Association of mtDNA Mutation with Autism in Iranian patients

The autism spectrum disorders (ASD) are amongst the most heritable complex disorders. Although there have been many efforts to locate the genes associated with ASD risk, many has been remained to be disclosed about the genetics of ASD. Scrutiny's have only disclosed a small number of de novo and inherited variants significantly associated with susceptibility to ASD. These only comprise a small number of total genetic risk factors. Some studies confirm the contribution of mitochondrial genome mutations to the pathophysiology of the autism, but some other studies rejected such a contribution. In the current study we tried to scrutinize the association between mitochondrial tRNA genes mutations and the risk of Autism. DNA was extracted from the blood of 24 patients with ASD and 40 age-matched healthy controls from Special Medical Center in Tehran. 22 tRNA genes of mitochondrial genome were PCR amplified using 12 primer pairs and sequenced. Sequencing results were searched for mutations using clustalW Progran and then the association of mutations with the autism risk was assessed by statistical analysis using SPSS version 15. Many of the observed mutations were sporadic mutations without any significant relationship with the risk of autism, and the other mutations including those of high frequency showed no significant relationship with the risk of disease as well (P>0.05) except mutations 16126T>C (P=0.01), 14569G>A(P=0.02) and 1811A>G(P=0.04). These three mutations were in the noncoding regions of the mitochondrial genome near tRNA genes. The mutation 16126T>C was in the mtDNA control region. Our study showed a significant relationship between the point mutations 16126T>C, 14569G>A and 1811A>G of the mitochondrial genome and the risk of autism.