After using an optimal serum FGF21 cutoff of 437.57 pg/mL calculated by the Youden index for predicting the occurrence of death, the 388 HD patients in this cohort were divided into high FGF21 group (FGF21 > 437.57 pg/mL) and low FGF21 group (FGF21 ≤ 437.57 pg/mL), respectively. The gene discussed is FGF21; the disease is Huntington disease.