PTPN22 C1858T and the risk of psoriasis: a meta-analysis

Evaluation of NLRP3 (rs10754558) and PTPN22 (1858C/T) (rs2476601) Functional Polymorphisms in Psoriasis Susceptibility in Egypt

BACKGROUND

Psoriasis is a complex autoimmune multifactorial disease induced by interaction of environmental and genetic factors. This research aimed to clarify the association of NLRP3 (rs10754558) and PTPN22 (1858C/T) (rs2476601) polymorphisms with susceptibility to psoriasis.

METHODS

This case-control study involved 150 patients diagnosed with psoriasis and 100 age- and gender-matched apparently healthy individuals. NLRP3 (rs10754558) polymorphism was done by real time PCR and PTPN22 1858C/T (rs2476601) genotype was identified by tetra-primer amplification refractory mutation system-polymerase chain reaction (PCR) method.

RESULTS

The genotypes distribution of NLRP3 (rs10754558) were significantly associated with psoriasis (p<0.0001). Whereas for PTPN22 (1858C/T) (rs2476601), no significance was found (p=0.09). NLRP3 (rs10754558) GC genotype revealed a significant association with psoriasis (p<0.0001), mainly among male (p=0.004) patients with mild psoriasis (p=0.001) and affected extremities (p=0.0001).

CONCLUSION

We can conclude that the NLRP3 (rs10754558) GC genotype may play a role in psoriasis susceptibility among male Egyptian populations with affected extremities. Future studies must evaluate its role in the prevention or the treatment of psoriasis.

Role of Protein Tyrosine Phosphatase (PTPN22) Gene [C1858T] Functional Variant in Genetic Susceptibility of Psoriatic Arthritis in Kuwaiti Arabs

Background:

Psoriatic arthritis (PsA) is a chronic, systemic inflammatory arthritic disease characterized by joint inflammation that is associated with cutaneous psoriasis, and can lead to pain, swelling, or stiffness in one or more joints. It results from a complex interplay between genetic, immunologic and environmental factors. A functional variant [C1858T] in the protein tyrosine phosphatase (PTPN22) gene, which encoded Arg620Trp in the lymphoid protein tyrosine phosphatase (LYP) has been shown to be a negative regulator of T-cell activation.

Objective:

The objective of this study was to investigate an association between PTPN22 gene [C1858T] functional variant and PsA in Kuwaiti patients.

Methods:

We have investigated the association of PTPN22 gene functional variant in 102 Kuwaiti patients with psoriatic arthritis and compared it to that in 214 healthy controls. The genotypes for the PTPN22 gene [C1858T] variant were determined by using a PCR-RFLP method and confirmed by DNA sequence analysis.

Results:

The frequency of homozygous variant genotype (TT) was found to be significantly higher in PsA patients compared to that in the controls (p <0.0001). Collectively, the variant genotype was detected in homozygous and heterozygous combinations in 30% patients (p <0.0001) compared to 16% in the controls. The frequency of variant genotype was found to be highest in the early-onset PsA patients (age >25-34y). No correlation was detected between the variant genotype (TT) and gender in the Kuwaiti PsA patients.

Conclusion:

Our data show a significant association of PTPN22 gene functional variant [C1958T] with PsA in Kuwaiti patients and highlight its role in determining the genetic susceptibility along with other factors.

Association of Functional Polymorphism in Protein Tyrosine Phosphatase Nonreceptor 22 (PTPN22) Gene with Vitiligo

The protein tyrosine phosphatase nonreceptor 22 (PTPN22) is associated with susceptibility to autoimmune diseases. The functional polymorphism in PTPN22 at 1857 is a strong risk factor for vitiligo susceptibility in Europeans; however, controversy exits in other populations. Present study was aimed to determine whether the PTPN22 C1857T polymorphism confers susceptibility to vitiligo in Saudi Arabians. Genomic DNA was extracted and amplified using tetra primer amplification-refractory mutation system polymerase chain reaction (ARMS-PCR) method. The frequencies of allele T and genotype CT of PTPN22 C1858T polymorphism were significantly higher, whereas those of allele C and genotype CC were lower in patients as compared with controls (P < 0.0001). The genotype TT was absent in both the patients and controls. It is concluded that PTPN22 C1858T polymorphism is strongly associated with vitiligo susceptibility. However, additional studies are warranted using large number of samples from different ethnicities and geographical areas.

