In order to know if the elevated CSF Apo A-IV is specific to HD, we compared CSF Apo A-IV/Alb ratios between 5 controls (0.058 [0.013 to 0.154]) and 5 patients with Guillain–Barré syndrome (0.095 [0.055 to 0.126]) and there was no difference between them. The gene discussed is ALB; the disease is Huntington disease.