Isaac N. Pessah, Ph.D., Irva Hertz-Picciotto, Ph.D.
University of California, Davis
NIEHS Grants P01ES011269, R01ES015359
New results from the NIEHS-funded Childhood Autism Risks from Genetics and Environment (CHARGE) study show that children with autism had significantly more DNA deletions or duplications, known as copy number variants (CNV), than those with typical development. The researchers propose that a greater number of CNVs, especially those caused by duplication, could predispose people to autism.
The researchers examined data from 516 children with autism or typical development from the CHARGE study. The frequency of CNVs was significantly higher in the children with autism than for children with normal development. This remained true even after removal of rare and likely pathogenic events, showing that the CNVs consisted of more common variants not exclusively found in children with autism. The level of personal and social skills negatively correlated (Spearman's r = -0.13, p = 0.034) with duplication CNV load for the affected children. Communication (P = 0.048) and socialization (P = 0.022) scores showed the strongest associations.
The researchers say that finding an overall increase in genetic change in children with autism heightens the need to understand the basis of this variation. Although scientists know that environmental factors can affect the stability of the genome, the researchers note that it is not known if the increased CNVs found in the children with autism result from environmental exposures, nutrition, medical factors, lifestyle, genetic susceptibility, or combinations of many elements together.
Citation: Girirajan S, Johnson RL, Tassone F, Balciuniene J, Katiyar N, Fox K, Baker C, Srikanth A, Yeoh KH, Khoo SJ, Nauth TB, Hansen R, Ritchie M, Hertz-Picciotto I, Eichler EE, Pessah IN, Selleck SB. 2013. Global increases in both common and rare copy number load associated with autism. Hum Mol Genet; doi:10.1093/hmg/ddt136 [Online 27 March 2013].