1. Introduction
Multiple sclerosis (MS) is a chronic inflammatory autoimmune disease of the central nervous system (CNS) [
1]. The incidence and prevalence rates of this disease are increasing worldwide. According to the Atlas of MS, 3rd edition, prepared by the Multiple Sclerosis International Federation, approximately 2.8 million people worldwide have MS. Lithuania belongs to the region of high prevalence and morbidity of MS (prevalence per 100,000 people is 101-200) [
2]. MS is most commonly diagnosed in people between 20 and 40 years of age. Less commonly, it occurs in childhood (less than 1%) and after the age of 50 (about 2-10%) [
3]. Moreover, MS is 2 to 3 times more common in women than in men [
4]. MS is a multifactorial disease whose development is influenced by genetic and environmental factors [
5]. Several pathological processes contribute to the development of MS, including blood-brain barrier (BBB) damage, multifocal inflammatory responses, demyelination, oligodendrocyte death, reactivated gliosis, and axonal degeneration [
6].
According to recent studies, cellular senescence caused by telomere shortening may contribute to the development of MS [
5]. To maintain the integrity of the genome, telomeres protect chromosomes from end fusion and degradation by exonucleases. Telomeres are specialized structures located at the ends of eukaryotic chromosomes and are composed of tandem nucleotide repeats (TTAGGG) and proteins [
7]. When telomeric DNA regions are critically shortened, they can signal replicative senescence of somatic cells and chromosome instability [
8]. Telomerase is a ribonucleoprotein enzyme critical for the replication of telomeric sequences in chromosomal DNA. The enzyme complex includes several components, including the telomerase RNA component (TERC), telomerase reverse transcriptase (TERT), dyskerin, and other accessory proteins such as TEP1 [
8,
9].
TERC binds to the 3' end of chromosomes and provides a template sequence for reverse transcription catalyzed by TERT [
10]. According to recent studies, TERC inhibits apoptosis in immune cells, protects neurons from oxidative stress, and enhances cellular inflammatory responses [
11]. TERC has been shown to increase the expression and release of inflammatory cytokines by directly binding to the promoters of the
LIN37,
TPRG1L,
TYROBP, and
USP16 genes. These four genes encode proteins involved in the activation of the transcription factor nuclear factor κB (NF-κB) [
11,
12]. Inflammatory responses lead to progressive shortening of telomeres, which has been linked to the development of age-related diseases [
13]. It has been observed that naive CD4
+ T cells from patients with rheumatoid arthritis exhibit increased telomerase inhibition, resulting in shortened telomeres due to decreased expression of TERT and TERC. For this reason, T cell subset aging is accelerated and autoimmunity is activated [
14]. TERC levels have been shown to be increased in individuals with MS or type II diabetes. It should be noted that these two diseases are associated with inflammatory responses [
12].
The
TERC gene is located on the long arm of chromosome 3 at position 26.2 (3q26.2) [
15].
TERC is responsible for regulating telomere length [
16]. Studies in mice have shown that
TERC is involved in neural progenitor cell (NPC) proliferation. It has been observed that in mice in which the
TERC gene is knocked out, there is a statistically significant decrease in the proliferation of NPC. It has also been found that neurons cannot fully mature when the
TERC gene is knocked out in NPC [
17]. In addition, studies have shown that
TERC gene polymorphisms influence the development of Alzheimer's disease [
18]. Since a relationship between
TERC and MS has been established in the scientific literature, we decided to analyze the SNP rs12696304 and rs35073794 of the
TERC gene. Polymorphisms in the
TERC gene have been associated with changes in telomere length due to altered telomerase activity [
19,
20,
21]. The SNP rs12696304 C > G is located in the in the downstream region of the
TERC gene, i.e. 1.5 kb away from the transcription start nucleotide [
21]. The rs35073794 A > G SNP is also located in the downstream region of the
TERC gene [
20]. Thus, polymorphisms in the
TERC gene may promote cellular senescence by altering the stability of the telomerase complex or directly affecting the enzymatic activity of telomerase [
18].
TEP1 is responsible for RNA and protein binding and is involved in the regulation of telomere length [
22,
23].
TEP1 is thought to function as a structural protein by binding to
TERC and acting as a regulatory subunit to mediate the interaction of telomerase with other molecules [
24]. In addition,
TEP1 and dyskerin are responsible for stabilizing the structure of telomerase [
25]. In addition,
TEP1 directly interacts with the BLM protein of Bloom syndrome and regulates its helicase activity. Thus, it can be assumed that
TEP1 is involved in telomere lengthening [
26].
