Two functional sequence variants of the GATA6 gene promoter in patients with indirect inguinal hernia

Inguinal hernia is a common surgical disease, majority of which are indirect inguinal hernia (IIH). A positive family history has indicated that genetic factors play important roles in the IIH development. To date, genetic causes and underlying mechanisms for inguinal hernia remain largely unknown. During the embryonic development, GATA transcription factor 6 (GATA6) plays an essential role. Mutations in GATA6 gene and changed GATA6 levels have been associated with human diseases. As GATA6 acts in a dosage-dependent manner, we speculated that changed GATA6 levels, resulting from DNA sequence variants (DSVs) within the gene regulatory regions, may mediate the IIH development. In this study, the GATA6 gene promoter was genetically and functionally analyzed in IIH patients and ethnic-matched controls. Eleven DNA sequence variants (DSVs), including four SNPs and seven new variants, within the GATA6 gene promoter were identified. Two heterozygous DSVs, g.22168361C>A and g.22169106C>T, were identified in two IIH patients, but in none of controls. In cultured human fibroblast, these DSVs significantly reduced the GATA6 gene promoter activities. In addition, three heterozygous DSVs were only found in three controls. Five DSVs, including four SNPs and one new variant, were found in both IIH patients and controls with similar frequencies. Therefore, the DSVs within the GATA6 gene promoter may contribute to the IIH development as a risk factor by changing the GATA6 levels.