Although autism spectrum disorder (ASD) appears to have its neurobiologic origins in prenatal or early postnatal life, it is not usually diagnosed before a child is three years old. In fact, there are no clinical guidelines for detecting ASD before 30 months. Dr. Landa and her colleagues have begun a program of study to develop criteria for diagnosing ASD by 18 months. Their preliminary findings from an NIH-funded study to assess social, language, cognitive, motor, and adaptive development from 14 months to 30 or 36 months show promise in detecting ASD between 14 months and 18 months. In particular, they find that measures of joint attention, shared positive mood and imitation help predict ASD. The researchers plan to corroborate their findings by almost doubling their sample size, adding 108 more children to the 125 they've already assessed. Their study compares three groups of children: siblings of children with ASD who are at increased genetic risk for the disorder, late talkers with no family risk of autism, and children with no family risk for ASD. NIH is funding assessments of these children at 18 months and 30 months. This augmentation grant will allow the researchers to include assessments at 14, 24 and 36 months. These more frequent assessments will provide a clearer picture of when detectable symptoms of ASD begin to manifest and whether the diagnosis is stable through age three. The researchers expect to replicate their earlier findings that they can diagnose ASD in some children by 14 months but not in others until later and that some children may show signs of ASD at 14 months but not at 36 months. What this means for people with autism:Findings from this study will provide a concrete set of sensitive and specific criteria for diagnosing ASD in children between 14 and 18 months of age. These diagnostic criteria will provide clinicians with a research-based tool with which to assess the increasing number of children referred before age three for evaluation of possible ASD. Early diagnosis will in turn allow children to receive intervention at the earliest possible time.