CTLA-4 (+49A/G) polymorphism and type-1 diabetes in Turkish children

Computational analysis of structural and functional evaluation of the deleterious missense variants in the human CTLA4 gene

CTLA-4 is an immune checkpoint receptor that negatively regulates the T-cell function expressed after T-cell activation to break the immune response. The current study predicted the genomic analysis to explore the functional variations of missense SNPs in the human CTLA4 gene using PolyPhen2, SIFT, PANTHER, PROVEAN, Fathmm, Mutation Assessor, PhD-SNP, SNPs&GO, SNAP2, and MutPred2. Phylogenetic conservation protein was predicted by ConSurf. Protein structural analysis was carried out by I-Mutant3, MUpro, iStable2, PremPS, and ERIS servers. Molecular dynamics trajectory analysis (RMSD, RMSF, Rg, SASA, H-bonds, and PCA) was performed to analyze the dynamic behavior of native and mutant CTLA-4 at the atomic level. Our in-silico analysis suggested that C58S, G118R, P137Q, P137R, P137L, P138T, and G146L variants were predicted to be the most deleterious missense variants and highly conserved residues. Moreover, the molecular dynamics analysis proposed a decrease in the protein stability and compactness with the P137R and P138T highlighting the impact of these variants on the function of the CTLA-4 protein.Communicated by Ramaswamy H. Sarma.

CTLA-4 CT-60 A/G and CTLA-4 1822 C/T Gene Polymorphisms in Indonesians with Type 1 Diabetes Mellitus

Introduction

CTLA-4 gene polymorphism plays an important role in children with type 1 diabetes mellitus (T1DM). However, data on this subject vary among different races and ethnics.

Purpose

To analyze CTLA-4 CT-60 A/G and CTLA-4 1822 C/T gene polymorphism among children with T1DM compared to control.

Patients and Methods

The CTLA-4 CT-60 A/G and CTLA-4 1822 C/T gene polymorphism in children with T1DM using polymerase chain reaction-restriction fragment length polymorphism in 25 T1DM and 25 controls. The inclusion criteria were patients regularly controlled at the Pediatric Endocrine Outpatient Clinic of Dr. Soetomo Hospital, aged 4-18 years and willing to join this study and the exclusion criteria were T1DM patients hospitalized in the pediatric intensive care unit. In the control group, the inclusion criteria were healthy children, aged 4-18 years and willing to join this study. The exclusion criteria included children with ongoing infection, history of other autoimmune diseases, allergies, or malignancy.

Results

The mean age was 12.48 years old, and the mean of T1DM onset was 9.28 years old. The CTLA-4 1822 T allele observed in 62% T1DM and 56% in control (p = 0.388, OR = 0.78, 95% CI = 0.44-1.37) and CTLA-4 CT-60 G allele observed in 52% T1DM and 58% in control (p = 0.393, OR = 1.27, 95% CI = 0.73-2.22). The C/T genotypes was significantly higher in control group (p = 0.045, OR = 3.27, 95% CI = 1.00-10.62). The A/G genotypes was commonly found in control group (p = 0.765, OR = 1.20, 95% CI = 0.37-3.86). The Javanese was the dominant ethnic group in our study.

Conclusion

The frequency of CTLA-4 CT-60 A/G polymorphism almost equivalent in T1DM and control group. However, CTLA-4 1822 C/T polymorphism was more prevalent in the control group; thus, this genotype may have a protective effect against T1DM.

Childhood body size directly increases type 1 diabetes risk based on a lifecourse Mendelian randomization approach

The rising prevalence of childhood obesity has been postulated as an explanation for the increasing rate of individuals diagnosed with type 1 diabetes (T1D). In this study, we use Mendelian randomization (MR) to provide evidence that childhood body size has an effect on T1D risk (OR = 2.05 per change in body size category, 95% CI = 1.20 to 3.50, P = 0.008), which remains after accounting for body size at birth and during adulthood using multivariable MR (OR = 2.32, 95% CI = 1.21 to 4.42, P = 0.013). We validate this direct effect of childhood body size using data from a large-scale T1D meta-analysis based on n = 15,573 cases and n = 158,408 controls (OR = 1.94, 95% CI = 1.21 to 3.12, P = 0.006). We also provide evidence that childhood body size influences risk of asthma, eczema and hypothyroidism, although multivariable MR suggested that these effects are mediated by body size in later life. Our findings support a causal role for higher childhood body size on risk of being diagnosed with T1D, whereas its influence on the other immune-associated diseases is likely explained by a long-term effect of remaining overweight for many years over the lifecourse.

