Systematic evaluation of association between the microsomal glutathione S-transferase 2 common variation and psoriasis vulgaris in Chinese population

Genetic Interactions of Phase II Xenobiotic-Metabolizing Enzymes GSTO1 and GCLC in Relation to Alcohol Abuse and Psoriasis Risk

The present pilot study aimed to investigate whether common single nucleotide polymorphisms (SNPs) in the gene encoding glutathione S-transferase omega 1 (GSTO1), both individually and in combination with variants of the catalytic subunit of the glutamate cysteine ligase (GCLC) gene and environmental risk factors, are associated with the risk of psoriasis. The research included a total of 944 participants, comprising 474 individuals diagnosed with psoriasis and 470 healthy control subjects. Five common SNPs in the GSTO1 gene-specifically, rs11191736, rs34040810, rs2289964, rs11191979, and rs187304410-were genotyped in the study groups using the MassARRAY-4 system. The allele rs187304410-A (OR = 0.19, 95% CI 0.04-0.86, Pperm = 0.02) and the genotype rs187304410-G/A (OR = 0.19, 95% CI 0.04-0.85, Pperm = 0.01) were found to be associated with psoriasis in females. The model-based multifactor dimensionality reduction approach facilitated the identification of higher-order epistatic interactions between the variants of the GSTO1 and GCLC genes (Pperm < 0.0001). These interactions, along with the risk factor of alcohol abuse, collectively contribute to the pathogenesis of psoriasis. This study is the first to demonstrate that polymorphisms in the GSTO1 gene, both individually and in combination with variants of the GCLC gene and alcohol abuse, are associated with an increased risk of psoriasis.

Polymorphisms of the GCLC Gene Are Novel Genetic Markers for Susceptibility to Psoriasis Associated with Alcohol Abuse and Cigarette Smoking

The aim of this pilot study was to investigate whether single nucleotide polymorphisms (SNP) in the gene encoding the catalytic subunit of glutamate cysteine ligase (GCLC) are associated with the risk and clinical features of psoriasis. A total of 944 unrelated individuals, including 474 patients with a diagnosis of psoriasis and 470 healthy controls, were recruited for the study. Six common SNPs in the GCLC gene were genotyped using the MassArray-4 system. Polymorphisms rs648595 (OR = 0.56, 95% CI 0.35-0.90; Pperm = 0.017) and rs2397147 (OR = 0.54, 95% CI 0.30-0.98; Pperm = 0.05) were associated with susceptibility to psoriasis in males. In the male group, diplotype rs2397147-C/C × rs17883901-G/G was associated with a decreased risk of psoriasis (FDR-adjusted p = 0.014), whereas diplotype rs6933870-G/G × rs17883901-G/G (FDR-adjusted p = 0.045) showed an association with an increased disease risk in females. The joint effects of SNPs with tobacco smoking (rs648595 and rs17883901) and alcohol abuse (rs648595 and rs542914) on psoriasis risk were observed (Pperm ≤ 0.05). We also found multiple sex-independent associations between GCLC gene polymorphisms and various clinical features such as earlier disease onset, the psoriatic triad, and specific localizations of skin lesions. The present study is the first to show that polymorphisms of the GCLC gene are significantly associated with the risk of psoriasis and related to its clinical features.

Glutathione S-Transferase M1 and T1 Gene Polymorphisms in Patients with Chronic Plaque-Type Psoriasis: A Case-Control Study

OBJECTIVE

To determine the role of glutathione S-transferase (GST) isoenzyme polymorphisms as susceptibility factors in patients with psoriasis in a Turkish cohort.

SUBJECTS AND METHODS

In this case-control study, 105 patients with plaque-type psoriasis and 102 healthy controls were recruited from the dermatology outpatient clinics of two university hospitals. Genomic DNA was extracted from whole blood using a DZ DNA isolation kit. Multiplex PCR was used to determine GSTM1 and GSTT1 polymorphisms in the isolated DNAs.

RESULTS

Of the 150 patients with psoriasis, 83 (79%) were identified with the GSTT1 genotype and 22 (21%) with the null genotype. Of the 102 patients in the control group, 69 (67.6%) subjects were identified with the GSTT1 genotype and 33 (32.4%) with the null genotype. There was no significant difference between the patient and control groups (p = 0.063). Regarding the GSTM1 polymorphism, 54 (51.4%) patients were identified with this genotype and 51 (48.6%) with the null genotype; in the control group, 50 (49%) were identified with this genotype and 52 (51%) with the null genotype. Again there was no statistically significant difference between the groups (p = 0.957).

CONCLUSION

In this Turkish cohort of patients with psoriasis, neither GSTT1 nor GSTM1 polymorphisms were associated with disease susceptibility. Larger studies with a wider range of GST isoenzyme are needed.

Psoriasis: genetic associations and immune system changes

Psoriasis is a common inflammatory skin disease characterized by infiltration of inflammatory cells into the epidermis and altered keratinocyte differentiation. Psoriasis is currently thought of as a T-cell mediated 'Type-1' autoimmune disease. Gene expression changes in psoriasis lesions have been well documented, and strongly support an important role for tumor necrosis factor and interferon gamma signal pathways in its pathogenesis. The strongest genetic determinant of psoriasis identified to date lies within the class I region of the multiple histocompatibility locus antigen cluster, although its low penetrance implicates a requirement for other genetic risk factors. Multiple genome-wide linkage and an increasing number of association studies have been carried out, leading to multiple linkage peaks, and the identification of potential low risk variants. A number of these variants lie within genes encoding components of the immune system. However, the functional relationships between predisposing genetic variation is unclear, and presumably involves genetic susceptibility factors affecting both immune cell activation and keratinocyte differentiation. The interaction of environmental trigger factors with genetic effects is also not understood, but provide further evidence for the complex basis of this disease.