No Association Between Autism Spectrum Disorder and Mitochondrial DNA Variants: A Comprehensive Genetic Study in...

Area of Science:

• Genetics
• Neurodevelopmental Disorders
• Mitochondrial Biology

Background:

• Autism spectrum disorder (ASD) has a strong genetic component, but etiological factors are often unknown.
• Mitochondrial DNA (mtDNA) variations are hypothesized contributors to ASD, yet evidence remains inconclusive due to study limitations.

Purpose of the Study:

• To investigate the association between mtDNA variants, gene-level variant burden, and haplogroup distributions in Turkish children with ASD.
• To comprehensively analyze the role of mtDNA in the pathogenesis of ASD.

Main Methods:

• Whole mtDNA sequencing of peripheral blood from 95 children with ASD and 95 controls.
• Pathogenicity evaluation using genomic databases and in silico analyses.
• Segregation analysis and mtDNA haplogroup comparison.

Main Results:

• Higher overall mtDNA variant frequency in the ASD group, with variants initially classified as pathogenic/likely pathogenic (P/LP) or variants of uncertain significance (VUS).
• Increased variant load in the MT-CYB gene in the ASD cohort.
• Segregation analysis revealed maternal inheritance of P/LP variants from asymptomatic mothers, leading to reclassification as VUS. No significant difference in haplogroup distribution.

Conclusions:

• mtDNA variations do not appear to be implicated in ASD pathogenesis based on this study.
• Larger sample sizes, standardized pathogenicity criteria, and detailed phenotypic analysis are required for future research on mtDNA and ASD.