The rise in type 1 diabetes is thought to be related to increased childhood obesity, but this relationship is not well understood. In this study, the authors utilize Mendelian randomization to separate the direct and indirect effects of childhood body size on risk of type 1 diabetes and 7 other immune-associated disease outcomes.

Association of Cytotoxic T-Lymphocyte Antigen-4 Gene Polymorphism with Type 1 Diabetes Mellitus: In silico Analysis of Biological Features of CTLA-4 Protein on Ethiopian Population

BACKGROUND

T1DM is a chronic organ-specific T-cell-mediated autoimmune disease characterized by the selective destruction of β-cells in the islets of Langerhans, resulting in insulin deficiency and hyperglycemia. Genes for cytotoxic T lymphocyte-associated antigen 4 have been hypothesized as possible contender genes for T1DM vulnerability. However, it has not been studied in the Ethiopian population yet.

OBJECTIVE

The aim of the study was to investigate CTLA-4 exon 1 was linked to A49G polymorphism with T1DM and its biological features of CTLA-4 among T1DM patients, in Ethiopia.

METHODS

A case-control study was done from December 2019 to March 2020 on 210 study participants (105 T1DM patients and 105 healthy controls). Polymerase Chain Reaction amplification with forward and reverse primers was followed by restriction fragment length polymorphism and gel electrophoresis to determine gene polymorphism. Bioinformatics data of SNP was retrieved from National Centers for Biotechnology Information databases. The chi-square test and logistic regression were used. Statistical significance was defined as a P-value of less than 0.05.

RESULTS

The CTLA-4 (+A49G) gene polymorphism was observed on 56 (26.7%) study participants, 39 (18.57%) of T1DM patients, and 17 (0.08%) were controls. In T1DM and controls, the frequency of the A allele was 73.3% and 89.5%, while the G allele was 26.7% and 10.5%, respectively. The G allele was found to be associated with T1DM (OR=3.1; 95% CI, 1.82 -5.32; P=0.001). Statistical analysis revealed an association between the likelihood of T1DM and GG genotype of the CTLA-4 (+A49G) gene polymorphism (OR=3.11; 95% CI, 1.37-10.90; P=0.01). Further in silico analyzed the SNP to assess its biological features.

CONCLUSION

The study showed as CTLA-4 (+A49G) gene polymorphism is linked with T1DM in the Ethiopian population.

Relation Between Zinc and Thyroid Hormones in Humans: a Systematic Review

The aim of this study was to systematically evaluate the relation between zinc and the thyroid hormones in humans. The search for articles was conducted using the Pubmed, Scopus, Cochrane Central Register of Controlled Trials (CENTRAL), and ScienceDirect databases on October 21 and 22, 2019, by two authors independently. The recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) were followed in the conduct of this review. The Cochrane Collaboration tool was used to assess the risk of bias of the trials included in this review. After the screening of the articles, eight studies that assessed the effects of zinc supplementation on thyroid hormone concentrations and ten studies that assessed the relationship between blood zinc concentrations and thyroid hormones were included in this systematic review. Although cross-sectional and case-control studies have shown a relationship between zinc deficiency and thyroid, the data from this systematic review provides inconclusive evidence with respect to the effects of zinc supplementation on thyroid hormone concentrations due to the divergence of the research found by the authors that only reports findings in patients suffering from some kind of disease, which cannot be generalized to the average human population.

Obesity and Monitoring Iodine Nutritional Status in Schoolchildren: is Body Mass Index a Factor to Consider?

