UGT1A1 and Hyperbilirubinemia: No significant changes in the ALT, AST, and GGT levels were observed.<h4>Conclusions</h4>The risk of severe hyperbilirubinemia during ATV treatment is minimal for patients without UGT1A1*28 and no more than one additional risk factor and for patients with UGT1A1*28 and no additional risk factors; patients with homozygous genotype UGT1A1*28 are at the highest risk.