Maternal Antibodies Target Fetus’ Brain and Cause Autism

Maternal antibodies can target proteins in fetus' brain that can eventually lead to autism, a latest study reveals.

The study conducted by University of California, Davis's MIND Institute found a maternal autoantibody that alters brain development in fetus that results in autism or Autism Spectrum Disorder (ASD).

The highly specific immunoglobulin-G (IgG) autoantibodies cross the placenta during pregnancy to impact fetal brain development and result in a form of autism that is called maternal antibody-related (MAR) autism. This could represent as much as 23 percent of all autism cases, researchers said in a news release.

For the study, the researchers exposed a group of pregnant female monkeys to immunoglobulin-G (IgG) purified from mothers of children with autism - IgG-ASD. Another group of pregnant female monkeys received IgG antibodies from the mothers of healthy children and the third group included untreated animals that did not receive antibodies.

The researchers then studied the behavioral development and over time conducted longitudinal magnetic resonance imaging (MRI) of the brain development for the first two years of the baby monkeys.

"The offspring of IgG-ASD antibody treated mothers consistently deviated from species-typical behavioral development of young rhesus monkeys," study lead author Mellissa D Bauman said. During the initial development stages, the monkey mothers treated with IgG-ASD antibodies showed protection toward their babies.

The researchers observed that the IgG-ASD treated mothers frequently approached and contacted their infants and remained in close proximity to them. "The heightened protectiveness of the monkey mother's was observed only when other animals were present, suggesting that the mothers perceived a greater risk to their IgG-ASD treated infants," Bauman said.

The IgG-ASD treated offsprings showed symptoms of autism. The researchers tested behavioral patterns of the baby monkeys in cages. The IgG-ASD monkeys spent an average of three seconds with other monkeys and returned to their empty cages. They also avoided companionship.

David Amaral, research director of the MIND Institute and senior author of the paper said that "much research remains ahead of us to identify the mechanisms by which the antibodies affect brain development and behavior. But, this program of research is very exciting, because it opens pathways to potentially predicting and preventing some portion of future autism cases."