The
TEP1 gene is located on the long arm of chromosome 14 at position 11.2 (14q11.2) [
27]. According to NCBI, the
TEP1 gene consists of 55 exons [
28]. This gene is responsible for telomere elongation and prevents neuron development due to DNA damage. Ren et al. found that
TEP1 is associated with white matter microstructure abnormality in schizophrenia [
29]. Using whole-exome sequencing, Sebate and colleagues discovered that pathogenic mutations in the
TEP1 gene contribute to the neurodegenerative disease of Parkinson's disease [
30]. According to the available data, there have been no studies investigating the association between
TEP1 and MS. Based on previous studies in neurological diseases, it can be assumed that the
TEP1 gene is involved in MS. In this study, we aimed to determine the influence of the
TEP1 gene SNP rs1760904 and rs1713418 on the occurrence of MS.The SNP rs1760904 A > G is located in the exon region of the
TEP1 gene [
23,
26]. Rs1760904 is a nonsynonymous SNP and causes a proline-to-serine substitution (Ser1195Pro) that may affect
TEP1 structure and telomerase [
26]. Rs1713418 A > G SNP is located in the 3'UTR region of the
TEP1 gene [
26]. SNP in the 3'UTR alters the ability of miRNA to bind to the target gene, which affects gene regulation and increases the risk of MS [
31].
Therefore, the aim of this study was to determine the associations of TEP1 rs1760904, rs1713418, TERC rs12696304 and rs35073794 polymorphisms with the occurrence in MS patients.
2. Materials and Methods
The study was performed at the Department of Neurology, Lithuanian University of Health Sciences and in the Ophthalmology laboratory, Neuroscience Institute Lithuanian University of Health Sciences. Ethical approval for this study was obtained from the Kaunas Regional Biomedical Research Ethics Committee (No. BE-2-102, issued November 14, 2019). Each study participant signed the informed consent form. The subjects were divided into two groups:
1. The first group of study participants consisted of 200 MS patients (n=200) aged 21 to 69 years. This group consisted of 98 (49%) females and 102 (51%) males participants. The MS diagnosis was confirmed using the 2017 diagnostic criteria: by clinical symptoms/relapses, Magnetic Resonance Imaging (MRI) findings of the brain and/or spinal cord with typical demyelinating lesions (according to MAGNIMS criteria), and positive oligoclonal bands (OCBs) in cerebrospinal fluid (CSF) [
32,
33].
2. The second group of study participants consisted of 230 healthy volunteers (n=230) aged 19 to 69 years. This group was composed of 133 (57.8%) females and 97 (42.2%) males. The control group consisted of individuals in good general health.
Patients were excluded if they had other systemic illnesses (diabetes mellitus, oncological diseases, systemic tissue disorders, chronic infectious diseases, autoimmune diseases, conditions after organ or tissue transplantation), obscuration of the eye optic system, or because of poor fundus photography quality.
The demographic factors of the patients in the study MS and the control group - age and gender - were evaluated in the study. Subjects were divided into < 44 years and ≥44 years old.
2.1. DNA Extraction and Genotyping
Genomic DNA was extracted from peripheral blood leukocytes by a salting-out method. Genotyping of TEP1 rs1760904, rs1713418 and TERC rs12696304, rs35073794 was performed by real-time polymerase chain reaction (RT-PCR). To determine SNPs, we used TaqMan® genotyping assays (Applied Biosystems, New York, NY, USA; Thermo Fisher Scientific, Inc., Waltham, MA, USA) according to the manufacturer's recommendations. Assay IDs: C___1772362_20 (TEP1 rs1760904), C___8921332_10 (TEP1 rs1713418), C____407063_10 (TERC rs12696304), and C__58097851_10 (TERC rs35073794).
2.2. Statistical Analysis
The statistical analysis of the scientific work was carried out with "IBM SPSS Statistics 29.0.". In this study, Kolmogorov-Smirnov and Shapiro-Wilk tests were used to evaluate the hypothesis about the normal distribution of the measured trait values. Because the subjects' characteristics did not meet the requirements of a normal distribution, the following descriptive statistics were used: Median and Interquartile Range (IQR).
