Analysis of PTPN22 C1858T gene polymorphism in cases with type 1 diabetes of Azerbaijan, Northwest Iran

The Association between PTPN22 SNPs and susceptibility to type 1 diabetes: An updated meta-analysis

Type 1 diabetes (T1D) is a significant global health concern, characterized by the autoimmune destruction of insulin-producing pancreatic β-cells, resulting in lifelong dependence on insulin therapy. Although genetic predisposition plays a crucial role in the pathogenesis of T1D, environmental factors also contribute to its onset and progression. Recent research has identified a number of genetic polymorphisms, particularly in the protein tyrosine phosphatase non-receptor 22 gene (PTPN22), that are strongly associated with an increased risk of T1D and may serve as potential biomarkers for early diagnosis and prevention. Despite this, studies investigating the relationship between PTPN22 rs2476601 and T1D risk have consistently demonstrated an association in certain populations, whereas research on rs1310182 has yielded conflicting and less conclusive results. This study presents an updated meta-analysis of two key PTPN22 polymorphic loci - rs2476601 (C1858T) and rs1310182 (A852G) - with the aim of clarifying their associations with T1D. The analysis revealed a significant association between PTPN22 rs2476601 and an increased risk of T1D. In contrast, no significant correlation was found for rs1310182. These findings suggest that PTPN22 rs2476601 as a marker for T1D susceptibility, offering insights into the development of early intervention strategies. However, further research is required to validate these associations and deepen our understanding of the genetic factors involved in T1D pathogenesis.

Clinical value of the expression levels of protein tyrosine phosphatase non-receptor type 22.6 mRNA in peripheral blood mononuclear cells in Crohn's disease

OBJECTIVE

To explore the relationship between the expression levels of protein tyrosine phosphatase non-receptor type (PTPN) 22.6 mRNA in peripheral blood mononuclear cells (PBMCs) and the disease activity as well as clinical characteristics in Crohn's disease (CD) patients.

METHODS

A total of 480 subjects were enrolled. Data were collected including baseline information, expression levels of PTPN22.6 mRNA in PBMCs for all subjects, C-reactive protein (CRP) levels in serum, clinical characteristics, and disease activity for all patients. Expression levels of PTPN22.6 mRNA in PBMCs, CRP levels in serum, clinical characteristics according to Montreal Classification [8], and Crohn's disease activity index (CDAI) were the primary observation outcomes.

RESULTS

The expression levels of PTPN22.6 mRNA (P = 0.032) in PBMCs and serum CRP levels (P < 0.001) were significantly higher in active CD patients than in inactive CD patients (P = 0.032). Correlation analysis showed that there was a positive correlation between expression levels of PTPN22.6 mRNA and CDAI value (r = 0.512, P = 0.003), as well as expression levels of PTPN22.6 mRNA and CRP levels in the CD group (r = 0.456, P = 0.006). There were significantly higher expression levels of PTPN22.6 mRNA in PBMCs in patients with structuring behavior than that in patients with non-stricturing and non-penetrating (NSNP) behaviors (P = 0.018) and penetrating behaviors (P = 0.024).

CONCLUSIONS

The expression levels of PTPN22.6 mRNA can be used as an indicator to help predict CD diagnosis, disease activity, serum CRP level, and behavior type of CD disease.

PTPN22 and CTLA-4 Polymorphisms Are Associated With Polyglandular Autoimmunity

CONTEXT

Single nucleotide polymorphisms (SNPs) of various genes increase susceptibility to monoglandular autoimmunity. Data on autoimmune polyglandular syndromes (APSs) are scarce.

OBJECTIVE

Evaluate potential associations of eight SNPs with APSs.

SETTING

Academic referral endocrine clinic.

PATIENTS

A total of 543 patients with APS and monoglandular autoimmunity and controls.

INTERVENTION

The SNP protein tyrosine phosphatase nonreceptor type 22 (PTPN22) rs2476601 (+1858); cytotoxic T-lymphocyte‒associated antigen 4 (CTLA-4) rs3087243 (CT60) and rs231775 (AG49); vitamin D receptor (VDR) rs1544410 (Bsm I), rs7975232 (Apa I), rs731236 (Taq I); tumor necrosis factor α rs1800630 (-863); and interleukin-2 receptor alpha rs10795791 were tested by single-base extension in all subjects.

RESULTS

The PTPN22 +1858 allele and genotype distribution were markedly different between APS, type 1 diabetes [T1D; odds ratio (OR): 2.67; 95% confidence interval (CI): 1.52 to 4.68; P = 0.001], Graves disease (GD; OR: 1.94; 95% CI: 1.16 to 3.25; P = 0.011), and controls (OR: 3.31, 95% CI: 1.82 to 6.02; P < 0.001). T-allele carriers' risk for APS was increased (OR: 3.76; 95% CI: 1.97 to 7.14; P < 0.001). T-allele frequency was higher among APS than controls (OR: 3.25; 95% CI: 1.82 to 5.82; P < 0.001), T1D (OR: 2.54; 95% CI: 1.48 to 4.36; P = 0.001), or GD (OR: 1.89; 95% CI: 1.15 to 3.11; P = 0.012). The SNP CTLA-4 CT60 G-allele carriers were more frequent in APS (85%) than controls (78%) (OR: 1.55; 95% CI: 0.81 to 2.99). Combined analysis of CTLA-4 AG49 and CT60 revealed OR 4.89; 95% CI: 1.86 to13.59; P = 0.00018 of the genotype combination AG/GG for APS vs controls. VDR polymorphisms Bsm I, Apa I, and Taq I did not, but the haplotypes differed between APS and controls (P = 0.0011).

