Irva Hertz-Picciotto, Ph.D.
University of California, Davis
P01ES011269, R01ES015359, R01ES020392
New findings from the NIEHS-funded Childhood Autism Risk from Genes and Environment (CHARGE) study show that children with autism as well as their fathers have altered p53 gene copy ratios and increased mitochondrial (mt) DNA deletions, which are markers of molecular stress and damage in the cell’s nucleus and mitochondria. The research results suggest that DNA repair capacity and genome instability might have a role in autism.
The study included 66 children with autism and their parents as well as 46 age-matched typically developing children and their parents, all of whom participate in the CHARGE study. The investigators examined the mtDNA copy number and deletions and p53 gene copy ratios in lymphocytes from children and both parents. In the presence of an environmental stressor, p53 stops cell division to allow repair of damaged DNA.
Higher p53 gene copy ratios and mtDNA deletions were more that twice as common in children with autism. Fathers of children with autism showed double the incidence of mtDNA deletions of age-matched fathers of typically developing children, suggesting a role for deficient DNA repair capacity not necessarily tied to paternal age.
The researchers say that the mtDNA deletions and altered p53 gene copy ratios seem to result from genetics in children with more severe autism while gene-environment interactions seem to play a greater role in children with autism with less severe symptoms.
Citation: Wong S, Napoli E, Krakowiak P, Tassone F, Hertz-Picciotto I, Giulivi C. 2016. Role of p53, mitochondrial DNA deletions, and paternal age in autism: a case-control study. Pediatrics 137(4):e20151888.