Researchers in autism spectrum disorders have discovered a promising new way to detect prenatal exposures that could increase risk for autism even years after the exposures occurred.
The researchers in their study showed that a chemical signature of prenatal exposure to cigarette smoke can be detected in the blood of pre-schoolers. Weather smoking during pregnancy contributes to autism is not a known fact yet. But, since the mother can say whether or not she smoked during her pregnancy, a clear chemical signature of prenatal exposure persisted into childhood could still be seen.
The next step is to look for markers for less-obvious toxic exposures, which are suspected to increase the risk of autism spectrum. Among these include exposure to air pollution, pesticides, plasticizers and maternal inflammation during a woman’s pregnancy.
A study which was led by Daniele Fallin and Christine Ladd-Acosta, appeared in the journal Environmental Research a couple of weeks ago.
She is the director of the Bloomberg School’s Wendy Klag Center for Autism & Developmental Disabilities at Johns Hopkins University.
More to the point, Fallin’s team is looking at so-called epigenetic markers. These are chemical tags which sit on top a gene’s DNA. These help control where and when the gene is active.
This epigenetic control of gene activity is especially crucial for guiding early brain development. Chemical exposures, infection and other types of stresses can change epigenetics. This in turn can alter gene activity in important and permanent ways.
Across the whole study, the researchers performed whole genome epigenetic analysis on the blood of children, ages 3 to 5. It total there were 531 from six sites across America. The children’s mothers were asked about smoking during pregnancy.
The next step was to analyze epigenetic patterns (methylation) at 26 locations across the children’s genomes. They were able to identify which mothers smoked during pregnancy with 81 percent accuracy based on all of the available data.
There have been other researchers that had previously identified these epigenetic signatures. They found them in infant cord blood from prenatal pregnancies. This new study however, is the first to show that the tell-tale chemical evidence persists to at least the age of about 5.
It is Fallins hope this area of research has a much broader reach. When a prenatal mother smokes, she says it is quite easy to determine whether someone was exposed prenatally. All you have to do is ask the mother or ask someone whether the mother smoked while she was pregnant. However, when there is exposures to other toxins, it is more difficult to tease out. The biggest problem is that the mother may not know whether she was exposed or not.