Previous experiments have revealed altered brain expression of serotonin receptors 5-HT1A, 5-HT1B, 5-HT2A, 5-HT2C, and 5-HT6 in naïve and WD-challenged KO mice [23] which raises the question as to whether similar abnormalities might be present in peripheral organs. The gene discussed is HTR1A; the disease is Wilson disease.