The results of previous studies indicated that patients with UGT1A1 homozygous*28/*28 genotype are at a higher risk of developing neutropenia while on SG therapy, and therefore patients known to have UGT1A1*28 homozygosity should be monitored closely (Bardia et al., 2021a; Rugo et al., 2021; Rugo et al., 2022a). The gene discussed is UGT1A1; the disease is Decreased total neutrophil count.