G9055a Substitution in MTDNA: an Important Variant in Autism
Autism spectrum disorders [ASDs] are neuro developmental complex diseases with causative de-novo and
inherited genetic factors. They contain a range of cognitive and behavioral conditions such as Asperger's syndrome, pervasive
developmental disorder and autism. Our study cases were children with autistic behaviors [15-60 CARS Score]. The DNA
extraction process was done by GeNet Bio DNA extraction kit, and the region of interest was amplified using independent
PCR runs. After purification of PCR products, both strands were sequenced by a Big Dye Termination system. The automated
sequencing on an ABI 3700 was directly determined with a capillary sequencer machine. Both primers sequencing results
were analysed using bioinformatics' tool, Sequencher Software 5. In this study, 31 samples were examined which 14 unique
variants were detected in genes related to ATPase6/8 and tRNA. One of the variants known as G9055A [CAAD>20 and
PolyPhen is shown to be Probably damaging] seems pathogenic according to PolyPhen and CADD scores. In the variant
G9055A of ATP6, amino acid alanine converts to threonine. A to T substitutions induce accumulation of amiloid fibril in the
brain because threonine prefers to form βsheet as a necessary stage in the amyloidogenic process. In our study of patients with
autism, we found one case having an interesting association with amyloidosis. It is hoped that by finding such markers, the
children will be treated with more certainty.
Index Terms - Amyloidogenic process, Autism spectrum disorders, mtDNA variation.