Human Genetics at IMFAR
Genetic research is one of the exciting avenues of investigation that was highlighted at this year’s IMFAR meeting. The section on human genetics started with a description of the largest study of autism twins to date. This study, described by Dr. Joachim Hallmayer, has concluded the data collection phase and is beginning to shed new light on how much autism can be explained by genes and how much by environment. Because identical twins share 100% of their DNA while fraternal twins share only approximately 50%, geneticists can compare the relative contribution of genes and environment, since it is assumed that for each twin pair, the environment is the same. Clearly, both environment and genes are involved but this study may help to identify to what extent.
Dr. David Ledbetter described his effort to gather anonymous genetic information on chromosomal microarays from hundreds of thousands of patients with autism spectrum disorder and developmental delay. He is doing this by forming partnerships with over 120 clinical labs throughout the U.S. Dr. Ledbetter, a world-reknown expert in cytogenetics, has the knowledge and respect of the scientific community to achieve the goal of creating data standards and pooling information to show which chromosomal changes are most often identified in these groups. Deletions in regions on chromosomes 16 and 22 are identified consistently. Although still rare, an understanding of altered genes in these regions may lead us to identify new subtypes of autism.
Other talks focused on studies of brain and face development (since these happen at the same time) in families with autism from the Autism Genetic Resource Exchange, an update from the Autism Genome Project, and a fascinating talk from Sun-Chiao Chang (working with Dr. Susan Santangelo) on sex-specific effects in autism spectrum disorder. Ms. Chang identified several genes which seem to have an effect only in males, possibly helping to explain the common finding that there are four times as many males with autism as there females.
To read complete coverage from IMFAR, please visit http://www.autismspeaks.org/science/science_news/imfar_2010.php.