Single-nucleotide polymorphisms of uracil-processing genes affect the occurrence and the onset of recurrent depressive disorder

Piotr Czarny; Paulina Wigner; Justyna Strycharz; Cezary Watala; Ewa Swiderska; Ewelina Synowiec; Piotr Galecki; Monika Talarowska; Janusz Szemraj; Kuan-Pin Su; Tomasz Sliwinski

doi:10.7717/peerj.5116

Single-nucleotide polymorphisms of uracil-processing genes affect the occurrence and the onset of recurrent depressive disorder

PeerJ. 2018 Jun 26:6:e5116. doi: 10.7717/peerj.5116. eCollection 2018.

Authors

Affiliations

¹ Department of Medical Biochemistry, Medical University of Lodz, Lodz, Poland.
² Laboratory of Medical Genetics, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland.
³ Department of Haemostatic Disorders, Medical University of Lodz, Lodz, Poland.
⁴ Department of Adult Psychiatry, Medical University of Lodz, Lodz, Poland.
⁵ Department of Psychiatry and Mind-Body Interface Laboratory (MBI-Lab), China Medical University Hospital, Taichung, Taiwan.

Abstract

Depressive disorders (DD) are known to be associated with increased DNA damage, the impairment of DNA damage repair, and the presence of single-nucleotide polymorphisms (SNPs) in DNA damage repair genes. Some indirect evidence also suggests that uracil metabolism may be disrupted in depressed patients. Therefore, the current study genotypes three SNPs localized in genes encoding uracil-processing proteins: two glycosylases, i.e., UNG g.7245G>C (rs34259), SMUG1 c.-31A>G (rs3087404), and dUTPase, i.e., DUT g.48638795G>T (rs4775748). The polymorphisms were analyzed in 585 DNA samples (282 cases and 303 controls) using TaqMan probes. The G/G genotype and G allele of UNG polymorphism decreased the risk of depression, while the G/C genotype and C allele of the same SNP increased it. It was also found that G/G carriers had their first episode significantly later than the heterozygotes. Although there was no association between the occurrence of depression and the SMUG1 SNP, a significant difference was found between the homozygotes regarding the onset of DD. In conclusion, the SNPs localized in the uracil-processing genes may modulate the occurrence and the onset of depression, which further supports the hypothesis that impairment of DNA damage repair, especially base-excision repair, may play an important role in the pathogenesis of the disease.

Keywords: DNA repair; Depression; Gene polymorphism; Oxidative stress; Uracil metabolism.

Grants and funding

This work was supported by the Medical University of Lodz, Poland [Research Program No. 502-03/6-086-01/502-64-104]. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.