The Contribution of PTPN22 to Rheumatic Disease

One of the unresolved questions in modern medicine is why certain individuals develop a disorder such as rheumatoid arthritis (RA) or lupus, while others do not. Contemporary science indicates that genetics is partly responsible for disease development, while environmental and stochastic factors also play a role. Among the many genes that increase the risk of autoimmune conditions, the risk allele encoding the W620 variant of protein tyrosine phosphatase N22 (PTPN22) is shared between multiple rheumatic diseases, suggesting that it plays a fundamental role in the development of immune dysfunction. Herein, we discuss how the presence of the PTPN22 risk allele may shape the signs and symptoms of these diseases. Besides the emerging clarity regarding how PTPN22 tunes T and B cell antigen receptor signaling, we discuss recent discoveries of important functions of PTPN22 in myeloid cell lineages. Taken together, these new insights reveal important clues to the molecular mechanisms of prevalent diseases like RA and lupus and may open new avenues for the development of personalized therapies that spare the normal function of the immune system.

Cannabinoid Signaling in the Skin: Therapeutic Potential of the "C(ut)annabinoid" System

The endocannabinoid system (ECS) has lately been proven to be an important, multifaceted homeostatic regulator, which influences a wide-variety of physiological processes all over the body. Its members, the endocannabinoids (eCBs; e.g., anandamide), the eCB-responsive receptors (e.g., CB₁, CB₂), as well as the complex enzyme and transporter apparatus involved in the metabolism of the ligands were shown to be expressed in several tissues, including the skin. Although the best studied functions over the ECS are related to the central nervous system and to immune processes, experimental efforts over the last two decades have unambiguously confirmed that cutaneous cannabinoid ("c[ut]annabinoid") signaling is deeply involved in the maintenance of skin homeostasis, barrier formation and regeneration, and its dysregulation was implicated to contribute to several highly prevalent diseases and disorders, e.g., atopic dermatitis, psoriasis, scleroderma, acne, hair growth and pigmentation disorders, keratin diseases, various tumors, and itch. The current review aims to give an overview of the available skin-relevant endo- and phytocannabinoid literature with a special emphasis on the putative translational potential, and to highlight promising future research directions as well as existing challenges.

Association of PTPN22 gene polymorphism with non-segmental vitiligo in South Indian Tamils

INTRODUCTION

Non-segmental vitiligo (NSV) is a depigmentation skin disease with loss of melanocytes in the skin.

AIM

To evaluate whether the protein tyrosine phosphatase non-receptor type (PTPN22) single nucleotide polymorphism at +1858C/T had any association with non-segmental vitiligo in South Indian Tamils.

MATERIAL AND METHODS

Genomic DNA was extracted using the phenol-chloroform method, and PTPN22 +1858C/T polymorphism was assayed by Taqman 5'allele discrimination assay. Protein levels were quantified by ELISA.

RESULTS

We found that the allelic frequency of variants of PTPN22 (rs2476601) were significantly different between controls and cases showing a vitiligo risk in the South Indian Tamil population. PTPN22 levels were higher in the heterozygous CT genotype in NSV, when compared with that of the major variant CC genotype of rs2476601.

CONCLUSIONS

This study suggests that the heterozygous CT genotype, of the PTPN22 SNP rs2476601, has a strong risk association with non-segmental vitiligo in South Indian Tamils.

The Protein Tyrosine Phosphatase Nonreceptor 22 (PTPN22) R620W Functional Polymorphism in Psoriasis

Background:

Psoriasis is a complex autoimmune disease caused by the interaction of genetic and environmental factors. PTPN22 gene polymorphism has been reported to affect psoriasis susceptibility; however, no data are available for Middle Eastern populations.

Objective:

The aim of this study was to investigate the association of PTPN22 (1858C/T) R620W polymorphism with psoriasis in a Saudi cohort.

Methods:

Saudi subjects (n = 306) including patients with psoriasis (n = 106) and matched controls (n = 200) were studied for PTPN22 variants using tetra-primer amplification refractory mutation system-polymerase chain reaction method. The frequencies of alleles and genotypes of PTPN22 (1858C/T) polymorphism were compared between patients and controls.

Results:

The frequency of CT genotype of PTPN22 (1858C/T) polymorphism was significantly higher, whereas that of CC genotype was lower in patients with psoriasis than in controls (P < .001, relative risk [RR] = 7.151). The homozygous genotype TT was absent in both the patients and healthy controls. The frequency of allele T encoding tryptophan (W) was significantly increased (P < .001, RR = 5.76), whereas that of allele C encoding arginine (R) decreased in psoriasis cases as compared with controls (P < .001, RR = 0.173) indicating that individuals carrying allele T are more susceptible to psoriasis than noncarriers.