The χ²-test and Fisher's exact test were used to compare the homogeneity of the genotypes and allele distributions of the TEP1 rs1760904, rs1713418, TERC rs12696304, and rs35073794 gene polymorphisms. In addition, binary logistic regression was performed to evaluate the influence of genotypes and alleles on the occurrence of MS. Considering inheritance models and genotype combinations, the odds ratio (OR) was determined with a 95% confidence interval (CI). According to the Akaike Information Criterion (AIC), the model with the lowest value is the most appropriate inheritance model. As part of the analysis, the program "SNPStats" was also used to analyze the haplotypes. An evaluation of the linkage disequilibrium between the studied gene polymorphisms was performed. The deviation between the expected haplotype frequency and the observed frequency (D') was calculated and the square of the correlation coefficient of the haplotype frequency (r2) was evaluated.
3. Results
The study involved 430 subjects who were divided into two groups: a control group (n=230) and a group of subjects with MS (n=200). After the formation of the study groups, genotyping of
TEP1 rs1760904, rs1713418,
TERC rs12696304 and rs35073794 polymorphisms was performed. The group of patients with MS consisted of 200 individuals: 98 females (49%) and 102 males (51%). The average age of the MS patients was 38 years. The control group consisted of 230 subjects: 133 females (57.8%) and 97 males (42.2%). The median age of the control group was 43.5 years. Sex and age did not differ between the groups. The demographic data of the subjects are shown in
Table 1.
Associations of TEP1 (rs1760904, rs1713418) and TERC (rs12696304, rs35073794) with Multiple Sclerosis
Analysis of the genotype and allele distribution of
TEP1 rs1760904, rs1713418 and
TERC rs12696304, rs35073794 revealed that the
TERC rs12696304 G allele was less frequent in the MS group than in the control group (20.5% vs. 26.5%, p=0.038). In addition, the
TERC rs35073794 GG genotype was found to be more frequent in the MS group than in the control group (54.0% vs. 32.6%, p < 0.001). AG Genotype and A allele of the same polymorphism are less frequent in the MS group than in the control group (45.5% vs. 67.4%, p < 0.001; 23.25 vs. 33.7, p < 0.001) (
Table 2).
No statistically significant differences were found in the distribution of genotypes and alleles of
TEP1 gene rs1760904 and rs1713418 between groups MS and control group (
Table 2).
After performing binary logistic regression, we found that each G allele of the
TERC gene polymorphism rs12696304 was associated with a 1.4-fold decrease in the probability of occurrence of MS (OR: 0.703, (95% CI: 0.506-0.976), p=0.035).
TERC rs35073794 is associated with an approximately 2.4-fold reduced odds of MS occurrence in the codominant, dominant, overdominant, and additive models (OR: 0.408, (95% CI: 0.275 - 0.603), p < 0.001; OR: 0.412 (95% CI: 0.279 - 0.610), p < 0.001; OR: 0.404 (95% CI: 0.273 - 0.598), p < 0.001; OR: 0.427 (95% CI: 0.289 - 0.629), p < 0.001, respectively) (
Table 3). However, analysis of
TEP1 rs1760904 and rs1713418 revealed no statistically significant differences (
Table 3).
Association of Single Nucleotide Polymorphisms of TEP1 (rs1760904, rs1713418) and TERC (rs12696304, rs35073794) Genes with Multiple Sclerosis Regarding Gender of the Subjects
Analysis of SNP data in males and females revealed that the
TERC rs12696304 genotype CC and the C allele were more prevalent in the group of males with MS than in the control group of males (68.6% vs. 52.6%, p=0.020; 83.33% vs. 72.16%, p=0.007, respectively). In contrast, the
TERC rs12696304 GG genotype is less frequent in the group of men with MS than in the control group of men (2.0% vs. 8.2%, p=0.043). The TERC rs35073794 GG genotype is more frequent in the group of men with MS than in the control group of men (59.8% vs. 25.8%, p < 0.001). In addition, the AG genotype and the A allele of the same polymorphism are less frequent in the group of men with MS than in the control group of men (39.2% vs. 74.2%, p < 0.001; 20.59% vs. 37.11%, p < 0.001, respectively). When the distribution of
TEP1 rs1760904 and rs1713418 genotypes and alleles was analysed between men with MS and healthy men, no differences were found (
Table 4).
No differences were found when comparing the distribution of genotypes and alleles of
TEP1 rs1760904, rs1713418 and
TERC rs12696304, rs35073794 between women with MS and the female control group (p>0,05) (
Table 4).
