As part of their 2003-2004 Distinguished Lecturer Series, the University of California at Davis M.I.N.D. Institute recently hosted researcher Susan E. Folstein, M.D. who discussed her latest discoveries in genetic research into autism. Dr Folstein's research team, The Collaborative Autism Project (CAP), along with Cure Autism Now's Autism Genetic Resource Exchange and other leading genetic research teams, are part of a large collaboration to initiate and uncover answers to the link between genetics and the neurobiology of autism spectrum disorders.
In her presentation held Wednesday, Feb. 11, Folstein noted that autism is the most strongly inherited neurodevelopmental disorder. She said a small minority of cases are caused by one gene, such as the one for Fragile X; however, in most cases, several genes must combine together to cause the condition. In addition, different families may have different combinations of genes. Folstein's research supports the theory of many researchers working in this field ? that autism is a complex disease and may not have the same combination of causes in every individual.
Clinical Subgroups Help Define Genetics
Dr. Folstein and her team examined the hypothesis that if several genes are involved in causing autism, at least some of those genes should have a detectable physical trait (phenotype). At the M.I.N.D. Institute presentation, Folstein described her work, which utilizes the variability in the clinical features in individuals with autism to increase the statistical power to detect autism-related genes. By analyzing subsets of families, based on a particular clinical trait of the autism, several chromosomal regions have yielded improved evidence that a gene influential in autism may be present. In other words, rather than lumping all children with autism together for the purpose of analysis, separating them into clinically meaningful subgroups is leading to validation of several genetic links.
"When you have a significant signal in a particular region, it gives you lots of clues as to where to start looking", said Folstein, adding that once chromosomal markers are identified, the next phase is to examine the possible interactions between the genes in a particular region.
Continuing to test additional markers will narrow the search area of the genes, Folstein said. Markers that are very close to a gene are said to be "linked" to that gene because the marker and the gene are almost always inherited together. Once scientists find a set of markers that are linked to a gene, then they say that they have found linkage. It is important to remember that linkage does not mean that a gene has been identified, but rather that the gene being searched for is somewhere nearby.
Folstein, a professor of psychiatry and genetics at Tufts University School of Medicine, is trained in pediatrics and completed residencies in psychiatry and child psychiatry. After a fellowship in medical genetics at Johns Hopkins, she joined the faculty there and started the department's program in psychiatric genetics. Her focus has been on the interface between psychiatry and genetics, with most of her work focused on autism and Huntington's disease.
If your family or a family you know of has more than one child diagnosed with autism, PDD, or Asperger's syndrome, please contact AGRE through our contact page.