Can Asperger Syndrome Be Diagnosed at 26 Months Old? A Genetic High-Risk Single-Case Stndy

Asperger syndrome, a heritable condition entailing empathy deficits together with unusually narrow interests in individuals of normal or even above-average intelligence, was recognized only recently. Here we report the first-ever prospective study of a child bom to two adults with a formal diagnosis of Asperger syndrome. The child's parents are both scientists (a mathematician and a chemist). The aim of study 1 was to test if the child also developed Asperger syndrome, given the heritability of the condition, and if Asperger syndrome can be detected at 26 months. At 18 months, the child was given the Checklist for Autism in Toddlers, and at 26 months, she was assessed diagnostically for autism spectrum conditions using the Autism Diagnostic Interview-Revised and the Autism Diagnostic Observational Scale. The child failed the Checklist for Autism in Toddlers at 18 months and met the criteria for Asperger syndrome at 26 months. This single case is consistent with the hypersystemizing, assortative mating theory of autism. This theory requires further testing with large samples. This study also demonstrates that Asperger syndrome can be diagnosed by age 26 months. The aim of study 2 was to test if dyadic eye contact in infancy is intact in a child later diagnosed with Asperger syndrome. The same child's eye contact was measured at three time points (3, 6, and 9 months) over her first year of life and compared with that of age-matched controls. Although the child had low rates of eye contact at 6 months, it was within the normal range at all three points in the first year of life. We conclude that low levels of eye contact are not predictive of later development of Asperger syndrome. (J Child Neurol 2006;2l:35l-356; DOI 10.2310/7010.2006.00072). Autism spectrum conditions affect 1 in 200 children.''^ The causes are neurobiologic, including differences in brain function and structure,'^'' arising for genetic reasons.^'' The key symptoms are difficulty in social relationships and communication and an obsessional, detailed style of information processing.*'^ The earliest Received May 5, 2005. Received revised Sept 2, 2005. Accepted for publication Sept 25, 2005. From the Autism Research Centre (Profs Baron-Cohen and Scott, Ms Wheelwright, and Drs Bisarya, and Desai), Department of Psychiatry, University of Cambridge, Cambridge, UK; Neurocognitive Development Unit (Dr Johnson), Birbeck Coiiege, University of London, London, UK; and the Neonatology Department (Dr Ahluwaiia), Rosie Hospital, Cambridge, UK. Supported by the Medical Research Council. Address correspondence to Prof Simon Baron-Cohen, Autism Research Centre, Department of Psychiatry, University of Cambridge, Douglas House, 18b Trumpington Road, Cambridge CB2 2AH, UK. Tei: 01223 746057; fax: 01223 746033; e-mail:[email protected]{. point that detection of classic autism has been possible is age 18 months.'" Asperger syndrome is a subgroup on the autistic spectrum with a nonnal IQ and normal language development. It is typically detected later and rarely before 6 years of age." In this study, we tested if Asperger syndrome can be detected at a much younger age (26 months) than has hitherto been reported (study 1) and if eye contact in the first year of life is impaired in Asperger syndrome (study 2). We employed a single-case, family genetic design for three reasons. First, to demonstrate that Asperger syndrome can be identified early requires only a single case. One positive demonstration is sufficient to prove that it can be done, even if issues of reliability of diagnosis at this age would require larger samples to be studied. Second, the hypothesis that eye contact in the first year is impaired in Asperger syndrome can be disproved by demonstrating in a single case that eye contact is intact. Finally, testing both the principle of early detection and the development of eye contact in a child later diagnosed with Asperger syndrome is facilitated by studying a child at high risk of developing Asperger syndrome. In the two studies reported here, we took advantage of the