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UC Davis MIND Institute

UC Davis MIND Institute

Recent Infant Sibling Study Findings

Over 200 children participated in the first phase of the study between 2003 and 2008. We have found several important results:

  • Previous estimates of second child autism risk, based on data from the 1980’s, were 3 – 5%. Our data (and that of others across the country) suggest that the risk may be as much as four times higher than initially thought, between 15 and 20%.
  • Up to a third of younger siblings of children with autism may have speech delays and other communication delays, such as later pointing, although they do not develop autism.
  • Two red flags for autism as young as 12 months of age are failure to respond consistently to name and unusual use of objects, such as staring at them for prolonged periods, rotating them, or spinning them.
  • Surprisingly, very few children who develop autism are identifiable at 6 months of age. In our study, most of these infants engage warmly with others, smile at people, vocalize to others, and make good eye contact at 6 months. However these skills decreased between 6 and 18 months as signs of autism slowly emerged. Our current focus is on trying to discover risk markers at 6 months of age that might predict which children will begin to show this decline into autism.