UGT1A1 and kernicterus: In fact, consequent to the absence of Ugt1a1 bilirubin-glucuronidation activity in Ugt1-/- mice [16], total plasma bilirubin levels rise immediately after birth leading to important cerebellar damage, cerebellar hypoplasia and early death by kernicterus, with 50% mortality at post-natal day 11 (P11) and no survivors after P14 [17].