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). This evidence concerns the gene UGT1A6 and Ataxia.