While in our study, serum FGF21 level of HD patients was 3–5 times higher than that in control group and this huge increase may mask the impact of diabetes on FGF21; (2) the independent correlation between diabetes and FGF21 can also be diminished by the high incidence of secondary glucose and lipid metabolic disorders in HD patients. The gene discussed is FGF21; the disease is Huntington disease.