Epigenetic changes present at birth can influence the development of an infant's gut microbiome during their first year, according to a study published on April 10 in Cell Press Blue. The research also found that specific epigenetic patterns and gut microbes were linked to signs of autism spectrum disorder (ASD) and Attention-Deficit/Hyperactivity Disorder (ADHD) in children at age three.
The findings are significant because they suggest a relationship between molecular switches that turn genes on or off—known as epigenetics—and the bacteria living in the gut, both of which play roles in neurodevelopment. Understanding these interactions could open new ways to support children's health.
"Certain bacteria seem to offer protection, which is exciting because it suggests there could be ways to support a child's development through diet or probiotics in the future," said Francis Ka Leung Chan, senior author and gastroenterologist at The Chinese University of Hong Kong. Co-senior author Hein Min Tun added, "We wanted to see how the epigenome and microbiome interact in early life and if their interaction could influence a child's risk of developing neurodevelopmental conditions like ASD and ADHD. We discovered a kind of conversation happening: a baby's epigenetic setting at birth can influence their risk for neurodevelopmental disorders, but the presence of certain 'good' bacteria in their gut can step in and modify the risk."
Researchers analyzed DNA methylation patterns from umbilical cord blood samples from 571 infants alongside gut microbiome data collected from 969 infants over their first year. They also assessed behavioral signs related to ASD and ADHD when children reached three years old using questionnaires. The study found that factors such as birth mode, gestational length, older siblings, maternal allergies, antibiotics use, breastfeeding practices, and Caesarean section influenced either an infant's epigenome or microbiome development.
Importantly, infants with higher rates of DNA methylation—a type of epigenetic change—in immune genes had less diverse gut microbiomes by one year old. Signs of ASD or ADHD were associated with particular combinations of these genetic markers and microbial species; however, some bacteria appeared protective: "infants with epigenetic patterns associated with ASD or ADHD were less likely to show signs if they acquired Lachnospira pectinoschiza and Parabacteroides distasonis respectively during their first year," according to the researchers.
Tun said: "The foundations for brain health are laid very early, even before birth... However we don't want people to think this means a child's developmental path is fixed at birth. These are complex conditions with many causes." First author Siew Chien Ng stated that further laboratory work is needed but hopes future interventions such as specific probiotics might help nurture healthy development.
