OBJECTIVE: The target of this research was to explore the serum miR-195-5p expression in children with autism spectrum disorder (ASD) and its association with the disease severity. METHODS: The research enrolled 30 ASD children as the study group and 30 typically developing children as the control group. MiR-195-5p and FGFR1 were detected in the serum and cells of subjects via real-time quantitative PCR (RT-qPCR). The diagnostic values of miR-195-5p and FGFR1 were assessed using receiver operating characteristic (ROC) curves. The Pearson correlation coefficient was employed to assess the relationship between miR-195-5p and childhood autism rating scale (CARS), autism behavior checklist (ABC), and Clancy autism behavior scale (CABS) scores, as well as the correlation between miR-195-5p and FGFR1. Bioinformatics was utilized to predict the miR-195-5p-targeted gene. The interaction between miR-195-5p and FGFR1 was validated through luciferase reporter assay. RESULTS: Serum miR-195-5p levels were significantly increased in ASD children (P <
0.002). The ROC results indicated that miR-195-5p had the ability to differentiate between ASD children and control groups. The Pearson correlation coefficient confirmed that miR-195-5p was positively correlated with the CARS score (r = 0.6699), ABC score (r = 0.5386), and CABS score (r = 0.7096). Luciferase reporter experiments and RT-qPCR demonstrated that FGFR1 served as a downstream target gene of miR-195-5p. Further studies revealed that FGFR1 levels were decreased in ASD children (P <
0.002) and FGFR1 exhibited a negative correlation with miR-195-5p. The ROC results signified that FGFR1 could also distinguish ASD children from the control group. CONCLUSION: Serum miR-195-5p was elevated in ASD children and was positively associated with the disease severity. MiR-195-5p might function as a diagnostic and treatment target for ASD.