PREVALENCE OF COMMON MITOCHONDRIAL POINT MUTATIONS IN AUTISM

Objectives: Autistic features have been reported in patients with mitochondrial disorders with diverse molecular defects. The objective of this study is to estimate the prevalence of common mitochondrial point mutations in autistic disorders.

Methods: We screened 810 cases with Autism, Asperger syndrome and Pervasive Developmental Disorder from Autism Genetics Resource Exchange for mitochondrial A3243G, T8993G, T8993C and A8344G mutations. Given the maternal transmission of mitochondrial DNA, samples from 378 mothers of the affected children were also investigated. Mitochondrial DNA analyses were performed in all subjects by restriction fragment length polymorphism (RFLP) assays.

Results: A3243G mutation was detected in DNA samples from two male cases with autism from one pedigree in this family collection. These two patients manifested isolated autistic spectrum features. Their asymptomatic mother also had A3243G mutation in blood.

Conclusions: The prevalence of A3243G mutation in the AGRE population is 2/810 or 0.25% (95% confidence interval 0.08% to 0.9%). Considering the low sensitivity of the RFLP assays for detection of heteroplasmic mutation in blood, our results provide a minimum point estimate of A3243G mutation in autism and the true prevalence of A3243G mutation in autism could be higher.