Association of monoamine-synthesizing genes with the depression tendency and personality in chronic fatigue syndrome patients

Abstract

AimsTyrosine hydroxylase (TH) and GTP cyclohydrolase I (GCH) are the rate-limiting enzymes for the biosynthesis of catecholamines and tetrahydrobiopterin (BH4), respectively. Since catecholamines and BH4 are thought to be involved in the pathophysiology of CFS, we explored the genetic factors that influence CFS development and examined the possible association between the SNPs of the TH and GCH genes and the various characteristics of CFS patients. Main methodsAfter drawing venous blood from CFS patients and controls, genomic DNA was then extracted from whole blood in accordance with standard procedures. Digestion patterns of the PCR products were used for genotyping the SNPs of GCH (rs841; C+243T) and TH (rs10770141; C−824T). We also performed questionnaires consisting of fatigue-scale and temperament and character inventory scale (TCI) to CFS patients. Key findingsOur results demonstrated that the allele differences for the GCH and TH SNPs were not associated with CFS patients. We did find that the GCH gene with the C+243T polymorphism affected harm avoidance, while the TH gene with the C−824T polymorphism affected persistence in the CFS patients. The concept of persistence has been linked to specific personality, such as perfectionism, in CFS. SignificanceOur results suggest that the biosynthetic pathways of the monoamine neurotransmitters that are mediated by TH and GCH might be associated with the CFS clinical findings, because persistence is one of the typical personality traits observed in CFS and patients with major depressive disorder exhibit a higher harm avoidance score.