WHAT'S KNOWN ON THIS SUBJECT:The sibling recurrence risk of autism has been estimated to be between 3% and 10%. Previous research was affected by small samples and selection, stoppage, and reporting limitations. Updated estimates of recurrence risk are needed. WHAT THIS STUDY ADDS:Studying a large sample and using a prospective longitudinal design, this study demonstrated that the sibling recurrence risk of autism spectrum disorder is substantially higher than previous estimates. This elevated risk has important implications for infant screening and genetic counseling. abstract OBJECTIVE: The recurrence risk of autism spectrum disorders (ASD) is estimated to be between 3% and 10%, but previous research was limited by small sample sizes and biases related to ascertainment, reporting, and stoppage factors. This study used prospective methods to obtain an updated estimate of sibling recurrence risk for ASD. METHODS:A prospective longitudinal study of infants at risk for ASD was conducted by a multisite international network, the Baby Siblings Research Consortium. Infants (n ϭ 664) with an older biological sibling with ASD were followed from early in life to 36 months, when they were classified as having or not having ASD. An ASD classification required surpassing the cutoff of the Autism Diagnostic Observation Schedule and receiving a clinical diagnosis from an expert clinician. RESULTS:A total of 18.7% of the infants developed ASD. Infant gender and the presence of Ͼ1 older affected sibling were significant predictors of ASD outcome, and there was an almost threefold increase in risk for male subjects and an additional twofold increase in risk if there was Ͼ1 older affected sibling. The age of the infant at study enrollment, the gender and functioning level of the infant's older sibling, and other demographic factors did not predict ASD outcome. CONCLUSIONS:The sibling recurrence rate of ASD is higher than suggested by previous estimates. The size of the current sample and prospective nature of data collection minimized many limitations of previous studies of sibling recurrence. Clinical implications, including genetic counseling, are discussed. Pediatrics 2011;128:e488-e495 AUTHORS:

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Objective-To examine prospectively the emergence of behavioral signs of autism in the first years of life in infants at low and high risk for autism.Method-A prospective longitudinal design was used to compare 25 infants later diagnosed with an autism spectrum disorder (ASD) with 25 gender-matched low-risk children later determined to have typical development. Participants were evaluated at 6, 12, 18, 24, and 36 months of age.Correspondence to: Dr. Ozonoff, M.I.N.D. Institute, University of California Davis Health System, 2825 50 th Street, Sacramento CA 95817; sally.ozonoff@ucdmc.ucdavis.edu. Disclosure: Drs. Ozonoff, Iosif, Cook, Hutman, Rogers, Rozga, Sigman, Steinfeld, and Young, and Mr. Baguio, Ms. Hill, and Ms. Sangha report no biomedical financial interests or potential conflicts of interest.Editorial support for the preparation of this article was provided by Diane Larzelere, UC Davis. NIH Public AccessAuthor Manuscript J Am Acad Child Adolesc Psychiatry. Author manuscript; available in PMC 2010 August 17. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author ManuscriptFrequencies of gaze to faces, social smiles, and directed vocalizations were coded from video and rated by examiners.Results-The frequency of gaze to faces, shared smiles, and vocalizations to others were highly comparable between groups at 6 months of age, but significantly declining trajectories over time were apparent in the group later diagnosed with ASD. Group differences were significant by 12 months of age on most variables. Although repeated evaluation documented loss of skills in most infants with ASD, most parents did not report a regression in their child's development.Conclusions-These results suggest that behavioral signs of autism are not present at birth, as once suggested by Kanner, but emerge over time through a process of diminishment of key social communication behaviors. More children may present with a regressive course than previously thought, but parent report methods do not capture this phenomenon well. Implications for onset classification systems and clinical screening are also discussed. KeywordsAutism; Onset; Infancy; Regression This study examined when and how behavioral signs of autism spectrum disorders (ASD) emerge in the first years of life. Most previous investigations of this topic have been retrospective, relying on parent report of earlier development or analysis of home videotape of infants later diagnosed with ASD. The existing literature suggests that behavioral signs of autism emerge in two different patterns, an early onset and a regressive course.Retrospective studies have demonstrated that children with early-onset ASD differ from agematched children with delayed and typical development in orienting to name, gaze to faces, joint attention, and affect sharing. [1][2][3][4][5][6] Differences are most evident in the second year of life 7 but some studies have detected signs of ASD before the first birthday. 1,5,8 This early onset pattern is thought to occur in the majority of indiv...

The neurodiversity movement challenges the medical model's interest in causation and cure, celebrating autism as an inseparable aspect of identity. Using an online survey, we examined the perceived opposition between the medical model and the neurodiversity movement by assessing conceptions of autism and neurodiversity among people with different relations to autism. Participants (N = 657) included autistic people, relatives and friends of autistic people, and people with no specified relation to autism. Self-identification as autistic and neurodiversity awareness were associated with viewing autism as a positive identity that needs no cure, suggesting core differences between the medical model and the neurodiversity movement. Nevertheless, results suggested substantial overlap between these approaches to autism. Recognition of the negative aspects of autism and endorsement of parenting practices that celebrate and ameliorate but do not eliminate autism did not differ based on relation to autism or awareness of neurodiversity. These findings suggest a deficit-as-difference conception of autism wherein neurological conditions may represent equally valid pathways within human diversity. Potential areas of common ground in research and practice regarding autism are discussed.