Minor alleles of genetic variants in second heart field increase the risk of hypoplastic right heart syndrome

ABSTRACT

Hypoplastic right heart syndrome(HRHS) is characterized by hypoplastic right ventricle (RV); Numerous transcriptional cascades in the second heart field (SHF) regulateRVdevelopment. The relationship of SHF gene variants with humanHRHS remains unknown. The whole lengths of 17 SHF genes were sequenced in 16 HRHS, and the selected single-nucleotide variants (SNVs) were then genotyped in HRHS, other congenital heart disease (CHD) and healthy control. Luciferase assay was performed to verify the effect of FOXC2 rs34221221A>GandTBX20 rs59854940C>Gat the transcription level. There were 151 (12.86%) novel SNVs after sequence analysis, of which three were in exons (one was synonymous SNV and two were nonsynonymous SNVs), two in promoter, and most SNVs (89.95%) were in intronic regions. Genotype analyses revealed that the minor alleles of FOXC2 rs34221221 A>G and TBX20 rs59854940 C>G could increase HRHS risk (P<0.05), but not in other CHD or healthy control. Luciferase assay showed that the minor G allele in rs34221221 significantly increased FOXC2 transcription while in rs59854940 it decreased TBX20 transcription significantly. Novel variants of SHF gene associated with HRHS were identified. Minor alleles in two variants from FOXC2 and TBX20 could increase the risk of HRHS.