Mice Study Shows Mutation in Mitochondrial DNA Exhibits Altered Brain Activity
A new study has demonstrated that defects in the mitochondria of brain cells may be the root cause of autism spectrum disorder (ASD). This compelling work was produced by researchers at Children’s Hospital of Philadelphia (CHOP) and published online in the Proceedings of the National Academy of Sciences. Over the years, numerous studies have reported that hundreds of genetic mutations are associated with the etiology of autism. However, there has been little agreement on how these changes cause the disorder. Recent analyses have suggested that deficiencies in mitochondria, the tiny energy producers contained inside of cells, could be a cause of ASD. Other studies have demonstrated that variants of mitochondrial DNA (mtDNA) are linked to autism. The researchers at CHOP speculated that if mitochondrial defects predispose individuals to ASD, then a mouse model using relevant mtDNA mutations should cause the mice to present with symptoms of autism. The research team’s hunch proved correct. When they introduced a mild missense mutation in the mtDNA ND6 gene into a mouse strain, the rodents exhibited impaired social interactions, increased repetitive behaviors and anxiety. These symptoms are consistent with autism. The researchers also discovered that the mice had irregularities in electroencephalograms (EEG), more seizures and brain-region defects on mitochondrial function. Interestingly, despite these observations, the mice exhibited no structural changes to their brain’s anatomy. This incredible observation points to mitochondrial defects alone being sufficient enough to cause autism. The CHOP research team acknowledge that this hypothesis needs more study, however they believe treating mitochondrial function could lead to better autism diagnostics and treatments in the future.
