"Parents of children with autism take note. It may be possible to predict autism in infants as young as  months who have older siblings with the disorder according to a new study by a national network of researchers. Infants in such families are at increased risk of developing autism which is typically diagnosed when a child is  to yearsold and develops symptoms such as challenges with social skills repetitive behaviors delayed speech or nonverbal communication. Researchers used magnetic resonance imaging  or MRI  to scan the brains of  infants when they were  months  months and  months old. Twothirds of the infants were high risk having an older sibling with autism. The scans showed that  percent of highrisk toddlers diagnosed with autism at age  had an elevated amount of cerebrospinal fluid around their brains at  and  months compared to toddlers who were not diagnosed with autism. Cerebrospinal fluid is a clear colorless liquid that bathes the brain and spine. This excess fluid could possibly be an early biological marker for autism said Mark Shen the lead author of the article published in Biological Psychiatry and a postdoctoral fellow at the University of North Carolinas Carolina Institute for Developmental Disabilities. Additional studies are needed to confirm the finding he said. Such a marker would allow doctors to identify infants at high risk of developing autism before symptoms are present. The earlier we can get biological markers for autism the earlier intervention can be initiated and the greater the chance of better outcomes  said David Kennedy Ph.D. codirector of the Child and Adolescent NeuroDevelopment Initiative at the University of Massachusetts Medical School. Typically therapists work with children and parents to improve eye contact social interactions and communication skills. The study results are very exciting said Dr. Adriania Di Martino a professor of child and adolescent psychiatry at NYU Medical School. Excess brain fluid may be more than an early marker for autism Di Martino said. It may also be a mechanism in the development of autism and it opens up new possibilities for research she said. You can start thinking about conditions that might lead to increased cerebrospinal fluid. Shen and his colleagues are already looking for genes associated with excess brain fluid. Normally the liquid refreshed four times a day washes away byproducts that build up in the brain. But if the fluid is not flowing properly these byproducts hang around and cause inflammation which could hamper brain development and lead to autism said Shen. Completely different mechanisms may be at work for kids without an older sibling with autism said Shen and Dimartino. More studies are needed they said. Parents with children with autism should not rush to their pediatrician demanding brain MRIs for younger siblings Shen said. We wouldnt recommend that every highrisk infant get an MRI until we know that the accuracy can be improved closer to the  percent range from the current  percent Shen told TODAY. He and his colleagues are working on improving accuracy by combining their brain fluid findings with other recent research. In addition to flushing out the brains garbage brain fluid also delivers signals to the brain that tell it how and when to grow. In a study published last month in Nature http  percent of infants diagnosed with autism as toddlers had an increased rate of growth in the surface area of their brains in their first year compared to toddlers who were not diagnosed with autism. Were going to combine those two markers to see if we can improve the prediction closer to the  percent range where it could be really clinically useful said Shen. About  in  children develop autism in the United States according to the Centers for Disease Control and Prevention But as many as  out of  infants with an older sibling with autism will develop the disorder said Di Martino."