In serum-free conditions, robust differences occurred between the cells from HD patients and healthy subjects: PDHA1 (+27.3%), IDH1 (+40.5%), SDHB (+31.2%) and SDHC (+21.4%) expressions were higher in HD patients on average than in healthy subjects under serum-free conditions (Table 3B-Column 3). The gene discussed is IDH1; the disease is Huntington disease.