miR-146A and miR-146B Promoter Methylation and Common Sequence Variations Are Not Likely to Be Involved in Autism Spectrum Disorder.

Researchers studied whether changes in two specific genes (miR-146A and miR-146B) might cause autism. They compared DNA samples from 93 children with autism to 44 children without autism. They found no major differences in how these genes were modified or varied between the two groups. One child with autism had a unique gene change, but overall, these particular genes don't appear to be important causes of autism.

This Egyptian case-control study examined whether epigenetic modifications (promoter methylation) and genetic variations in microRNAs miR-146A and miR-146B contribute to autism spectrum disorder. Researchers analyzed DNA from 93 autistic children (ages 5-16) and 44 controls using methylation-specific PCR and Sanger sequencing. No significant differences in promoter methylation levels or common genetic variants were found between ASD cases and controls. However, one novel upstream variant in miR-146A was identified in a single autism case.

The findings suggest that methylation and common genetic variations in these specific microRNAs are unlikely to play significant roles in ASD pathogenesis in this population.

These findings suggest miR-146A and miR-146B methylation patterns and common variants are not useful biomarkers for ASD diagnosis or risk assessment. The novel variant discovery indicates regulatory regions warrant further investigation in larger studies.

Single population study (Egyptian), relatively small sample size, cross-sectional design, and novel variant found in only one case. Functional validation of the discovered variant was not performed.

One of the well-studied epigenetic regulators is miRNA (miRNA) which plays critical roles in gene regulation and has been implicated in autism spectrum disorder (ASD) pathology, particularly through their involvement in neuroinflammation and neuronal regulation. MiR-146A and miR-146B are of special interest due to their dysregulation in ASD. Epigenetic modifications, such as promoter methylation, and genetic variations in miRNAs can influence their expression and function, yet their roles in ASD remain unclear. This study aimed to investigate promoter methylation patterns and sequence variations in miR-146A and miR-146B to evaluate their potential contributions to ASD.

The study included Egyptian patients with ASD (ages 5-16 years) diagnosed using DSM-V criteria and assessed for severity using the Childhood Autism Rating Scale (CARS). DNA was extracted from peripheral blood samples of 93 autistic patients and 44 age-matched controls. Methylation-specific PCR (MSP) was used to analyze promoter methylation of miR-146A and miR-146B, while Sanger sequencing was employed to detect sequence variations in these genes and their flanking regions. Statistical analyses included independent t-tests, ANOVA, ROC curve, and Pearson correlation.

No significant differences in promoter methylation levels of miR-146A and miR-146B were observed between ASD cases and controls or among severity subgroups (P > 0.05). Sequence variation analysis identified no significant differences in the distribution of common SNPs (rs2910164 and rs2224374). However, a novel miR-146A upstream variant (C/A at 5:160,485,254) was discovered in one case with autism. Methylation and common genetic variations in miR-146A and miR-146B are unlikely to play significant roles in ASD in this population.

The discovery of a novel upstream variant highlights the potential importance of regulatory regions in miRNA function. Further studies with larger cohorts and functional validation are recommended.