Causes of autism remain largely a mystery, but Johns Hopkins researchers have found another likely culprit.
In rare cases, brain cells from a fetus may migrate into the mother, triggering an immune reaction linked to autism, the Hopkins researchers reported.
“Mothers might get exposed to fetal tissue and produce
antibodies,” said Dr. Harvey Singer, a Johns Hopkins Children?s Center investigator in Baltimore City.
Those antibodies could cross the placenta and attack the developing child?s brain during pregnancy, said Singer, whose work is published in the February edition of the Journal of Neuroimmunology.
Researchers compared the antibody-brain interaction in samples from 100 mothers of autistic children and 100 mothers of children without autism.
The research revealed stronger reactions between antibodies and brain protein samples in about 40 percent of the mothers of autistic children.
And the presence of maternal antibodies was associated with developmental regression ? increasingly immature behaviors that are a hallmark of
autism.
Today, one in 150 individuals is diagnosed with autism, according to the national organization Autism Speaks.
But doctors have little understanding of what causes autism.
It occurs in all racial, ethnic and social groups and is four times more likely to strike boys than girls.
The disorder impairs a person?s ability to communicate and relate to others.
It is also associated with inflexible routines and repetitive behaviors, such as obsessively arranging objects.
In about 10 percent of cases, genetics are a factor, Singer said, but the rest remain a mystery.
While Singer?s findings suggest a link between autism and fetal brain antibodies, further studies are needed to confirm that particular antibodies do indeed cross the placenta and cause damage to the fetal brain, he said.
“The mere fact that a pregnant woman has antibodies against the fetal brain doesn?t mean she will have an autistic child,” Singer said.
“Autism is a complex condition, and one likely caused by the interplay of immune, genetic and environmental factors.”
