Researchers from the UNC School of Medicine's Department of Psychiatry have discovered a significant link between infants with abnormally enlarged perivascular spaces in their brains and a higher risk of developing autism, according to a study published in JAMA Network Open.

The study focused on infants who were at an increased likelihood of developing autism due to having an older sibling with the condition. The researchers followed these infants from 6 to 24 months of age, before the age of autism diagnosis, and found that nearly half of the diagnosed autistic infants had enlarged perivascular spaces by 24 months.

Enlarged perivascular spaces were observed in infants as early as 12 months, indicating that these brain abnormalities could potentially serve as an early marker for autism. The researchers found that infants with enlarged perivascular spaces had a 2.2 times greater chance of developing autism compared to infants with the same genetic risk.

The study also highlighted the crucial role of cerebrospinal fluid (CSF) in maintaining brain health and clearing neuroinflammatory proteins. CSF circulates through perivascular spaces, flushing out potentially harmful substances and waste. Disrupted CSF circulation can lead to neurological dysfunction, cognitive decline, or developmental delays.

The researchers further hypothesized that CSF abnormalities in infancy could be linked to sleep problems later in life. Their analysis revealed that children with enlarged perivascular spaces at two years of age had higher rates of sleep disturbances during school age.

"These findings suggest that perivascular spaces not only have an effect early in life but can also have long-term effects," said Dea Garic, assistant professor of psychiatry and a member of the Carolina Institute for Developmental Disabilities (CIDD), who was the first author of the paper.

The research, conducted in collaboration with the Infant Brain Imaging Study (IBIS), involved analyzing 870 MRIs obtained from babies during natural sleep at six, 12, and 24 months of age. The findings challenge the notion that enlarged perivascular spaces are only clinically relevant in older adults with neurodegenerative disorders, such as dementia.

Moving forward, the researchers plan to further investigate CSF flow and its impact on brain development. They also aim to quantify the size of perivascular spaces and analyze the severity of behavioral outcomes associated with these brain abnormalities. Additionally, the team plans to extend their research to neurogenetic syndromes associated with autism.

The study was supported by funding from the National Institutes of Health, including the Eunice Kennedy Shriver National Institute of Child Health and Human Development, the National Institute of Mental Health, and the National Institute of Environmental Health Sciences, as well as the Simons Foundation.

This research provides new insights into early markers of autism, emphasizing the importance of monitoring brain health in infants and the potential for early intervention strategies. By identifying enlarged perivascular spaces as a potential risk factor for autism, there may be opportunities to develop targeted therapies and support systems for affected individuals.