggests that alterations in the brain continue to present throughout life.

For the study, researchers looked at gene expression in the brains of individuals with and without Down syndrome at various ages – ranging from mid-fetal development to adulthood. They found that the establishment of white matter, which insulates nerve fibers in the brain, changes as people with Down syndrome age.

“This discovery of the genetic changes that alter communication within the brain uncovered a completely new target for therapies in the brains of people with DS,” said Tarik Haydar, an associate professor of anatomy and neurobiology at Boston University School of Medicine who worked on the study.

Though the hallmark of Down syndrome is having an extra twenty-first chromosome, the researchers found that more than 1,300 genes were disrupted in those with the condition, nearly all of which were outside of that chromosome, indicating that the effects are widespread.

Fluorescent images of nerve connections in the brain of a typically-developing individual, left, compared to a person with Down syndrome. (Yale University)

Specifically, researchers said defective myelination could be at least partly responsible for intellectual disability in those with Down syndrome. Myelin coats nerve fibers and allows for transmission of nerve impulses.

Myelin-regenerating drugs are already available to treat other conditions like multiple sclerosis and such treatments may benefit people with Down syndrome, the study authors indicated.

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