Background: The frequency of overweight (OW) and obese (OB) children has increased worldwide, particularly in economically developed countries. No studies have been conducted to verify whether the increasing frequency of OW and obesity in schoolchildren may affect the evaluation of iodine nutritional status in populations. The aim of this study was to verify whether urinary iodine concentration (UIC), thyroid volume (TV), and thyroid hypoechoic pattern may be affected by body mass index (BMI) in schoolchildren. Methods: The children included in this study (aged 11-13 years) were a part of the schoolchildren recruited in the second nationwide survey (period 2015-2019) conducted in Italy to monitor by law (Atto di Intesa Stato-Regioni February 26, 2009) the nationwide iodine prophylaxis program. Specifically, 1281 schoolchildren residing in iodine-sufficient areas (IS group) and 384 children residing in a still mildly iodine-deficient area (ID group) were recruited between January and March 2015 in the first-degree secondary state schools. In all the children, spot UIC was measured, thyroid ultrasound was performed to evaluate TV, and hypoechogenicity was assessed to indirectly evaluate iodine-associated thyroid autoimmunity. Results: The frequency of OW, OB, and adequate weight (AW) children was similar in the IS and ID groups at any age. After adjusting for sex and age, the regression analysis showed lower UIC values in OB children than in AW children of the IS group (beta coefficient = -34.09 [95% confidence interval -65.3 to -2.8]), whereas no significant differences were observed in the ID group. In both the IS and ID groups, the distribution of TV in AW children was significantly shifted toward lower values in comparison to the distribution of OB children (p < 0.001 in the IS group; p = 0.012 in the ID group). Furthermore, the frequency of thyroid hypoechogenicity was higher in the ID group than in the IS group (10.9% vs. 6.6%, p = 0.005); however, in both groups, it was significantly lower in AW children than in OB children (p < 0.01). Conclusions: This study for the first time demonstrates that BMI may be a confounding factor in monitoring iodine nutritional status in schoolchildren. Since in Italy as in other Western countries the number of OW and OB children is high, BMI is a factor to consider in monitoring salt iodization programs worldwide.

CTLA-4 (+49A/G) Polymorphism in Type 1 Diabetes Children of Sudanese Population

Background  Type 1 diabetes mellitus (T1DM) is an organ-specific T cell-mediated autoimmune disease, characterized by destruction of pancreatic islets. Cytotoxic lymphocyte antigen-4 ( CTLA-4 ) is a negative regulator of T cell proliferation, thus conferring susceptibility to autoimmunity.

Aims  This study aimed to investigate the association of CTLA-4 +49A/G (rs231775) polymorphism with a risk of T1DM in Sudanese children.

Methods  This a case–control study included 100 children with T1DM, referred to the pediatric clinic at referral pediatric teaching hospital in Gezira State-Sudan. Hundred unrelated healthy controls were recruited from departments in the same hospital. Genomic deoxyribonucleic acid (DNA) was extracted from Ethylenediaminetetraacetic Acid (EDTA)-preserved blood using QIAamp DNA Blood Mini Kit (QIAamp Blood) (QIAGEN; Valencia, CA). The polymerase chain reaction PCR restriction fragment length polymorphism (PCR-RFLP) and sequencing were applied for the CTLA-4 (+49A/G) genotyping. The changes accompanied the polymorphism were evaluated using relevant bioinformatics tools.

Results  The genotype and allele frequencies of the CTLA-4 (+49A/G) polymorphism were significantly different between the patients and controls ( p  = 0.00013 and 0.0002, respectively). In particular, the frequency of the G allele, GG homozygous genotype, and AG heterozygous genotype were significantly increased in patients than in controls ([28% versus 7%, odds ratio (OR) = 5.16, 95% confidence interval [CI] = 2.77–9.65, p  = 0.00] [12% versus 2%, OR = 6.68, CI = 1.46–30.69, p  = 0.01] [32% versus 10%, OR = 4.24, CI = 1.95–9.21, p  = 0.00], respectively). The presence of the G allele (homozygous) showed an influence on the signal peptide polarity, hydrophobicity, and α-helix propensity of the CTLA-protein.

Conclusion  The results further support the association of CTLA-4 (+49A/G) polymorphism and the risk of T1DM in our study population.

Central Hypothyroidism Impairs Heart Rate Stability and Prevents Thyroid Hormone-Induced Cardiac Hypertrophy and Pyrexia

Background: Tachycardia, cardiac hypertrophy, and elevated body temperature are major signs of systemic hyperthyroidism, which are considered to reflect the excessive thyroid hormone (TH) action in the respective peripheral tissues. However, recent observations indicate that the central actions of TH also contribute substantially to cardiovascular regulation and thermogenesis. Methods: In this study, we dissect the individual contributions of peripheral TH action versus the central effects in body temperature regulation and cardiovascular functions by taking advantage of mice lacking the TH transporters monocarboxylate transporter 8 (MCT8) and organic anion transporting polypeptide 1C1 (OATP1C1) (M/O double knock-out [dko]), which exhibit elevated serum triiodothyronine (T3) levels while their brain is in a profoundly hypothyroid state. We compared these animals with wild-type (WT) mice that were treated orally with T3 to achieve similarly elevated serum T3 levels, but are centrally hyperthyroid. For the studies, we used radiotelemetry, infrared thermography, gene expression profiling, Western blot analyses, and enzyme linked immunosorbent assays (ELISA) assays. Results: Our analyses revealed mild hyperthermia and cardiac hypertrophy in T3-treated WT mice but not in M/O dko animals, suggesting that central actions of TH are required for these hyperthyroid phenotypes. Although the average heart rate was unaffected in either model, the M/O dko exhibited an altered heart rate frequency distribution with tachycardic bursts in active periods and bradycardic episodes during resting time, demonstrating that the stabilization of heart rate by the autonomic nervous system can be impaired in centrally hypothyroid animals. Conclusions: Our studies unravel distinct phenotypical traits of hyperthyroidism that depend on an intact central nervous system, and provide valuable insight into the cardiovascular pathology of the Allan-Herndon-Dudley syndrome, a condition caused by the lack of MCT8 in humans.

