June 22, 2012

Study Explains Links between Autism and Genes

(Ivanhoe Newswire) -- Approximately three out of every 1,000 people in the United States suffer from some degree of Autism. Now, a new study is looking at why this happens by studying your genes.

Researchers at UCLA are conducting a study to explain why one person has an ASD (autism spectrum disorder) and another does not. The study pinpoints ASD risk factors by comparing changes in gene expression with DNA mutation data in the same individuals.

ASDs are a heterogeneous group of developmental conditions characterized by social deficits, difficulty communicating, and repetitive behaviors. ASDs are thought to be highly heritable, meaning that they run in families.

Researchers have found minimal changes in the number of copies in the genetic regions that associate with ASD. Although there are some hot-spot regions containing these alterations, very few genetic changes are exactly alike. Similarly, no two autistic people share the exact same symptoms.

In the study, 244 families were studied in which one child (the proband) was affected with an ASD and one was not. During this study several potential new regions where copy-number variants (CNVs) are associated with ASDs were identified. In addition, the team found genes within these regions that are significantly misregulated in ASD children compared with their unaffected siblings.

"Strikingly, we observed a higher incidence of haploinsufficient genes in the rare CNVs in probands than in those of siblings, strongly indicating a functional impact of these CNVs on expression," Dr. Daniel Geschwind of UCLA was quoted saying.

Haploinsuffiency occurs when only one copy of a gene is functional; the result is that the body cannot produce a normal amount of protein. The researchers also found a significant enrichment of misexpressed genes in neural-related pathways in ASD children

Source: Cell Press, June 2012