A routine blood draw taken in the final weeks of pregnancy may one day carry hints about whether a child will go on to be diagnosed with autism, according to a new study that researchers describe as an early but meaningful step toward understanding the disorder’s biological origins before birth.
The research, published in the journal Communications Biology, examined cell-free DNA — fragments of genetic material, much of it shed from the placenta, that circulate in a pregnant woman’s bloodstream.
Scientists at University of California at Davis and partner institutions sequenced the full methylome of samples collected from 51 pregnancies between 36 and 41 weeks’ gestation, mapping the chemical tags that turn genes on and off without altering the DNA sequence itself.
Specific methylation patterns lined up with which children later received an autism diagnosis by age three, and many of those same patterns overlapped with changes tied to maternal obesity, a long-suspected but poorly explained risk factor for the disorder.
In other words, a single vial of a pregnant woman’s blood in her final trimester may already contain faint chemical footprints of how her baby’s brain is developing, footprints that, in this study, showed up more often in children later diagnosed with autism.
A professor and molecular epidemiologist at UC Davis, Rebecca Schmidt, tells me that the findings offer a preliminary but real signal.
“There might be markers associated with the child’s future neurodevelopmental outcomes, like autism, that can be found in maternal blood during late pregnancy,” Ms. Schmidt said.
So, what does a finding like this actually change for doctors, and for the families waiting years for answers?