Autoimmune thyroid disease and type 1 diabetes mellitus: same pathogenesis; new perspective?

Autoimmune thyroid disease (AITD) and type 1 diabetes mellitus (T1DM) are two common autoimmune diseases that can occur concomitantly. In general, patients with diabetes have a high risk of AITD. It has been proposed that a complex genetic basis together with multiple nongenetic factors make a variable contribution to the pathogenesis of T1DM and AITD. In this paper, we summarize current knowledge in the field regarding potential pathogenic factors of T1DM and AITD, including human leukocyte antigen, autoimmune regulator, lymphoid protein tyrosine phosphatase, forkhead box protein P3, cytotoxic T lymphocyte-associated antigen, infection, vitamin D deficiency, and chemokine (C-X-C motif) ligand. These findings offer an insight into future immunotherapy for autoimmune diseases.

The Role of Zinc in Thyroid Hormones Metabolism

Abstract. Thyroid hormones play an important role in body homeostasis by facilitating metabolism of lipids and glucose, regulating metabolic adaptations, responding to changes in energy intake, and controlling thermogenesis. Proper metabolism and action of these hormones requires the participation of various nutrients. Among them is zinc, whose interaction with thyroid hormones is complex. It is known to regulate both the synthesis and mechanism of action of these hormones. In the present review, we aim to shed light on the regulatory effects of zinc on thyroid hormones. Scientific evidence shows that zinc plays a key role in the metabolism of thyroid hormones, specifically by regulating deiodinases enzymes activity, thyrotropin releasing hormone (TRH) and thyroid stimulating hormone (TSH) synthesis, as well as by modulating the structures of essential transcription factors involved in the synthesis of thyroid hormones. Serum concentrations of zinc also appear to influence the levels of serum T3, T4 and TSH. In addition, studies have shown that Zinc transporters (ZnTs) are present in the hypothalamus, pituitary and thyroid, but their functions remain unknown. Therefore, it is important to further investigate the roles of zinc in regulation of thyroid hormones metabolism, and their importance in the treatment of several diseases associated with thyroid gland dysfunction.

Association of CTLA-4 and CD28 Gene Polymorphisms with Type 1 Diabetes in South Indian Population

Each functional gene illustrates the complexity of genetic predisposition to disease; however, it is difficult to bring out these traits with reference to autoimmune diseases like type 1 diabetes (T1D). To find out the genetic contribution of CTLA-4 + 49A/G, CTLA-4 -318C/T and CD28 + 17T/C polymorphisms toward T1D, the present study was performed with 124 T1D patients, 54 siblings and 125 parents including 39 trios in South Indian population. The association and linkage of CTLA-4 + 49A/G, CTLA-4 -318C/T and CD28 + 17T/C polymorphisms with T1D were analyzed and transmission disequilibrium test was performed. CTLA-4 G allele carrying genotypes (GG+AG) showed a higher risk association and can be considered as susceptible to develop T1D among patients with age at diagnosis from 0 to 10 years as compared to siblings (OR = 2.9; p_c = 0.047) and parents (OR = 2.7; p_c = 0.036). On the other hand, a strong protection against the disease (age at diagnosis; 0-10 years) was observed with CTLA-4 + 49AA genotype (OR = 0.37; p_c = 0.036) and combined AA/CC genotype (OR = 0.31; p_c = 0.034) of CTLA-4 + 49A/G and CTLA-4 -318C/T polymorphisms. However, a significant association was not observed between CTLA-4 -318C/T and CD28 + 17T/C polymorphisms and T1D. This family-based study reports a strong association between possible genotypes of CTLA-4 gene polymorphism and T1D in South Indian population, particularly in younger individuals.

