In most cases, autism can’t be diagnosed until children are two years old, but sometimes signs of the condition appear earlier. Usually, babies that have otherwise progressed normally will start showing subtle changes in behavior: difficulty focusing or speaking with others, or trouble pointing at objects. The trouble is, it’s hard to definitively say whether these patterns are reason for concern. Because doctors can’t confirm a diagnosis before a child is 24 months old, parents may be left feeling anxious without answers.
However, new research (paywall) led by a team of scientists at the University of North Carolina-Chapel Hill suggests there may be a biomarker that would enable doctors to give parents a clear answer about their child’s condition (or lack thereof) and intervene with therapies early on if necessary. They found that faster-than-typical brain growth during infancy—a pattern that can be spotted easily using medical imaging—can predict whether or not a child will develop autism spectrum disorder (ASD) later on.
The UNC scientists took brain scans of over 106 infants who were considered high-risk for developing autism because they had siblings with ASD and of 42 babies without an immediate family member with autism. The researchers took images of the all the babies’ brains at six, 12, and 24 months.
Fifteen of the babies were diagnosed with ASD by their second birthday. The research team went back and looked at the brain scans, and noticed the brains of the babies with ASD developed differently at two stages compared to the other infants’ brains. Between six and 12 months, the outer layer of the front of the brain was slightly larger. Over the next 12 months, their brains continued to grow slightly larger than their peers in general. It appears that, for reasons scientists don’t yet understand, this early growth in the front of the brain is the beginning of a pattern that leads to bigger brains overall. Larger brain size has been associated with ASD.
This study, published in Nature, also backs up previous work in mice, which showed that having too many cells in the forefront of the brain is correlated to behaviors similar to humans with autism.
Researchers still aren’t sure what causes this neurological development, but being able to spot it early on would enable doctors to give parents of high-risk children an earlier diagnosis and intervention plan. The diagnostic method is far from ready to apply in clinics, though; it needs to be confirmed in much larger studies.