More than a thousand scientists, clinicians, and members of the public gathered today at the Royal Pedregal Hotel in Mexico City for Autism Speaks to the World, an International Congress for Autism Research, hosted by Autism Speaks and the Mexican Autism Clinic, A.C. (CLIMA). Ongoing from June 5-7, 2007, the Congress will promote awareness, treatment services, and autism research throughout Mexico and the world. For a live web cast of the conference, log onto http://www.autismcongress.org from 10:30 a.m. to 7:30 p.m. EDT on July 6 and 7.
First Lady Margarita Zavala, the wife of Mexican president Felipe Calderón, inaugurated the conference, saying the upcoming presentations would advance “not just awareness of autism, but also knowledge of mankind.” Dr. Carlos Marcin, founder of CLIMA and Emeritus Professor of the Ibero Americana University in Mexico City followed by noting that autism patients in Mexico were once seen as “kids living in a fantasy world, indifferent to the world around them.” But scientific understanding of the disorder has grown steadily, he added. Experts now recognize autism as a “triad of impairments,” that includes difficulty relating to other people and social situations, difficulty communicating effectively, and a tendency towards rigid or repetitive behaviors.
Speakers throughout the day described the latest findings on autism's global distribution, its physical and behavioral characteristics, and its causes. Eric Fombonne, a psychiatric epidemiologist who heads the division of child psychiatry at McGill University, cited numerous replicated studies suggesting that autism's global prevalence ranges from six to seven cases per thousand individuals. Those figures represent a sharp increase from earlier estimates, which as recently as the early 1990s averaged up to 2.5 cases per thousand. But Fombonne stopped short of claiming there is an epidemic of autism. Rather, he said, higher estimates now might reflect diagnostic changes, better case finding, and the effect of the 1990 Disabilities Education Act in the United States, which directed states to report autism cases specifically, instead of lumping them together with other neurodevelopment disorders.
Current prevalence figures raised a stark concern for Marcin, who pointed out that according to the latest inquiry; just 2751 cases of autism were being treated in Mexico. Applying a conservative prevalence estimate of 1/1000 to Mexico's population, he said, would suggest 7,000 cases should be treated in Mexico City alone. CLIMA now hopes to identify more cases, with a certificate course designed to instruct teachers, parents, and caregivers the basics of early autism detection and intervention procedures. “We think CLIMA could be a role model for other [developing countries],” he said.
Catherine Lord, who directs the University of Michigan Autism and Communication Disorders Center, claimed behavior patterns at the age of two predict disease characteristics at later stages. She manages a long-term study of 214 autistic children, currently 16-18 years of age, who were recruited at the age of two and then evaluated at three, five, and nine years of age. That research shows the vast majority of children diagnosed at two still have either autism or one of the autism spectrum disorders today. Most diagnostic changes—typically involving a shift from “pervasive developmental disorder-not otherwise specified (PDD-NOS)” to autism—occurred between the ages of two and five, indicating that uncertain assessments made during early childhood had strong predictive value. Other early features were also predictive, she added. For instance, children with strong repetitive symptoms were more likely to have behavioral problems later in life; those with lesser verbal skills were more prone to attention deficit disorder; while those with stronger verbal skills were more prone to depression.
Two views on the cause of autism followed. Margaret Pericak-Vance, director of the Miami Institute for Human Genomics, stressed that autism's underlying genetic features are more complex than previously anticipated. While scientists once thought one or a few genes might explain the genetic risk for autism, as they do for other diseases like Huntington's chorea, more recent evidence suggests that 20 to100 genes might be involved, each contributing a small fraction to the overall risk, she said. That disheartening finding was buoyed by technical advances that are now making it possible to screen for susceptibility genes more effectively, however. Whole genome association, for instance, a new technology that had led to recent advances in the genetics of diabetes and cardiovascular diseases, allows scientists to screen for up to one million gene variations at once, she said. Recent findings by researchers from the Cold Spring Harbor Laboratory and the Autism Genome Project, both Autism Speaks-supported, using that and other novel techniques offer an additional note of optimism.
Environmental chemicals might also exacerbate genetic risks for autism, said Isaac Pessah, director of the Center for Environmental Health and Disease Prevention at the University of California, at Davis. Up to 80,000 commercially important chemicals are on world markets today, he said. Most of them are untested for toxicological effects. Some of these—organophosphate and neo-nicotinoid insecticides, for instance—might affect the balance of excitory and inhibitory neurons in the brain, he said. Alternations in these particular neurons have already been implicated in autism, suggesting the chemicals might further exacerbate risks for the disease. Chemicals might also heighten disease risks by affecting pathways like those involving the brain's GABA receptors, Pessah added. Of particular concern was the possibility that chemicals might affect pathways that both GABA and exitory and inhibitory neurons share in common: namely, calcium signaling.
Finally, two speakers described new findings on the behavioral manifestations of autism. Helen Tager-Flusberg, a professor at Boston University, described her work on language and communication impairments in autistic children. Insights into how autism affects communication can be obtained from the “theory of the mind,” she said, which postulates that people communicate through mutual understanding of each other's mental states. Autistic children lose that capacity, which renders them unable to understand the nuances and ordinary inferences upon which normal communication depends, she said. Ami Klin, who directs the Autism Center at Yale University School of Medicine, concluded the day's presentations with a fascinating discussion of eye-tracking studies in autistic individuals of all ages. According to his research, autistic children from infancy onwards focus not on the eyes of others, but rather on their mouths, or on random movements in their visual range. To those with autism, the world is more a place of things than people, he said. Unable to relate to visual signals of personal relations, autistic people can't follow social interactions if they unfold too quickly, he explained. Ideally, it may one day be possible to manipulate vulnerabilities for autism at a young age, Klin said. “And that would be critically important for us—we don't know if we can reverse autism, but we may be able to alter the natural course of this condition.”