Associations between cytotoxic T-lymphocyte-associated antigen 4 gene polymorphisms and diabetes mellitus: a meta-analysis of 76 case-control studies

Background: Several genetic association studies already investigated potential roles of cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) gene polymorphisms in diabetes mellitus (DM), with inconsistent results. Therefore, we performed this meta-analysis to better assess the relationship between CTLA-4 gene polymorphisms and DM in a larger pooled population.

Methods: PubMed, Embase, Web of Science, and CNKI were systematically searched for eligible studies. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to estimate the strength of associations between CTLA-4 gene polymorphisms and DM in all possible genetic models.

Results: A total of 76 studies were finally included in our analyses. Significant associations with susceptibility to type 1 diabetes mellitus (T1DM) were detected for rs231775 (dominant model: P=0.008, OR = 0.83, 95%CI 0.73–0.95; recessive model: P=0.003, OR = 1.27, 95%CI 1.09–1.50; allele model: P=0.004, OR = 0.85, 95%CI 0.77–0.95) and rs5742909 (recessive model: P=0.02, OR = 1.50, 95%CI 1.05–2.13) polymorphisms in overall population. Further subgroup analyses revealed that rs231775 polymorphism was significantly associated with susceptibility to T1DM in Caucasians and South Asians, and rs5742909 polymorphism was significantly associated with susceptibility to T1DM in South Asians. Moreover, rs231775 polymorphism was also found to be significantly associated with susceptibility to type 2 diabetes mellitus (T2DM) in East Asians and South Asians.

Conclusions: Our findings indicated that rs231775 and rs5742909 polymorphisms may serve as genetic biomarkers of T1DM, and rs231775 polymorphism may also serve as a genetic biomarker of T2DM.

A prospective study of adverse effects of antipsychotics in adolescents with schizophrenia during a 6-month follow-up

There is a paucity of follow-up studies of neurological, endocrine, and metabolic adverse effects of antipsychotics in adolescents from low-income and middle-income countries, who have a higher prevalence of obesity and overweight, and could present increased morbidity. A Mexican sample of 86 adolescents with schizophrenia was examined during a 6-month follow-up using the Simpson-Angus, abnormal involuntary movement and Barnes Akathisia rating scales, in addition to a side effects score sheet and other laboratory measures. Binary logistic regression models were used to identify specific variables as predictors of weight gain. Sleep difficulties, restlessness, drowsiness, changes in thyroid hormones, and a linear increase in weight gain were observed. A baseline positive and negative syndrome scale score greater than 97 predicted a 5 kg increase at month 3 (odds ratio: 4.52, 95% confidence interval: 1.5-13.2). The absence of a plateau in weight gain in the present study across the 6-month treatment period and its relationship with illness severity suggests that even longer follow-up time should be examined in future studies in these patient populations.

Cytotoxic T-lymphocyte-associated protein 4 +49A/G polymorphisms contribute to the risk of type 1 diabetes in children: An updated systematic review and meta-analysis with trial sequential analysis

Type 1 diabetes (T1D) is a heritable disease associated with multiple genetic variants. This systematic review and meta-analysis assessed the correlation between cytotoxic T-lymphocyte-associated protein 4(CTLA-4) +49A/G polymorphisms and the risk of T1D in children. The random effects model was used to estimate the related odds ratios (ORs) and 95% confidence intervals (CIs). Trial sequential analysis (TSA) was used to determine whether the currently available evidence was sufficient and conclusive. Our results indicated that CTLA-4 gene polymorphisms significantly increased the risk of childhood T1D in an allelic model (G vs. A: OR=1.33, 95%CI=1.19-1.48; I2=44.0% and P=0.001for heterogeneity) and a codominant model (GG vs. AA: OR=1.75, 95%CI=1.37-2.24; I2=57.5% and P=0.001for heterogeneity; GA vs. AA: OR=1.26, 95%CI=1.09-1.46; I2=40.4% and P=0.036for heterogeneity). Subgroup analysis results indicated that the ORs were higher in the Asian population (ORallelic model=1.60, ORGG vs. AA=2.46 and ORGA vs. AA=1.58) than the Caucasian population (ORallelic model==1.24, ORGG vs. AA=1.55 and ORGA vs. AA=1.19). The TSA results indicated that the evidence of the effect was sufficient. In conclusion, CTLA4 +49A/G polymorphisms increased the risk of T1D in children, and CTLA4 +49A/G can be considered to be a genetic marker for T1D in children.

