UGT1A1 and hemochromatosis: However, some conditions, including Crigler-Najjar syndrome (UGT1A1) and HFE-related hemochromatosis (HFE), were associated with high-frequency, low-penetrance variants, specifically c.1091C > T (p.Pro364Leu) in UGT1A1 and c.187C > G (p.His63Asp) in HFE. When these low-penetrance variants were excluded, the carrier rate was reduced to 1/444.