Using binary logistic regression, we examined the effects of TEP1 rs1760904, rs1713418 and TERC rs12696304, rs35073794 on the occurrence of MS in men and women separately.
When the male group was analyzed, TERC rs12696304 was found to be associated with a decreased odds of MS occurrence in males in the codominant, dominant, and additive models (5.5-fold (OR: 0.182, (95% CI: 0.037-0.894), p=0.036), 2-fold (OR =0.507, (95% CI: 0.284-0.903), p=0.021) and 1.9-fold (OR: 0.515, (95% CI: 0.314-0.845), p=0.009), respectively). TERC rs35073794 is associated with approximately 4.4-fold decreased odds of MS occurring in males in the codominant, dominant, and overdominant models (OR: 0.228, (95% CI: 0.124 - 0.417), p < 0.001; OR: 0.233 (95% CI: 0.128 - 0.427), p < 0.001; OR: 0.224 (95% CI: 0.122 - 0.410), p < 0.001, respectively). In addition, we found that TERC rs35073794 each A allele was associated with a 3.9-fold decreased odds of MS occurrence in males (OR: 0.256, (95% CI: 0.141 - 0.462), p < 0.001). After performing binary logistic regression of TEP1 rs1760904, rs1713418, we found no statistically significant differences between MS men and control men.
When binary logistic regression analysis of
TEP1 rs1760904, rs1713418 and
TERC rs12696304, rs35073794 gene polymorphisms was performed, no statistically significant differences were found between women with MS and healthy women (p>0,05). Data show in
Table 5.
3.2.2. Association of Single Nucleotide Polymorphisms of TEP1 (rs1760904, rs1713418) and TERC (rs12696304, rs35073794) Genes with Multiple Sclerosis Regarding Age of the Subjects
In this study, we investigated the influence of TEP1 rs1760904, rs1713418 and TERC rs12696304, rs35073794 gene polymorphisms on the occurrence of MS according to age groups. Subjects were divided into < 44 years and ≥44 years old.
Genotype and allele distribution analysis revealed that the
TERC rs35073794 GG genotype was more prevalent in MS patients younger than 44 years than in the control group (55.6% vs. 27.0%, p < 0.001). In addition, the same polymorphism A allele was found to be less frequent in MS patients younger than 44 years compared to the control group (22.2% vs. 36.5%, p < 0.001). When analysing the genotype and allele distribution of
TEP1 rs1760904, rs1713418 and
TERC rs12696304, no statistically significant differences were found between MS patients younger than 44 years and the control group (p>0.05). When comparing the distribution of genotypes and alleles of
TEP1 rs1760904, rs1713418 and
TERC rs12696304, rs35073794, we found no statistically significant differences between subjects older than 44 years with MS and those in the control group (
Table 6).
MS - multiple sclerosis; p-value - significance level (statistically significant when p < 0.05), statistically significant results are bold.
Based on binary logistic regression of gene polymorphisms
TEP1 rs1760904, rs1713418, and
TERC rs12696304, individuals younger than 44 years with MS and the control group had no statistically significant differences. However,
TERC rs35073794 is associated with an approximately 3.4-fold decrease in the odds of individuals younger than 44 years with MS under the dominant, overdominant, and additive models (OR: 0.295, (95% CI: 0.173 - 0.503), p < 0.001; OR: 0.295 (95% CI: 0.173 - 0.503), p < 0.001; OR: 0.295 (95% CI: 0.173 - 0.503), p < 0.001, respectively) (
Table 7).
Binary logistic regression analysis in individuals over 44 years of age revealed that the
TEP1 rs1713418 GG genotype was associated with a 2.2-fold increased odds of MS occurrence in individuals over 44 years of age compared with the AG and AA genotypes (OR: 2.191, (95% CI: 1.020-4.708), p=0.044). However, analysis of polymorphisms of
TEP1 rs1760904 and TERC rs12696304, rs35073794 genes between the group of individuals with MS aged ≥44 years and the control group did not reveal statistically significant differences (
Table 7).
3.3. Haplotype Analysis of TEP1 (rs1760904, rs1713418) and TERC (rs12696304, rs35073794)
TEP1 rs1760904, rs1713418 SNP Genotype and Haplotype Analysis in MS Patients and Healthy Subjects
The deviation between the expected haplotype and the observed frequency (D') was equal to 0.471. It was also determined that the square of the correlation coefficient of haplotype frequency (r2) was 0.146 (
Table 8).
