Polymorphic Variants of Selected Genes Regulating Bile Acid Homeostasis in Women with Intrahepatic Cholestasis of Pregnancy

Intrahepatic cholestasis of pregnancy (ICP) is characterized by the onset of pruritus and elevated serum transaminases and bile acids (BA). The key enzyme in BA synthesis is CYP7A1, and its functions are regulated by various nuclear receptors. The goal of this study is to evaluate the association between CYP7A1, NR1H1, RXRA, and PPARA gene variants and risk of ICP. Five single nucleotide variants (SNVs), rs3808607 (CYP7A1), rs56163822 (NR1H4), rs1800206 (PPARA), rs749759, and rs11381416 (NR2B1), were genotyped in a group of 96 ICP and 211 controls. The T allele of the CYP7A1 (rs3808607) variant may be a protective factor against ICP risk (OR = 0.697, 95% CI: 0.495–0.981, p = 0.038). Genetic model analysis showed that rs3808607 was associated with decreased risk of ICP under dominant (OR = 0.55, 95% CI: 0.32–3.16, p = 0.032, AIC = 380.9) and log-additive models (OR = 0.71, 95% CI: 0.51–1.00, p = 0.046, AIC = 381.4). The A insertion in the rs11381416 NR2B1 variant was associated with the degree of elevation in the liver function tests TBA (34.3 vs. 18.8 μmol/L, p = 0.002), ALT (397.0 vs. 213.0 IU/L, p = 0.017), and AST (186.0 vs. 114.4 IU/L, p = 0.032) in ICP women. Results indicate an association between the CYP7A1 rs3808607 and the risk of ICP and the association of the rs11381416 of the NR2B1 receptor with higher values of liver function tests in women with ICP. A better understanding of the cooperation of proteins involved in BA metabolism may have important therapeutic implications in ICP and other hepatobiliary diseases.