Abstract： Objective To investigate the role and mechanism of miR-103a-3p in the development of Hirschs-prung disease(HSCR).Methods The expression levels of miR-103a-3p in the constricted and dilated segments of colon tissue from HSCR patients were analyzed using RT-PCR.The effects of miR-103a-3p on cell proliferation and migration were assessed using CCK-8 and Transwell assays.Potential target genes were predicted using KEGG,GO,and protein-protein interaction network analyses.The target gene PIK3R1 of miR-103a-3p was validated at both cellular and tissue levels using RT-PCR,Western blot,and dual-luciferase reporter assays.Results miR-103a-3p was sig-nificantly upregulated in the constricted segments of colon tissues from HSCR patients.miR-103a-3p inhibited cell pro-liferation and migration.Bioinformatics analysis suggested that PIK3R1 is a potential target gene of miR-103a-3p in HSCR.Dual-luciferase reporter assays confirmed that miR-103a-3p binds to the 3'-UTR of PIK3R1 and affects its mRNA and protein expression levels.In tissue samples,PIK3R1 expression was significantly reduced in the constricted segments,showing a negative correlation with miR-103a-3p expression.Conclusion miR-103a-3p is differentially expressed in the pathological intestinal segments of HSCR and plays a crucial role in the disease by targeting PIK3 RI,in-fluencing cell proliferation and migration.