The
TEP1 rs1760904-A - rs1713418-A haplotype was the most common in the study group and was therefore selected as a reference. Haplotype analysis revealed that the rs1760904-G - rs1713418-A haplotype was associated with a 1.7-fold increased odds of occurrence of MS (OR: 1.74, (95% CI: 1.18-2.56), p=0.006). In addition, the rs1760904-A - rs1713418-G haplotype is associated with a 1.9-fold increased odds of the MS occurrence (OR: 1.92, (95% CI: 1.14-3.24), p=0.014). The data are presented in
Table 9.
According to our calculations, the deviation between the expected haplotype and observed frequency (D') was equal to 0.019. Moreover, the square of the haplotype frequency correlation coefficient (r2) was found to be <0.001 (
Table 10).
The
TERC rs12696304-C - rs35073794-G haplotype was the most common in the study group and was therefore selected as a reference. Haplotype analysis revealed that the rs12696304-C - rs35073794-A haplotype was associated with a 2-fold reduction in the odds of MS occurrence (OR: 0.51, (95% CI: 0.32-0.84), p=0.008). In addition, the rs12696304-G - rs35073794-A haplotype is associated with a 5.3-fold reduction in the odds of MS occurrence (OR: 0.19, (95% CI: 0.08-0.49), p < 0.001) (
Table 11).
4. Discussion
In our study we analyzed the polymorphisms of the
TEP1 gene rs1760904, rs1713418, the
TERC gene rs12696304, and rs35073794 in 200 MS patients and 230 healthy individuals, because the SNPs we selected have not been studied in scientific research on the pathogenesis and development of MS. It should be noted that aging and genetic variants affecting telomere length, telomerase activation, and telomeric protein configuration can cause functional changes in cells [
26,
34].
Sipos and co-authors found that TEP1 expression is increased in ulcerative colitis during mild inflammation [
35]. Gu and coauthors found that
TEP1 rs1713418 AG +AA genotypes were associated with a 1.3-fold increased odds of prostate cancer in individuals younger than ≤69 years compared with the AA genotype (OR: 1.32, (95% CI: 1.02-1.70), p=0.034). However, the AG +GG genotype of the same polymorphism is associated with a 1.4-fold lower odds of prostate cancer in individuals older than > 69 years compared to the AA genotype (OR: 0.71, (95% CI: 0.55-0.92), p=0.010) [
26]. Sun et al. found that
TEP1 rs1713418 was associated with a 1.3-fold increased odds of ovarian cancer occurrence (OR: 1.33, (95% CI: 1.08-1.65), p=0.009) [
36]. It should be noted that excessive or persistent inflammation contributes to carcinogenesis and tumor progression through the activation of inflammatory molecules and signals [
37]. Our study found that the
TEP1 rs1713418 GG genotype was associated with a 2.2-fold increased odds of MS occurrence in individuals older than 44 years compared with the AG and AA genotypes (OR: 2.191, (95% CI: 1.020-4.708), p=0.044).
Chan and co-authors performed a haplotype analysis and found that the
TEP1 haplotype, consisting of the SNP allele variants rs1713418, rs2104978, rs17211355, rs2297615, rs2228041, rs2228026, and rs1713440, was associated with a 2.2-fold increased odds of bladder cancer occurrence (OR: 2.23, (95% CI: 1.13-4.60), p=0.022) [
38]. This study revealed that chronic inflammation may play a role in the development of malignancies, including bladder cancer [
37]. Our haplotype analysis revealed that the rs1760904-G - rs1713418-A haplotype was statistically significantly associated with a 1.7-fold increased likelihood of developing MS (OR: 1.740, (95% CI: 1.180-2.560), p=0.006). The rs1760904-A - rs1713418-G haplotype is statistically significantly associated with a 1.9-fold increased probability of the occurrence of MS (OR: 1.920, (95% CI: 1.140-3.240), p=0.014).
