Aim: To evaluate the role of genetic factors in the pathogenesis of idiopathic infant cholestasis.
Methods: We performed a case-control study, including 78 infants with idiopathic infant cholestasis and 113 healthy infants as controls. Genomic DNA was extracted from peripheral venous blood leukocytes using phenol chloroform methodology. Polymerase chain reaction was used to amplify the multidrug resistance protein 3 (MDR3) R652G fragment, and products were sequenced using the ABI 3100 Sequencer.
Results: The R652G single nucleotide polymorphism (SNP) was significantly more frequent in healthy infants (allele frequency 8.0%) than in patients (allele frequency 2.60%) (P < 0.05), odds ratio, 0.29; 95% confidence interval, 0.12-0.84. The conjugated bilirubin in patients with the AG genotype was significantly lower than in those with the AA genotype (44.70 +/- 6.15 micromol/L vs 95.52 +/- 5.93 micromol/L, P < 0.05).
Conclusion: MDR3 R652G is negatively correlated with idiopathic infant cholestasis. Children with the R652G SNP in Guangxi of China may have reduced susceptibility to infant intrahepatic cholestasis.