The Functional Polymorphism R129W in the Gene Is Associated with Sporadic Tetralogy of Fallot in the Han Chinese Population.

Tetralogy of Fallot (TOF) accounts for ∼10% of congenital heart disease cases. The blood vessel epicardial substance () gene has been reported to play a role in the function of adult hearts. However, whether allelic variants in contribute to the risk of TOF and its possible mechanism remains unknown. The open reading frame of the gene was sequenced using samples from 146 TOF patients and 100 unrelated healthy controls. qRT-PCR and western blot assays were used to confirm the expression of mutated variants in the TOF samples. The online software Polyphen2 and SIFT were used to predict the deleterious effects of the observed allelic variants. The effects of these allelic variants on the transcriptional activities of genes were examined using dual-fluorescence reporter assays. We genotyped four single nucleotide polymorphisms (SNPs) in the gene from each of the 146 TOF patients. Among them, the minor allelic frequencies of c.385C>T (p.R129W) were 0.035% in TOF, but ∼0.025% in 100 controls and the Chinese Millionome Database. This allelic variant was predicted to be a potentially harmful alteration by the Polyphen2 and SIFT softwares. qRT-PCR and western blot analyses indicated that the expression of in the six right ventricular outflow tract samples with the c.385C>T allelic variant was significantly downregulated. A dual-fluorescence reporter system showed that the c.385C>T allelic variant significantly decreased the transcriptional activity of the gene and also decreased transcription from the and promoters. c.385C>T (p.R129W) is a functional SNP of the gene that reduces the transcriptional activity of and in TOF tissues. This subsequently affects the transcriptional activities of and related to TOF. These findings suggest that c.385C>T may be associated with the risk of TOF in the Han Chinese population.