Conclusions:

PTPN22 (1858C/T) polymorphism is positively associated with susceptibility of psoriasis in Saudis and can be developed as biomarker for evaluating psoriasis risk. However, further studies on PTPN22 polymorphism in larger samples from different geographical areas and ethnicity are warranted.

The genetics of human autoimmune disease: A perspective on progress in the field and future directions

Progress in defining the genetics of autoimmune disease has been dramatically enhanced by large scale genetic studies. Genome-wide approaches, examining hundreds or for some diseases thousands of cases and controls, have been implemented using high throughput genotyping and appropriate algorithms to provide a wealth of data over the last decade. These studies have identified hundreds of non-HLA loci as well as further defining HLA variations that predispose to different autoimmune diseases. These studies to identify genetic risk loci are also complemented by progress in gene expression studies including definition of expression quantitative trait loci (eQTL), various alterations in chromatin structure including histone marks, DNase I sensitivity, repressed chromatin regions as well as transcript factor binding sites. Integration of this information can partially explain why particular variations can alter proclivity to autoimmune phenotypes. Despite our incomplete knowledge base with only partial definition of hereditary factors and possible functional connections, this progress has and will continue to facilitate a better understanding of critical pathways and critical changes in immunoregulation. Advances in defining and understanding functional variants potentially can lead to both novel therapeutics and personalized medicine in which therapeutic approaches are chosen based on particular molecular phenotypes and genomic alterations.

Protein tyrosine phosphatase PTPN22 +1858C/T polymorphism is associated with active vitiligo

Vitiligo is characterized by a skin depigmentation disorder resulting from an autoimmune response targeting melanocytes. Within the genetic factors involved in the development of the vitiligo immune response, various genes in the major histocompatibility complex (MHC) and non-MHC loci have been considered to be risk factors. The PTPN22 gene encodes for a lymphoid protein tyrosine phosphatase, a regulator of the activation and development of T-cells. The +1858C/T polymorphism has been associated to autoimmune disease susceptibility in different populations and could be implicated in the onset of vitiligo. To assess the possible association between the presence of PTPN22 +1858C/T and vitiligo, 187 patients with vitiligo and 223 control subjects were analyzed in the study. Genomic DNA was isolated using the salting-out method and samples were subjected to polymerase chain reaction-restriction fragment length polymorphism in order to detect the PTPN22 +1858C/T polymorphism. Causal associations were determined by χ² test and their respective odds ratio (OR) was assessed in a 2×2 contingency table. The results showed an association between active vitiligo and the allele T load [P=0.0418; OR, 2.5706; 95% confidence interval (CI), 1.0040-6.5816], and active vitiligo-CT genotype (P=0.0389, OR, 2.6548; 95% CI, 1.0191-6.9156). In conclusion, the present data indicates a possible association between the PTPN22 +1858C/T genotype and a significant susceptibility of developing an active form of vitiligo.

Psoriasis and metabolic syndrome: a systematic review and meta-analysis of observational studies

BACKGROUND

Increasing population-based studies have suggested a relationship between psoriasis and metabolic syndrome.

OBJECTIVE

The objective of this study was to perform a systematic review and meta-analysis that synthesizes the epidemiologic associations between psoriasis and metabolic syndrome.

METHODS

We searched for observational studies from MEDLINE, EMBASE, and Cochrane Central Register from Jan 1, 1980 to Jan 1, 2012. We applied the Meta-Analysis of Observational Studies in Epidemiology (MOOSE) guidelines in the conduct of this study.

RESULTS

We identified 12 observational studies with a total of 1.4 million study participants fulfilling the inclusion criteria, among whom 41,853 were patients with psoriasis. Based on random-effects modeling of cross-sectional and case-controlled studies, the pooled odds ratio (OR) for metabolic syndrome among patients with psoriasis was 2.26 (95% confidence interval [CI] 1.70-3.01) compared with the general population. Visual inspection of a funnel plot and formal analysis with the Egger test suggested publication bias and absence of small studies in the published literature (P = .03). A dose-response relationship was also observed between psoriasis severity and prevalence of metabolic syndrome.

LIMITATIONS

No studies to date have assessed incidence of metabolic syndrome among patients with psoriasis.

CONCLUSIONS

Compared with the general population, psoriasis patients have higher prevalence of metabolic syndrome, and patients with more severe psoriasis have greater odds of metabolic syndrome than those with milder psoriasis.