Autism Linked to Gene Variants

Autism
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There are three recently published studies about autism, two published online in Nature and one in Annals of Human Genetics, which point strongly to autism being genetic in nature.

The researchers initially studied DNA from more than 3,100 individuals from families affected with autism-related disorders. The Dr Hakon Hakonarson and colleagues’ study reported in Nature involved more than 12,000 people. Included were people with autism, their relatives, and healthy individuals with no known family history of autism.

Variants in neuronal cell-adhesion molecules were found. One of the studies also found autism-related variants in genes associated with the ubiquitin-proteasome system that rids cells of unneeded proteins. The researchers speculate that even these variants might affect cell adhesion by altering turnover of proteins at the cell surface.

Dr. Hakonarson and colleagues feel that these variants may contribute to as many as 15% of the autism spectrum disorder cases.

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The study in Annals of Human Genetics was led by Margaret Pericak-Vance, Ph.D., of the Miami Institute for Human Genomics, who was also a co-investigator on one of the Nature studies. This study also found a cluster of variants in the 5p14.1 region of chromosome 5 associated with autism disorders.

All the researchers feel that these findings are important because they make functional sense. Adhesion molecules help cells stick together to form tissues. They are critical structural components which help build and maintain neural connections.

The studies were supported by the Margaret Q. Landenberger Foundation, the Cotswold Foundation, the Mental Retardation and Developmental Disability Research Center at CHOP, the Beatrice and Stanley A. Seaver Foundation, the Department of Veterans Affairs, the NIH, the Utah Autism Foundation, the Hussman Foundation, the Autism Genome Project Consortium, the Medical Research Council (UK) and the Health Research Board (Ireland).

Source references:
Common genetic variants on 5p14.1 associate with autism spectrum disorders; Nature 2009; DOI: 10.1038/nature07999; Wang K, et al

Autism genome-wide copy number variation reveals ubiquitin and neuronal genes; Nature 2009; DOI: 10.1038/nature07953, Glessner JT, et al

A Genome-wide Association Study of Autism Reveals a Common Novel Risk Locus at 5p14.1 (p 263-273); Annals of Human Genetics, Volume 73 Issue 3, Pages 274 – 282 Published Online April 20, 2009 (DOI: 10.1111/j.1469-1809.2009.00523.x); Deqiong Ma, Daria Salyakina, James M. Jaworski, Ioanna Konidari, Patrice L. Whitehead, Ashley N. Andersen, Joshua D. Hoffman, Susan H. Slifer, Dale J. Hedges, Holly N. Cukier, Anthony J. Griswold, Jacob L. McCauley, Gary W. Beecham, Harry H. Wright, Ruth K. Abramson, Eden R. Martin, John P. Hussman, John R. Gilbert, Michael L. Cuccaro, Jonathan L. Haines, Margaret A. Pericak-Vance

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