UGT1A6 and cerebellar ataxia: Carriers of UGT1A6 19T > G, 552A > C, and 541A > G alleles displayed increased UGT enzyme activity compared with wild-type carriers, whereas UGT1A6 552A > C carriers showed a longer elimination half-life and a lower clearance rate associated with VPA-related adverse drug reactions, such as ataxia, liver damage, metabolic changes, tremor, hallucinations, pancreatitis, and weight gain (Goey et al., 2016) (Table 4).