Public release date: 11-Feb-2008
SACRAMENTO, Calif.) – New research from the UC Davis M.I.N.D. Institute and Center for Children’s Environmental Health has found that antibodies in the blood of mothers of children with autism bind to fetal brain cells, potentially interrupting healthy brain development. The study authors also found that the reaction was most common in mothers of children with the regressive form of autism, which occurs when a period of typical development is followed by loss of social and/or language skills. The findings, to be published in the March 2008 issue of Neurotoxicology, raise the possibility that the transfer of maternal antibodies during pregnancy is a risk factor for autism and, at some point, that a prenatal test and treatment could prevent the disorder for some children.
“While a growing body of research is dedicated to finding distinctions in the immune systems of children with autism, this is one of the first studies to identify immunological factors in mothers that could be linked to autism in the very earliest stages of life,” said Judy Van de Water, senior author of the study and professor of rheumatology, allergy and clinical immunology. “Our results should lead to more research on the prenatal environment and the onset of autism. We are also optimistic that in the future a prenatal test and therapeutic intervention preventing IgG exposure during pregnancy could protect some children from ever getting autism.”
We’re not entirely sure why the IgG response against fetal brain proteins was so specific for later onset autism,” said Van de Water. “It’s possible that early exposure to maternal antibodies sets in motion a biological path to autism with the behavioral outcomes not apparent until much later. It’s also possible that an environmental exposure sometime after birth could be required to set this process in motion. We are hopeful that this study will help build our understanding of the foundations of the regressive form of the disorder.”
Characteristic features of autism – social deficits, language impairments and limited, repetitive behaviors – are often clear early in an affected child’s life. Other children seem to progress normally until 12-to-24 months of age, when developmental milestones disappear. These distinct pathways have led clinicians to identify autism as one of two types – early onset or regressive – potentially with distinct causes and disease processes.
IgG antibodies are responsible for long-term immune system responses to infection, but they can also contribute to autoimmune diseases such as arthritis, multiple sclerosis and lupus. IgG also crosses the placenta in order to provide key immune system protectants to a growing fetus and newborn child, which is a key reason why Van de Water decided to investigate the role of IgG as a potential factor in autism.
Van de Water next wants to know if IgG in women during the time of their pregnancies produces the same response to fetal brain proteins. Women in the current study were two-to-five years beyond childbirth. She will now conduct the same study with women who are pregnant and already have a child with autism, because such women are much more likely to have another child with the disorder.