Additional exploratory analyses based on biological validity or a “combined rank” suggest dynamic methylation of several other genes to be potentially involved in treatment response mechanisms of PD, among them the Zinc Finger Protein 622 (ZFP622) gene and the SLC43A2 gene coding for the essential amino acid transporter LAT4, which have not been implicated in mental disorders before. The gene discussed is SLC43A2; the disease is mental disorder.