It declined significantly as the concentrations of urea (β = −0.347, p < 0.001), creatinine (β = −0.699, p = 0.005), uric acid (β = −0.184, p = 0.016), β2-microglobulin (β = −0.432, p < 0.001), and parathormone (β = −0.209, p = 0.006) increased in HD patients. The gene discussed is HLA-G; the disease is Huntington disease.