Promoter methylation and expression of the VANGL2 gene in the myocardium of pediatric patients with tetralogy of fallot.

BACKGROUND

Tetralogy of Fallot (ToF) is the most common form of cyanotic congenital heart disease and is a major cause of significant morbidity and mortality. VANGL2 is a critical gene in the planar cell polarity pathway that plays an important role in the development of the heart. This study investigates the methylation status of the promoter region of VANGL2 and the expression pattern of VANGL2 in cardiac tissue.

METHODS

The promoter region of VANGL2 was sequenced in 200 ToF patients and 400 control subjects. Methylation levels were measured in four regions of the VANGL2 promoter (B1-1: -282 bp ∼ -117 bp, B1-2: -117 bp ∼ 41 bp, B2: 8 bp ∼ 157 bp, B3: 132 bp ∼ 401 bp) by bisulfite sequencing PCR in the right ventricular outflow tract of the myocardium. Quantitative real-time PCR and immunohistochemistry were used to detect the mRNA and protein expression levels, respectively.

RESULTS

No mutations were found in the promoter region, but two SNPs (rs11582932 T>G, rs11265385 T>G) were found in ToF patients and controls with similar frequencies (p>0.05). The overall methylation status of the VANGL2 promoter was significantly higher in ToF patients than in controls (p=0.0234). Specifically, the methylation levels of regions B1-1 and B3 were significantly higher in ToF patients (p=0.0042, p=0.0418). Both the VANGL2 mRNA and protein levels were significantly lower in ToF patients than in controls (p<0.05).

CONCLUSION

The aberrant VANGL2 promoter methylation and the decreased gene expression in ToF patients may provide important clues for the development of ToF.