title: The power and promise of identifying autism early: insights from the search for clinical and biological markers.
abstract: BACKGROUND
  The biological changes that lead to autism likely occur during prenatal life. Although earlier identification of the disorder has occurred within the past decade, the mean age of diagnosis is still not made before a mean age of 3 years. This is because autism remains a behaviorally defined disorder, placing limits on the age at which a confident diagnosis can be made. The study of the biological basis of autism prior to age 3 is essential and can most directly be achieved with prospective research designs.
  
  
  METHODS
  The literature on the early identification of autism is discussed, including the timescale for the onset of social symptoms. Also discussed is a new method for the prospective study of autism called the "1-Year Well-Baby Check-Up Approach," which allows for the prospective study of the disorder in simplex families with infants as young as 12 months of age.
  
  
  RESULTS
  Although likely present at subtle, subclinical levels, early social abnormalities are not clearly detectable prior to 12 months in age in infants later diagnosed as having autism spectrum disorder.
  
  
  CONCLUSIONS
  Using the 1-Year Well-Baby Check-Up Approach or other prospective design, examining early biomarkers related to early brain overgrowth, cerebellar development, gene expression patterns and immune system function may be key to early diagnosis efforts under 3 years. We also note the importance of comparing and contrasting the early "signature" of autism in children from singleton versus multiplex families, which may be etiologically distinct.
authors.affiliation: Department of Neurosciences, University of California, San Diego, San Diego, CA 92037, USA. kpierce@ucsd.edu
authors.forename: Karen
authors.initials: K
authors.lastname: Pierce
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Glatt
authors.forename: Gregory S
authors.initials: GS
authors.lastname: Liptak
authors.forename: Laura Lee
authors.initials: LL
authors.lastname: McIntyre
mesh_terms: D001321:Autistic Disorder / Q000097:blood / Q000175:diagnosis* / Q000235:genetics; D015415:Biomarkers / Q000097:blood; D001921:Brain / Q000254:growth & development; D002652:Child Behavior; D002675:Child, Preschool; D015870:Gene Expression / Q000235:genetics; D005819:Genetic Markers / Q000235:genetics; D006801:Humans; D007223:Infant; D008403:Mass Screening / Q000379:methods; D011446:Prospective Studies; D012919:Social Behavior
chemical_list: D015415:Biomarkers; D005819:Genetic Markers