Among the 6 patients with wild-type UGT1A1*28, 1 and 4 patients experienced grade 4 leukopenia and neutropenia, and another patient experienced grade 4 thrombocytopenia, while among the 4 patients with heterozygous UGT1A1*28, 1 patient experienced grade 4 neutropenia. The gene discussed is UGT1A1; the disease is Decreased total neutrophil count.