Significant differences of anti-muscarinic cholinergic receptor 4 (anti-M4) antibody concentration was found between ME/CFS patients and healthy donors (p = 0.0029); the median concentration of anti-M4 in ME/CFS patients’ plasma samples was 8.95 ng/ml, while that in healthy donors was 6.45 ng/ml (Figure 3A). The gene discussed is CHRM4; the disease is myalgic encephalomeyelitis/chronic fatigue syndrome.