Therefore, the genetic variant SLCO1B3 and/or SLCO1B1 may enhance the induction of clozapine‐associated neutropenia via a pharmacokinetic mechanism because the liver‐specific organic anion transporter polypeptides (OATPs), SLCO1B1 and SLCO1B3, mediate the basolateral uptake of organic anions in hepatocytes. The gene discussed is SLCO1B1; the disease is Decreased total neutrophil count.