A new study has revealed differences in the brains of infants, as young as six months, who later develop autism compared to those who do not. The study looked at children, who were considered high-risk because they have older siblings with the disorder. The differences were found in the development of white matter fiber tracts, which were measured by fractional anisotropy (FA), through analyzing the movement of water molecules through brain tissue. In 12 of the 15 tracts, pathways that connect brain regions, the infants who later developed autism showed elevated FA at six months old, then began to develop more slowly over time, so that by 24 months the infants with autism had lower FA values than those who did not. This finding could eventually lead to the discovery of a biomarker for autism. “This research raises the possibility that we might be able to intervene even before a child is six months old, to blunt or prevent the development of some autism symptoms,” said Sarah Paterson, who worked on the study.