A Unified Theory of Autism Revisited: Linkage Evidence Points to Chromosome X using a High-Risk Subset of AGRE Families

Kristina Allen-Brady, Dale Cannon, Reid Robison, William M. McMahon, and Hilary Coon


Finding autism susceptibility genes has been very challenging in part because multiple genes are likely to be involved in causing the disorder. New strategies are needed to successfully find autism genes. Zhao et al. (Proc Natl Acad Sci 2007;104:12831–12836) in their “Unified Theory of Autism” hypothesized how both sporadic male autism cases and male autism cases from high-risk families could exist. Using Autism Resource Exchange (AGRE) data, they theorized that the majority of male autism cases are from families with low autism risk and are due to new mutations. They further theorized that a subset of high-risk autism families inherits autism in a dominant manner, and identified 86 high-risk families likely to meet this criterion. As genotype data is now available for most of the AGRE dataset, the purpose of this manuscript was to test for evidence of dominant inheritance in the subset of 86 high-risk families identified by Zhao et al. We performed a genome-wide linkage analysis on the set of 86 high-risk families and identified a region on chromosome X that may explain autism in 11 of these high-risk families. The chromosome X region encompasses a large gene, IL1RAPL1, which has previously been shown to be involved in autism in three families. Finding new ways to locate autism susceptibility genes, such as using family structure as was done here, may help to identify and further our understanding of genes that cause autism. © 2010 INSAR/Wiley Periodicals, Inc

Article citation:Autism Res2010, 3: 47–52. DOI: 10.1002/aur.119

Reward Processing in Autism

Ashley A. Scott-Van Zeeland, Mirella Dapretto, Dara G. Ghahremani, Russell A. Poldrack, and Susan Bookheimer


One prominent feature of autism is decreased motivation to engage in social interactions. Reduced social motivation is apparent in children with autism as young as 12 months old, though the reason for this difference is not known. One theory suggests that children with autism do not pay attention to the social world because they do not find it rewarding. We investigated whether children with autism showed a typical brain activation pattern in response to rewards, particularly rewards that can guide learning. We used functional magnetic resonance imaging (MRI) to examine the brain's response to both social and monetary rewards in 16 high-functioning boys with autism spectrum disorders (ASD) and 16 age- and IQ- matched typically developing (TD) boys while they played two different learning games. One game provided monetary rewards for correct answers; the other provided social rewards (e.g., a smiling face). We found that, in TD boys, the reward processing centers responded to both monetary and social reward modulation. The ASD children, however, showed a reduced reward response for both monetary and social rewards, but were significantly different than TD children only for social rewards. Furthermore, we found that the amount of reward center response to learning-related social rewards correlates with a measure of social functioning in TD children. Together these data provide evidence for a reward processing deficit in autism. © 2010 INSAR/Wiley Periodicals, Inc

Article citation:Autism Res2010, 3: 53–67. DOI: 10.1002/aur.122

Motor-Linked Implicit Learning in Persons with Autism Spectrum Disorders

Brittany G. Travers, Mark R. Klinger, Joanna L. Mussey, and Laura G. Klinger


Individuals with autism spectrum disorders (ASD) tend to be deliberate and rule–based in their interactions with the world, which might be due to less reliance on implicit learning (i.e., learning that occurs without conscious awareness). The present study examined whether high-functioning adolescents and adults with ASD were able to implicitly learn keystroke motor movements and form “muscle memories” of these movements without conscious awareness. The results of the present study suggested that the individuals with ASD were able to learn the motor sequence as well as and at the same rate as individuals with typical development. The results of the present study, coupled with past findings, suggest that people with ASD may be able to learn motor movements without conscious awareness, especially if the individual is older and is learning fine motor sequences. © 2010 INSAR/Wiley Periodicals, Inc

Article citation:Autism Res2010, 3: 68–77. DOI: 10.1002/aur.123

Sensory Features and Repetitive Behaviors in Children with Autism and Developmental Delays

Brian A. Boyd, Grace T. Baranek, John Sideris, Michele D. Poe, Linda R. Watson, Elena Patten, and Heather Miller


Although atypical sensory features in children with autism are often reported, we still know little about their relationship to the established “core” features of autism. Much of the confusion centers on the third diagnostic category, restricted and repetitive behaviors and interests. This study examines how sensory features relate to repetitive behaviors both in children with autism and in children with developmental delays. We find that certain sensory features, specifically hyperresponsiveness (i.e., over-reactivity to sensory stimuli), are associated with repetitive behaviors in both groups of children. In comparison, hyporesponsiveness to sensory stimuli (i.e., under-reactivity to sensory stimuli) and sensory seeking behaviors (i.e., craving/fascination with sensory stimuli) have minimal, if any, relationship to repetitive behavior. The diagnosis and development of any intervention plan should be guided by a thorough understanding of the symptoms of each individual child, and the relationships between these symptoms. This study suggests that when children display hyperresponsive sensory features, they are also more likely to display repetitive behaviors. Behavioral or educational interventions may need to address the co-occurrence of these behaviors to maximize intervention effectiveness. © 2010 INSAR/Wiley Periodicals, Inc

Article citation:Autism Res2010, 3: 78–87. DOI: 10.1002/aur.124

Gender Discrimination of Eyes and Mouths by Individuals with Autism

Catherine A. Best, Nancy J. Minshew, and Mark S. Strauss


It has been suggested that many individuals with autism limit eye contact with other people. In general, few scientists have examined how attention paid to certain facial features relates to face processing abilities. Therefore, the current study tested individuals with autism in a simple gender discrimination task in which eyes and mouths were viewed in isolation from the whole face. By comparing the accuracy rates of individuals with autism with those of typically developing individuals, the authors concluded that participants with and without autism all discriminated gender more accurately from eyes alone than from mouths alone. However, adults with autism were significantly worse than typically developing individuals at discriminating gender from eyes. © 2010 INSAR/Wiley Periodicals, Inc

Article citation:Autism Res2010, 3: 88–93. DOI: 10.1002/aur.125