Investigating Serum miRNA Levels in Autistic Children with and without Bipolar Disorder: A Case-Control Study.

INTRODUCTION: The presence of bipolar disorder (BD) in individuals with ASD exacerbates social and cognitive impairments, complicates diagnosis and treatment. The aim of this study was to compare the serum levels of specific miRNAs between children with ASD with and without BD, and to explore their association with BD comorbidity in ASD. METHOD: A group of 41 pediatric patients with comorbid ASD + BD and a group of 47 pediatric patients with ASD without BD were included in the study. Serum miRNA levels were measured using quantitative real-time polymerase chain reactions, focusing specifically on miRNAs such as miR-132-5p, miR-134-5p, miR-206, and miR-126-5p. RESULTS: The ASD + BD group exhibited significantly greater ASD severity than the ASD without BD group. Serum levels of miR-134-5p, miR-206, and miR-126-5p were all higher in the ASD + BD group than in the ASD without BD group (p=0.038, p=0.023, and p=0.026, respectively), while miR-132-5p levels were not significantly different (p=0.105). Furthermore, miR-134-5p levels were correlated with the frequency of manic episodes in the ASD + BD group (p=0.007). CONCLUSION: The study findings suggest that miRNAs may be involved in the pathophysiology of comorbid BD in children with ASD and may potentially represent candidate biomarkers for early diagnosis and intervention, thus contributing to improved clinical outcomes in this population. Further research is now needed to validate these findings and to understand the underlying mechanisms.