Liu et al. found that TERC expression was increased more in MS patients than in healthy individuals (p < 0.01) [
12]. Scarabino and co-authors found that
TERC rs12696304 GG genotype correlated with the occurrence of Alzheimer's disease [
18]. In addition, the results of a study conducted by Sun and coauthors suggested that the
TERC gene rs12696304 G allele and GG genotype were statistically significantly associated with a 1.6-fold increased odds of developing chronic kidney disease (OR: 1.555, (95% CI: 1.215-1.990), p=0.001; OR: 1.634, (95% CI: 1.201-2.234), p=0.002, respectively). In addition, the researchers found that the G allele of the same polymorphism was associated with a 1.8-fold increased odds of developing chronic kidney disease in the female group (OR:1.816, (95% CI: 1.248-2.641), p=0.002), and the GG genotype was associated with a 2-fold increased odds of developing chronic kidney disease in the female group (OR: 1.959, (95% CI: 1.233-3.114), p= 0.006). The authors also found that the rs12696304 G allele could contribute to a host autoimmune response targeting glomerular tissues by activating the NF-κB pathway via TERC [
14]. It is known that secretory renal dysfunction (decreased synthesis of vitamin D, erythropoietin, and Klotho protein) may contribute to brain dysfunction in MS patients [
39]. According to the results of Al Khaldu and co-authors, the genotype of
TERC gene rs12696304 GG is associated with a 1.6-fold increased probability of developing type 2 diabetes (OR: 1.6, (95% CI: 1.5-1.9), p=0.005) [
40]. It should be noted that diabetes, like MS, is associated with increased oxidative stress and inflammatory responses, which may accelerate telomere shortening and associated cellular senescence [
41]. After performing binary logistic regression, we found that the
TERC gene rs12696304 G allele was associated with a 1.4-fold decrease in the likelihood of occurrence of MS (OR: 0.703, (95% CI: 0.506-0.976), p=0.035).
TERC rs12696304 is associated with a decreased probability of occurrence of MS in males in the codominant, dominant, and additive models (5.5-fold (OR: 0.182, (95% CI: 0.037-0.894), p=0.036), 2-fold (OR =0.507, (95% CI: 0.284-0.903), p=0.021) and 1.9-fold (OR: 0.515, (95% CI: 0.314-0.845), p=0.009).
Wu and co-authors found that
TERC rs35073794 is associated with a 2.4-fold increased odds of renal cell carcinoma (RCC) occurrence in an allele model (A/G) (OR =2.39, 95% CI = 0.99-5.80, p = 0.047). The authors also found that rs35073794 AG genotype is associated with a 2.6-fold increased odds of RCC risk with adjustment for gender, age and BMI (OR =2.61, 95% CI = 1.01-6.76, p = 0.045) [
20]. We found that
TERC rs35073794 is associated with about 2.4-fold decreased odds of MS development under codominant, dominant, overdominant, and additive model (OR: 0.408, (95% CI: 0.275 - 0.603), p<0.001; OR: 0.412 (95% CI: 0.279 - 0.610), p<0.001; OR: 0.404 (95% CI: 0.273 - 0.598), p<0.001; OR: 0.427 (95% CI: 0.289 - 0.629), p<0,001, respectively).
TERC rs35073794 is associated with about 4.4-fold decreased odds of MS occurrence in men under codominant, dominant, and overdominant model (OR: 0.228, (95% CI: 0.124 - 0.417), p<0.001; OR: 0.233 (95% CI: 0.128 - 0.427), p<0.001; OR: 0.224 (95% CI: 0.122 - 0.410), p<0.001, respectively). Furthermore,
TERC rs35073794 each A allele is associated with a 3.9-fold decreased odds of MS occurrence (OR: 0.256, (95% CI: 0.141 - 0.462), p<0.001).
TERC rs35073794 is associated with about 3.4-fold decreased odds of subjects younger than 44 years of age with MS under dominant, overdominant and additive model (OR: 0.295, (95% CI: 0.173 - 0.503), p<0.001; OR: 0.295 (95% CI: 0.173 - 0.503), p<0.001; OR: 0.295 (95% CI: 0.173 - 0.503), p<0.001, respectively).
Based on haplotype analysis, Maubaret and colleagues found that the
TERC rs12696304-G-rs10936601-T-rs16847897-C haplotype was statistically significantly associated with a 1.35-fold reduction in the risk of developing type 2 diabetes (OR: 0.74, (95% CI: 0.61-0.91), p=0.004) [
42]. According to our haplotype analysis, the rs12696304-C-rs35073794-A haplotype is associated with a 2-fold reduction in the likelihood of developing MS (OR: 0.51, (95% CI: 0.32-0.84), p=0.008). In addition, we discovered that the rs12696304-G-rs35073794-A haplotype was associated with a 5.3-fold reduction in the probability of MS occurrence (OR: 0.19, (95% CI: 0.08-0.49), p < 0.001).