Associations between serum polybrominated diphenyl ethers and thyroid hormones in a cross sectional study of a remote Alaska Native population

Polybrominated diphenyl ethers (PBDEs) are ubiquitous environmental pollutants. Arctic indigenous peoples are exposed to PBDEs through a traditional diet high in marine mammals. PBDEs disrupt thyroid homeostasis. The aim of this study was to assess the relationship between serum PBDEs and thyroid function in a remote population of St. Lawrence Island Yupik. Serum samples were collected from 85 individuals from St. Lawrence Island, Alaska and measured for concentrations of PBDEs, free and total thyroxine (T4), free and total triiodothyronine (T3), and thyroid stimulating hormone (TSH). The relationships between PBDEs and thyroid hormones were assessed using multiple linear regression fit with generalized estimating equations. Serum concentrations of several Penta-BDE congeners (BDE-28/33, 47, and 100) were positively associated with concentrations of TSH and free T3, while serum concentration of BDE-153 was negatively associated with total T3 concentrations. Both BDE-47 and 153 remained significantly associated with thyroid hormones when BDE-47, BDE-153, and BDE-209 were covariates in the same model. There were no significant relationships between serum concentrations of PBDEs and either free or total T4. Individual PBDEs are associated with thyroid hormones in serum from a remote population of Alaska Natives, and directions of effect differ by congener.

The Relationship between insulin variable number of tandem repeats (INS-VNTR) -23 A/T and cytotoxic Tlymphocyte associated protein-4 (CTLA-4) +49 A/G polymorphisms with islet autoantibodies in persons with diabetes

Background: Both genetic and environmental factors are important in pathogenesis of diabetes. Non HLA (Human Leukocyte Antigen) genes such as INS-VNTR and CTLA-4 in addition of HLA genes have influence on genetic susceptibility for diabetes mellitus. In this study the association of +49 A/G CTLA-4 and -23 A/T INS-VNTR polymorphisms with diabetes and their association with islet autoantibodies were investigated. Methods: Thirty four autoantibody positive adult persons with diabetes mellitus and 39 persons with Type 1diabetes mellitus (T1DM), 40 autoantibody negative Type 2 diabetes mellitus (T2DM) patients and 40 healthy controls were studied using Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) technique. Results: The frequencies of -23 A/T INS-VNTR genotypes were not significantly different among study groups. It was shown that the distribution of the +49A/G CTLA-4 allele and genotype frequencies did not differ between T1DM patients, autoantibody positive adult patients and controls. With increasing CTLA-4 G allele and GG/AG genotypes, the frequency of Glutamic Acid Decarboxylase Autoantibody (GADA), Islet Cell Autoantibody (ICA) and Islet Antigen 2 Antibody (IA2A) positive patients were increased. Conclusion: Our results suggest that susceptibility allele A of -23A/T INS-VNTR does not have any role in the pathogenesis of diabetes in our patients and susceptibility allele G of +49 A/G CTLA-4 if not, has a small role in pathogenesis of diabetes in T1DM and autoantibody positive adult patients and in spite of significant increase in autoantibody negative T2DM group it does not have any role in disease pathogenesis.

CTLA-4 Genetic Variants (rs11571317 and rs3087243): Role in Susceptibility and Progression of Breast Cancer

Background

Dysfunctional regulation at immune checkpoints may lead to escape of the tumor cells and gives a scope to set in the unresolved Breast cancer (BC). The major anti-tumor retort is cell-mediated response which involves T lymphocytes. CTLA-4 (Cytotoxic T lymphocyte associated protein-4) with immune suppressive function and tolerance is associated with various autoimmune diseases and cancers including BC. The present study deals with CTLA-4 gene selected polymorphisms (rs11571317 C/T and rs3087243G/A) to explore their relation with breast cancer susceptibility and progression in BC patients.

Methods

For the present case-control study, we recruited a total of 570 women which include breast cancer patients and healthy control women from south India. Blood samples were collected, genomic DNA was isolated and genotyped by using PCR-RFLP method, and the data were analysed through suitable statistics.

Results

We observed a significant association of rs11571317 with BC in our study group, where CC genotype showed a three-fold increased risk towards BC and CT genotype to be protective. In-silico analyses strengthened our observation revealing the abolition of SP1 binding site in the CTLA-4 promoter by the mutant allele T. The CTLA-4 rs3087243 polymorphism showed an association not with the susceptibility but towards the tumor progression, where GG genotype was coupled with reduced tumor growth (OR = 0.01) and GA (OR = 6.2), AA (OR = 3.4) with increased tumor growth. The T-G haplotype was found to confer protection against breast cancer risk while C-A (OR = 3.6) and T-A (OR = 15.8) haplotypes were associated with disease progression. In-silico analysis for rs3087243 revealed change in threshold values between reference and variant sequences.

