Summary: A new study reveals how maternal obesity before pregnancy can program autism-related behaviors in offspring through lasting epigenetic changes in egg cells. Using IVF and embryo transfer in mice, researchers isolated the pre-conception effects, finding altered DNA methylation patterns that disrupted genes such as Homer1.
In male offspring, these changes led to impaired social behaviors and repetitive grooming, consistent with autism spectrum disorder. The findings underscore the importance of maternal health even before conception and may pave the way for interventions that start well before pregnancy.
Key Facts
Epigenetic Link: Pre-pregnancy obesity caused DNA methylation changes in eggs, altering neurodevelopmental gene expression in offspring.Autism-Related Behaviors: Male offspring showed impaired social behaviors and repetitive grooming linked to Homer1a overexpression.Isolated Effect: IVF and embryo transfer models confirmed changes occurred before conception, not during pregnancy.
Source: University of Hawaii
In a groundbreaking study conducted at the University of Hawaiʻi at Mānoa, researchers from the John A. Burns School of Medicine (JABSOM) have uncovered a mechanistic link between maternal obesity prior to pregnancy and autism-related behavioral outcomes in offspring.
The study, led by Professors Dr. Alika K. Maunakea and Dr. Monika Ward from the Department of Anatomy, Biochemistry & Physiology and the Yanagimachi Institute for Biogenesis Research (YIBR), sheds new light on how maternal health even before conception can program long-term neurodevelopmental trajectories in children.
“This work highlights how a mother’s health prior to pregnancy—not just during gestation—can shape her child’s brain development in profound ways,” said Dr. Maunakea. Credit: Neuroscience News
The researchers demonstrated that obesity-induced changes in the mother’s metabolic environment lead to lasting epigenetic alterations in oocytes—the precursors to eggs. These modifications, specifically changes in DNA methylation patterns, were carried into the developing embryos, ultimately disrupting the expression of critical neurodevelopmental genes such as Homer1.
In male offspring, the study found increased expression of the short Homer1a isoform, known to interfere with synaptic function, resulting in behaviors consistent with autism spectrum disorder (ASD).
“This work highlights how a mother’s health prior to pregnancy—not just during gestation—can shape her child’s brain development in profound ways,” said Dr. Maunakea. “We were surprised to find that even without direct maternal contact after conception, these epigenetic imprints from the egg carried enough weight to alter behavior.”
Utilizing an in vitro fertilization (IVF) and embryo transfer model, the team separated the effects of maternal obesity before conception from influences during pregnancy, enabling a more precise view of how early epigenetic programming unfolds.
Behavioral tests in adolescent male mice revealed impaired social behaviors and repetitive grooming patterns reminiscent of ASD, correlating with altered gene regulation in the cortex and hippocampus.
“This discovery exemplifies the core mission of the YIBR,” said Dr. Ward. “By leveraging our institute’s expertise in developmental biology, reproductive science, and epigenetics, we are beginning to understand how early-life programming can ripple through generations.”
The Yanagimachi Institute for Biogenesis Research, named after world-renowned fertility pioneer Dr. Ryuzo Yanagimachi, fosters interdisciplinary collaboration in reproductive and developmental biology.
This study, reflecting the synergy between Dr. Ward’s expertise in reproductive science and Dr. Maunakea’s research in neuroepigenetics, exemplifies the institute’s commitment to translational discoveries with long-term health implications.
With rising global rates of both obesity and ASD, these findings could open new paths for early interventions—potentially even before conception. The researchers hope future studies will explore therapeutic strategies that may reverse or mitigate these effects through nutritional or pharmacological means.
The study has been accepted for publication in Cells, a leading peer-reviewed journal, and represents a significant step forward in our understanding of how early life factors shape brain development.
About this genetics, obesity, and autism research news
Author: Matthew Campbell
Source: University of Hawaii
Contact: Matthew Campbell – University of Hawaii
Image: The image is credited to Neuroscience News
Original Research: Open access.
“Pre-Conception Maternal Obesity Confers Autism Spectrum Disorder-like Behaviors in Mice Offspring Through Neuroepigenetic Dysregulation” by Alika K. Maunakea et al. Cells
Abstract
Pre-Conception Maternal Obesity Confers Autism Spectrum Disorder-like Behaviors in Mice Offspring Through Neuroepigenetic Dysregulation
Autism spectrum disorder (ASD) is a complex neurodevelopmental condition with early-life origins. Maternal obesity has been associated with increased ASD risk, yet the mechanisms and timing of susceptibility remain unclear.
Using a mouse model combining in vitro fertilization (IVF) and embryo transfer, we separated the effects of pre-conception and gestational obesity.
We found that maternal high fat diet (HFD) exposure prior to conception alone was sufficient to induce ASD-like behaviors in male offspring—including altered vocalizations, reduced sociability, and increased repetitive grooming—without anxiety-related changes.
These phenotypes were absent in female offspring and those exposed only during gestation. Cortical transcriptome analysis revealed dysregulation and isoform shifts in genes implicated in ASD, including Homer1 and Zswim6.
Whole-genome bisulfite sequencing of hippocampal tissue showed hypomethylation of an alternative Homer1 promoter, correlating with increased expression of the short isoform Homer1a, which is known to disrupt synaptic scaffolding. This pattern was specific to mice with ASD-like behaviors.
Our findings show that pre-conceptional maternal obesity can lead to lasting, isoform-specific transcriptomic and epigenetic changes in the offspring’s brain.
These results underscore the importance of maternal health before pregnancy as a critical and modifiable factor in ASD risk.