In our study, we have several limitations. Sample representativeness: the study rely on a sample of participants, which may not fully represent the diversity of the target population. For more accurate results, the sample size should be increased. The study exhibits strengths in its rigorous methodology, characterized by clear objectives, appropriate sample sizes, and robust data collection. These elements significantly enhance the reliability and validity of our study's findings. Additionally, the study adheres to standardized protocols and procedures, enabling the potential for replication and facilitating comparability with other studies.
There is evidence that telomere-related genes play a critical role in carcinogenesis. However, it is still unclear whether alterations in telomere-related genes may contribute to the progression and occurrence of MS [
26]. Therefore, this study warrants further research to explain the pathogenesis of MS and the impact of telomere-related gene alterations on the development of MS.
Table 1.
Demographic characteristics of the study groups.
Table 1.
Demographic characteristics of the study groups.
Characteristics |
Group |
p-value |
MS group |
Control group |
Gender |
Males, N (%) |
102 (51) |
97 (42.2) |
0.067 |
Females, N (%) |
98 (49) |
133 (57.8) |
Age, Median (IQR) |
38 (15) |
43.5 (28) |
0.117 |
Table 2.
Distribution of TEP1 rs1760904, rs1713418, TERC rs12696304, rs35073794 genotypes and alleles within patients with MS and control group subjects.
Table 2.
Distribution of TEP1 rs1760904, rs1713418, TERC rs12696304, rs35073794 genotypes and alleles within patients with MS and control group subjects.
Gene, SNP |
Genotype and allele |
Distribution |
MS group, N (%) |
Control group, N (%) |
p-value |
TEP1 rs1760904 |
Genotype AA AG GG |
44 (22.00) 96 (48.00) 60 (30.00) |
56 (24.30) 122 (53.00) 52 (22.60) |
0.219 |
Allele A G |
184 (46.00) 216 (54.00) |
234 (50.87) 226 (49.13) |
0.154 |
TEP1 rs1713418 |
Genotype AA AG GG |
72 (36.00) 86 (43.00) 42 (21.00) |
81 (35.20) 114 (49.60) 35 (15.20) |
0.222 |
Allele A G |
230 (57.50) 170 (42.50) |
276 (60.00) 184 (40.00) |
0.457 |
TERC rs12696304 |
Genotype CC CG GG |
124 (62.00) 70 (35.00) 6 (3.00) |
123 (53.50) 92 (40.00) 15 (6.50) |
0.092 |
Allele C G |
318 (79.50) 82 (20.50) |
338 (73.48) 122 (26.52) |
0.038 |
TERC rs35073794 |
Genotype GG AG AA |
108 (54.00)1 91 (45.50)2 1 (0.50) |
75 (32.60)1 155 (67.40)2 0 (0.00) |
<0.001 |
Allele G A |
307 (76.75) 93 (23.25) |
305 (66.30) 155 (33.70) |
<0.001 |
Table 3.
Binary logistic regression analysis of TEP1 rs1760904, rs1713418, TERC rs12696304, rs35073794 within patients with MS and control group subjects.
Table 3.
Binary logistic regression analysis of TEP1 rs1760904, rs1713418, TERC rs12696304, rs35073794 within patients with MS and control group subjects.
