Mild decrease in TBX20 promoter activity is a potentially protective factor against congenital heart defects in the...

Area of Science:

• Genetics
• Developmental Biology
• Cardiovascular Research

Background:

• Congenital heart defects (CHDs) are common birth defects globally.
• TBX20 is essential for embryonic cardiovascular development, with coding region mutations linked to CHDs.
• The role of TBX20 regulatory region variants in CHDs is largely unexplored.

Purpose of the Study:

• To investigate the association between variants in the TBX20 regulatory region and CHD occurrence.
• To explore the functional impact of identified TBX20 regulatory variants.

Main Methods:

• Sequencing of the 2kb upstream region of TBX20 in 228 CHD patients and 292 controls.
• Identification and linkage disequilibrium analysis of single nucleotide polymorphisms (SNPs).
• Functional assays including transcriptional activity assessment and electrophoretic mobility shift assay (EMSA).

Main Results:

• Six identified SNPs were in strong linkage disequilibrium, with minor alleles associated with reduced CHD risk (rs10235849: p=0.0069, OR=0.68).
• Minor alleles demonstrated lower transcriptional activity in human heart tissues and cell lines.
• EMSA indicated potential higher binding affinity of minor alleles with transcription repressors.

Conclusions:

• TBX20 regulatory variants, specifically minor alleles, are associated with a lower risk of congenital heart defects in the Han Chinese population.
• Moderately reduced TBX20 activity may be protective against CHDs, offering new insights into CHD etiology.