Gut Bacteria May Influence Early Brain Development and Neurodevelopmental Risk

Epigenetic changes at birth may influence gut bacteria development during a baby's first year of life. These interactions are linked to early signs of autism spectrum disorder (ASD) and Attention-Deficit/Hyperactivity Disorder (ADHD) by age three. The findings, published in *Cell Press Blue*, suggest a complex relationship between a baby's genes and their gut microbes.

Researchers analyzed DNA methylation patterns from umbilical cord blood of 571 infants. They combined this data with gut microbiome samples from 969 infants at two, six, and twelve months of age. Parental microbiome samples were also collected during the third trimester of pregnancy. At 36 months, children's neurodevelopment was assessed using a behavioral questionnaire.

Epigenetic patterns at birth were associated with factors like delivery method, pregnancy length, and maternal allergies. The development of the infant microbiome was influenced by delivery method, antibiotic exposure, and breastfeeding. Infants delivered by Caesarean section showed distinct DNA methylation patterns in genes related to immune function and brain development.

The study found that epigenetic patterns at birth affected how the gut microbiome evolved. Infants with higher DNA methylation in certain immune-related genes developed less diverse gut microbiomes by twelve months. These genes help the body recognize and respond to pathogens. This suggests that biological signals present at birth guide the gut microbial community's development.

Specific combinations of epigenetic markers and gut microbes were associated with signs of ASD and ADHD. However, certain bacteria appeared to offer protection. Children with epigenetic patterns linked to ASD were less likely to show signs if they acquired *Lachnospira pectinoschiza* during infancy. Similarly, children with ADHD-associated epigenetic patterns were less likely to show signs if they acquired *Parabacteroides distasonis* in their first year.

Researchers continue to follow the children to understand long-term health impacts. Laboratory studies are needed to confirm the observed relationships. The goal is to develop safe interventions, such as specific probiotics, to support a healthy gut microbiome and potentially reduce neurodevelopmental challenges.