MEF2C promoter variants in patent ductus arteriosus: a genetic and functional study.

Patent ductus arteriosus (PDA) is a common congenital heart disease (CHD) with a complex genetic basis. The transcription factor MEF2C plays a critical role in cardiac development, but the role of promoter region variants in PDA has not been explored. This study aimed to identify MEF2C promoter variants in PDA patients and investigate their functional consequences. We sequenced the MEF2C promoter region in 318 children with PDA and 306 healthy controls. Identified variants were subjected to dual-luciferase reporter assays in A7r5 vascular smooth muscle cells to assess transcriptional activity. Bioinformatics (JASPAR) and electrophoretic mobility shift assays (EMSA) were used to predict and validate changes in transcription factor binding. Seventeen variants were identified, of which seven were present exclusively in PDA patients. Three variants were novel. Dual-luciferase assays showed that six variants significantly altered promoter activity compared to wild-type (range 69.6%-82.3%). JASPAR prediction revealed that these variants affected binding sites for 16 transcription factors, including GATA1, GATA2, GATA3, STAT3, ZEB1 and E2F1. EMSA confirmed altered DNA-protein binding patterns for all six variants, and super-shift assays further validated that the g.24571 A > G variant specifically disrupts GATA3 binding. This is the first study to identify functionally relevant MEF2C promoter variants in PDA. Our findings suggest that dysregulation of MEF2C through promoter variants may contribute to PDA pathogenesis by disrupting critical transcription factor interactions. These results extend the genetic landscape of PDA beyond coding regions and provide new insights into the molecular mechanisms of CHD.