A new study led by UC Davis MIND Institute researchers found a distinct DNA methylation signature in the cord blood of newborns who were eventually diagnosed with autism spectrum disorder (ASD). This signature mark spanned DNA regions and genes linked to early fetal neurodevelopment. The findings may hold clues for early diagnosis and intervention.
The researchers studied the development of 152 children born to mothers enrolled in the MARBLES and EARLI studies. These mothers had at least one older child with autism and were considered at high risk of having another child with ASD. When these children were born, the mothers’ umbilical cord blood samples were preserved for analysis. At 36 months, these children got diagnostic and developmental assessments. Based on these, the researchers grouped the children under “typically developing” (TD) or “with ASD.”
The researchers also analyzed the umbilical cord blood samples taken at birth from the delivering mothers. They performed whole-genome sequencing of these blood samples to identify an epigenomic signature or mark of ASD at birth. They were checking for any patterns of DNA-epigenome binding that could predict future ASD diagnosis.
The researchers identified DMRs stratified by sex that discriminated ASD from TD cord blood samples in discovery and replication sets. They found that seven regions in males and 31 in females replicated, and 537 DMR genes in males and 1762 DMR genes in females replicated by gene association. These DMRs identified in cord blood overlapped with binding sites relevant to fetal brain development. They showed brain and embryonic expression and X chromosome location and matched with prior epigenetic studies of ASD.
“Findings from our study provide key insights for early diagnosis and intervention,” LaSalle said. “We were impressed by the ability of cord blood to reveal insights into genes and pathways relevant to the fetal brain.”
The researchers pointed out that these results will require further replication before being used diagnostically. Their study serves as an important proof of principle that the cord blood methylome is informative about future ASD risk.