Conclusion

The study suggests varied roles of different polymorphisms of CTLA-4 in the aetiopathogenesis of BC. Understanding the mechanism may help in the CTLA-4 based immunotherapy for BC.

Autoimmune thyroid diseases in children

Autoimmune thyroid diseases (AIT) are common in children and may present with a variety of signs and symptoms including: euthyroid goiter, hypothyroidism, or hyperthyroidism. The natural history of AIT may be different in children but in all age groups, there appear to be genetic risk factors and environmental triggers that initiate thyroid autoimmunity. Areas covered: In this review, we summarize recent studies that investigate the genetics and environmental triggers believed to be involved in thyroid autoimmunity. We also discuss the approach and controversies in the treatment of children with AIT. Expert commentary: Much has been learned about the major roles for genetics, cytokines, regulatory lymphocytes, and environmental triggers in CLT but controversies remain.

High Iodine and Salt Intakes and Obesity do not Modify the Thyroid Function in Mexican Schoolchildren

Mexico is considered as a nutritional transition country with a high prevalence of overweight and obesity, and recent studies have reported a high iodine intake in children. Both high iodine intake and obesity have been associated with thyroid dysfunction. Our aim was to assess iodine and salt intake and thyroid function in Mexican schoolchildren with normal weight and obesity. A cross-sectional study was performed during 2012-2013 in schoolchildren from Queretaro, Mexico. Six hundred seventy-eight schoolchildren were evaluated to obtain nutrition status, urinary iodine concentration (UIC) and thyroid volume (TVol). The prevalence of overweight and obesity was 47.3 %, the median UIC was 428 μg/L and TVol was normal in all schoolchildren; however, obese girls had a higher TVol than normal weight at the age of 8, 10 and 12 years. A subsample of schoolchildren was divided in 6-8 and 9-12-year-old groups, in order to compare thyroid function (thyrotropin, free T4, and anti-thyroid antibodies); iodine and salt intake were estimated with 24-h urinary samples. No differences in thyroid function were observed in both age groups. In the 6-8-year-old group, obese schoolchildren had higher iodine intake than normal-weight children (415.5 vs. 269.1 μg/day, p < 0.05), but no differences in salt intake. In contrast, in the 9-12-year-old group, obese schoolchildren had higher salt intake than normal-weight children (6.2 vs. 3.8 g/day, p < 0.05), but no differences in iodine intake. Dietary patterns could explain the differences between both age groups. Further studies are needed to identify the main sources of iodine intake in Mexican populations.

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.

Impact of population admixture on the distribution of immune response co-stimulatory genes polymorphisms in a Brazilian population

Co-stimulatory molecules are essential in the orchestration of immune response and polymorphisms in their genes are associated with various diseases. However, in the case of variable allele frequencies among continental populations, this variation can lead to biases in genetic studies conducted in admixed populations such as those from Brazil. The aim of this study was to evaluate the influence of genomic ancestry on distributions of co-stimulatory genes polymorphisms in an admixed Brazilian population. A total of 273 individuals from the north of Brazil participated in this study. Nine single nucleotide polymorphisms in 7 genes (CD28, CTLA4, ICOS, CD86, CD40, CD40L and BLYS) were determined by polymerase chain reaction-restriction fragment length polymorphism. We also investigated 48 insertion/deletion ancestry markers to characterize individual African, European and Amerindian ancestry proportions in the samples. The analysis showed that the main contribution was European (43.9%) but also a significant contribution of African (31.6%) and Amerindian (24.5%) ancestry. ICOS, CD40L and CD86 polymorphisms were associated with genomic ancestry. However there were no significant differences in the proportions of ancestry for the other SNPs and haplotypes studied. Our findings reinforce the need to apply AIMs in genetic association studies involving these polymorphisms in the Brazilian population.