CONCLUSIONS

PTPN22 and CTLA-4 polymorphisms are associated with APS and differentiate between polyglandular and monoglandular autoimmunity.

The Potential Role of PTPN-22 C1858T Gene Polymorphism in the Pathogenesis of Type 1 Diabetes in Saudi Population

BACKGROUND

Recent investigations have reported an association between protein tyrosine phosphatase non-receptor type-22 (PTPN-22) gene polymorphism and susceptibility to the development of type 1 diabetes (T1D) in some populations and not in others. In this study, we aimed to investigate the association of PTPN-22 C1858T polymorphism with T1D in Saudi children.

METHODS

A cohort of 372 type 1 diabetic children and 372 diabetes-free subjects was enrolled in the current investigation. The PTPN-22 C1858T polymorphism was identified using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method.

RESULTS

Our data showed that the frequency of CT and TT genotypes of PTPN-22 C1858T was higher in T1D children (17.7% and 4.3%, respectively) compared to healthy controls (4.8% and 1.6%, respectively), and both genotypes were statistically associated with T1D patients (OR = 4.4, 95% CI: 2.55-7.58, p < 0.001; and OR = 3.2, 95% CI: 1.23-8.28, p = 0.017, respectively). Moreover, the 1858T allele was significantly associated with T1D patients compared to the C allele (OR = 3.2, 95% CI: 1.59-6.88, p < 0.001). In addition, the T allele was significantly associated with elevated levels of HbA1c, anti-GAD, and anti-insulin antibodies (p < 0.001) and a lower concentration of C-peptide (p < 0.001) in T1D children.

CONCLUSION

The data presented here suggests that the T allele of PTPN-22 C1858T polymorphism might be a risk factor for T1D development in Saudi children.

Association of HaeIII single nucleotide polymorphisms in the SLC2A1 gene with risk of diabetic nephropathy; evidence from Kurdish patients with type 2 diabetes mellitus

AIMS

Given the growing rate of patients with type 2 diabetes mellitus, uncovering the effects of gene polymorphism on diabetes pathogenesis has attracted a lot of attention. Because glucose transporter 1 is involved in glucose uptake, the polymorphism of this gene may be an important risk factor in type 2 diabetes mellitus or in the progression of diabetes complications such as diabetic nephropathy. As far as the authors are concerned, this study is the first one aiming at evaluating the probable effects of solute carrier family 2 facilitated glucose transporter member 1 (SLC2A1) HaeIII polymorphism on clinical and laboratory outcomes of Kurdish patients with type 2 diabetes mellitus.

METHODS

This study was conducted involving 126 diabetic nephropathy patients and 150 diabetic patients without renal involvement. Serum levels of Cystatin C, fasting blood glucose, creatinine and urinary albumin; levels of glycated hemoglobin and estimated glomerular filtration rate were measured. Moreover, the Hae III polymorphism of SLC2A1 gene was determined by PCR-restriction fragment length polymorphism (RFLP).

RESULTS

The rate of CC genotype was higher (37%) in patients with diabetic nephropathy compared with controls. There were a significant correlation between the CC genotype and risk of diabetic nephropathy. There were significant correlations between genotypes, serum Cystatin C and estimated glomerular filtration rate in patients with diabetic nephropathy.

CONCLUSIONS

The results demonstrated the high frequency of C allele of SLC2A1 HaeIII in Kurdish patients with diabetic nephropathy. It was also found that this polymorphism is a significant risk factor for diabetic nephropathy. The effect of this polymorphism on clinical and laboratory characteristics of diabetic nephropathy patients was significant.

Association study of IL2RA and CTLA4 Gene Variants with Type I Diabetes Mellitus in children in the northwest of Iran

Introduction: A variety of genetic predisposing factors and environmental factors are known to influence the pathogenesis of type-1 diabetes (T1D). This study intended to investigate the association of cytotoxic T-lymphocyte associated protein 4 (CTLA4) and interleukin 2 receptor subunit alpha (IL2RA) gene polymorphisms with type 1 diabetes in children of northwest of Iran. Methods: Genomic DNA was extracted by salting-out method. PCR amplification and direct sequencing methods were used for genotyping of CTLA4 (exon 1) and IL2RA (intron 1) genes in all patients and controls. SNPStats was used to calculate odds ratios (ORs), 95% confidence intervals (CIs), and p values. Results: In this study, the frequency of G allele and GG genotype of CTLA-4 (+49A/G) polymorphism in T1D patients were significantly different from those in the controls (26% vs. 11%, p = 0.006). Moreover, a significant difference was observed between patients and control group in the allele frequencies of the new SNP (chr2:203868145) that was identified in exon one of CTLA4 (14% vs. 3%, p = 0.006). The results showed that the GG homozygous genotype of +49 A>G was associated with increased glycemic level in T1D patients in the study population (95% CI = 10.47, p = 0.0067). However, no significant association was found between IL2RA (ss52580101C>A) polymorphism and T1D patients (2% vs. 4%, p = 0.41). Conclusion: The results further support the association of T1D with +49A>G SNP in the CTLA4 gene in the population of northwest of Iran. However, no significant relationship was observed between ss52580101C>A polymorphism of IL2RA gene and T1D in this study.