Elevated mitochondrial DNA copy number in peripheral blood cells is associated with childhood autism

BACKGROUND: Several lines of evidence indicate mitochondrial impairment in the pathophysiology of autism. As one of the most common biomarkers for mitochondrial dysfunction, mitochondrial DNA (mtDNA) copy number has also been linked to autism, but the relationship between mtDNA copy number and autism was still obscured. In this study, we performed a case–control study to investigate whether mtDNA copy number in peripheral blood cells is related to patients with autism. METHODS: Relative mtDNA copy number in peripheral blood cells was measured by using real-time polymerase chain reaction method. The participants in this study included 78 patients with childhood autism and 83 typically developing children. RESULTS: We observed children with autism had significantly elevated relative mtDNA copy number than healthy controls (Beta = −0.173, P = 0.0003). However, there were no significant correlations between mtDNA copy number and clinical features (paternal age, maternal age, age of onset, illness of duration, CARS score and ABC score) in childhood autism. CONCLUSION: We show that elevated mtDNA copy number in peripheral blood is associated with autism, indicating that there may be mitochondrial dysfunction in children with autism.