Polymorphisms of co-inhibitory molecules (CTLA-4/PD-1/PD-L1) and the risk of non-small cell lung cancer in a Chinese population

Lung cancer is a leading cause of cancer-related death in China, with non-small cell lung cancer (NSCLC) comprises the most common form. Co-inhibitory molecules, such as cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), programmed death 1 (PD-1) and its ligand PD-L1, play a key roles in the physiopathological process of tumorigenesis. To investigate whether genetic variations of co-inhibitory molecules are associated with the risk of NSCLC, we analyzed polymorphisms of CTLA-4 (-318, +49), PD-1 (PD-1.1, PD-1.3, PD-1.5, PD-1.9) and PD-L1 (+8293) in a cohort of 528 NSCLC subjects and 600 healthy controls. By restriction fragment length polymorphism (RFLP) method, we found that the distributions of the CTLA-4 and PD-1 gene polymorphisms were similar between NSCLC patients and healthy controls. However, for the PD-L1 8923 A/C polymorphism, frequencies of the AC genotype and C-allele were significantly higher in NSCLC patients than in healthy controls (odds ratio [OR] =1.55; 95% confidence interval [CI] 1.13-2.13; P=0.006; OR=1.52; 95% CI 1.14-2.04; P=0.004, respectively). Stratification analysis revealed that prevalence of the 8923C allele was significantly increased in NSCLC patients who smoke compared to those non-smoking patients (OR=1.51; 95% CI 1.00-2.28; P<0.05). Moreover, NSCLC patients carrying the C-allele had higher risk of regional lymph node metastasis than those carrying the A-allele (OR=5.65; 95% CI 2.45~13.03; P<0.001). These data suggest that PD-L1+8293A>C polymorphism may play a role in the development and progression of NSCLC.

Association analysis of PTPN22, CTLA4 and IFIH1 genes with type 1 diabetes in Colombian families

BACKGROUND

Protein tyrosine phosphatase, non-receptor type 22 (lymphoid) (PTPN22), cytotoxic T-lymphocyte-associated protein 4 (CTLA4), and interferon induced with helicase C domain 1 (IFIH1) are among the confirmed type 1 diabetes (T1D) susceptibility genes in several populations. The aim of this study was to evaluate the role of PTPN22, CTLA4, and IFIH1 gene variants in the development of T1D in a Colombian population.

METHODS

Associations of PTPN22, CTLA4, and IFIH1 variants with T1D were investigated in a sample of 197 nuclear families, including 205 affected children, in the Colombian population. Three to four single nucleotide polymorphisms (SNPs) were analyzed per gene: rs2476600, rs2476601, rs1217418, and rs2488457 for PTPN22; rs1990760, rs3747517, and rs10930046 for IFIH1; and rs231775, rs3087243, and rs231779 for CTLA4. A transmission disequilibrium test was performed for the global sample, in addition to stratified analysis considering autoimmunity, age at onset, and parent of origin. Haplotypes per gene were also analyzed.

RESULTS

There was no significant transmission distortion for CTLA4. Conversely, SNPs rs10930046 (IFIH1) and rs2476601 (PTPN222) exhibited significant transmission distortion of the C and T alleles, respectively, from parents to affected children (odds ratio [OR] 0.57 and 1.83, respectively). In addition, decreased transmission of the C allele for rs10930046 occurred preferentially from mothers. Stratification analysis revealed that this association was maintained in individuals who were positive for autoantibodies and in those with an age of diagnosis <5 years.

CONCLUSION

The results show that IFIH1 and PTPN22 are associated with T1D in Colombian families.

Thyroid functions and trace elements in pediatric patients with exogenous obesity

Obesity is a multifactorial disease developing following impairment of the energy balance. The endocrine system is known to be affected by the condition. Serum thyroid hormones and trace element levels have been shown to be affected in obese children. Changes in serum thyroid hormones may result from alterations occurring in serum trace element levels. The aim of this study was to evaluate whether or not changes in serum thyroid hormone levels in children with exogenous obesity are associated with changes in trace element levels. Eighty-five children diagnosed with exogenous obesity constituted the study group, and 24 age- and sex-matched healthy children made up the control group. Serum thyroid stimulating hormone (TSH), free thyroxine (fT4), free triiodothyronine (fT3), thyroglobulin (TG), selenium (Se), zinc (Zn), copper (Cu), and manganese (Mn) levels in the study group were measured before and at the third and sixth months of treatment, and once only in the control group. Pretreatment fT4 levels in the study group rose significantly by the sixth month (p = 0.006). Zn levels in the patient group were significantly low compared to the control group (p = 0.009). Mn and Se levels in the obese children before and at the third and sixth months of treatment were significantly higher than those of the control group (p = 0.001, p = 0.001). In conclusion, fT4, Zn, Cu, Mn, and Se levels are significantly affected in children diagnosed with exogenous obesity. The change in serum fT4 levels is not associated with changes in trace element concentrations.