Pathophysiological Significance of Variants of the HAND1 Gene Promoter in Congenital Atrial Septal Defects: A Study in 632 Chinese Subjects.

BACKGROUND

Atrial septal defect (ASD) is a common congenital heart disease (CHD) and genetic variation in the HAND1 gene is associated with cardiac development. The variants in the promoter region of the HAND1 gene are unknown.

METHODS

We performed Sanger sequencing of DNA from 632 subjects (320 ASD patients and 312 healthy controls). The identified variants were also subjected to further cellular functional validation, electrophoretic mobility shift analysis (EMSA), and JASPAR database analysis.

RESULTS

A total of 12 variants were identified in the promoter region of HAND1 gene, seven of which were found only in 10 ASD patients (g.3658 T > C [rs1287904093], g.3689 A > G, g.3714 G > A [rs140545341], g.3771 C > T [rs2113306555], g.3961 T > G, g.4411 A > T [rs1034236730], and g.4512 G > T) and three of the variants (g.3689 A > G, g.3961 T > G, and g.4512 G > T) were newly discovered. Further cellular functional validation showed that these seven variants reduced the transcriptional activity of HAND1 gene promoter (p < 0.05). The results of EMSA and the analysis of the JASPAR database suggest that these variants may have altered a series of transcription factor binding sites (TFBs), leading to altered HAND1 protein expression as well as the development of ASD.

CONCLUSIONS

Thus, the present study provides new insights into the role of the promoter region of HAND1 gene, which could lead to a better understanding of the genetic basis of ASD formation and potential treatments.