Model |
Genotype/Allele |
OR (95% CI) |
p-value |
AIC |
TEP1 rs1760904 |
Codominant |
AG vs. AA GG vs. AA |
1.001 (0.622 - 1.613) 1.469 (0.854 - 2.525) |
0.995 0.165 |
594.983 |
Dominant |
AG + GG vs. AA |
1.141 (0.727 - 1.790) |
0.566 |
595.681 |
Recessive |
GG vs. AG + AA |
1.467 (0.952 - 2.260) |
0.082 |
592.983 |
Overdominant |
AG vs. AA+GG |
0.817 (0.559 - 1.194) |
0.297 |
594.923 |
Additive |
G |
1.220 (0.930 - 1.600) |
0.152 |
593.947 |
TEP1 rs1713418 |
Codominant |
AG vs. AA GG vs. AA |
0.849 (0.556 - 1.296) 1.350 (0.779 - 2.339) |
0.447 0.284 |
595.007 |
Dominant |
AG + GG vs. AA |
0.966 (0.651 - 1.436) |
0.866 |
595.983 |
Recessive |
GG vs. AG+AA |
1.481 (0.903 - 2.430) |
0.120 |
593.584 |
Overdominant |
AG vs. AA+GG |
0.768 (0.524 - 1.124) |
0.174 |
594.156 |
Additive |
G |
1.104 (0.845 - 1.443) |
0.466 |
595.481 |
TERC rs12696304 |
Codominant |
CG vs. CC GG vs. CC |
0.755 (0.507 - 1.124) 0.397 (0.149 - 1.056) |
0.166 0.064 |
593.121 |
Dominant |
CG+GG vs. CC |
0.705 (0.479 - 1.036) |
0.075 |
592.826 |
Recessive |
GG vs. CG+CC |
0.443 (0.169 - 1.165) |
0.099 |
593.043 |
Overdominant |
CG vs. CC+GG |
0.808 (0.546 - 1.196) |
0.286 |
594.871 |
Additive |
G |
0.703 (0.506 - 0.976) |
0.035 |
591.502 |
TERC rs35073794 |
Codominant |
AG vs. GG AA vs. GG |
0.408 (0.275 - 0.603) - |
<0.001 - |
575.893 |
Dominant |
AG + AA vs. GG |
0.412 (0.279 - 0.610) |
<0.001 |
575.875 |
Recessive |
AA vs. AG+GG |
- |
- |
- |
Overdominant |
AG vs. AA+GG |
0.404 (0.273 - 0.598) |
<0.001 |
574.944 |
Additive |
A |
0.427 (0.289 - 0.629 |
<0.001 |
577.123 |
Table 4.
Distribution of TEP1 rs1760904, rs1713418, TERC rs12696304, rs35073794 genotypes and alleles within patients with MS and control group subjects regarding gender.
Table 4.
Distribution of TEP1 rs1760904, rs1713418, TERC rs12696304, rs35073794 genotypes and alleles within patients with MS and control group subjects regarding gender.
Genotype and Allele. |
Males |
p-value |
Females |
p-value |
MS group, N (%) |
Control group, N (%) |
MS group, N (%) |
Control group, N (%) |
TEP1 rs1760904 |
Genotype AA AG GG |
25 (24.50) 50 (49.00) 27 (26.50) |
28 (28.90) 51 (52.60) 18 (18.60) |
0.395 |
19 (19.40) 46 (46.90) 33 (33.70) |
28 (21.10) 71 (53.40) 34 (25.60) |
0.403 |
Allele A G |
100 (49.02) 104 (50.98) |
107 (55.15) 87 (44.85) |
0.221 |
84 (42.86) 112 (57.14) |
127 (47.74) 139 (52.26) |
0.297 |
TEP1 rs1713418 |
Genotype AA AG GG |
40 (39.20) 46 (45.10) 16 (15.70) |
32 (33.00) 52 (53.60) 13 (13.40) |
0.486 |
32 (32.70) 40 (40.80) 26 (26.50) |
49 (36.80) 62 (46.60) 22 (16.50) |
0.181 |
Allele A G |
126 (61.76) 78 (38.24) |
116 (59.79) 78 (40.21) |
0.687 |
104 (53.06) 92 (46.94) |
160 (60.15) 106 (39.85) |
0.128 |
TERC rs12696304 |
Genotype CC CG GG |
70 (68.60)1 30 (29.40) 2 (2.00)2
|
51 (52.60)1 38 (39.20) 8 (8.20)2
|
0.025 |
54 (55.10) 40 (40.80) 4 (4.10) |
72 (54.10) 54 (40.60) 7 (5.30) |
0.916 |
Allele C G |
170 (83.33) 34 (16.67) |
140 (72.16) 54 (27.84) |
0.007 |
148 (75.51) 48 (24.49) |
198 (74.44) 68 (25.56) |
0.792 |
TERC rs35073794 |
Genotype GG AG AA |
61 (59.80)3 40 (39.20)4 1 (1.00) |
25 (25.80)3 72 (74.20)4 0 (0.00) |
<0.001 |
47 (48.00) 51 (52.00)
|
50 (37.60) 83 (62.40)
|
0.115 |
Allele G A |
162 (79.41) 42 (20.59) |
122 (62.89) 72 (37.11) |
<0.001 |
145 (73.98) 51 (26.02) |
183 (68.80) 83 (31.20) |
0.225 |
Table 5.
Binary logistic regression analysis of TEP1 rs1760904, rs1713418, TERC rs12696304, rs35073794 within patients with MS and control group subjects regarding gender.
Table 5.
Binary logistic regression analysis of TEP1 rs1760904, rs1713418, TERC rs12696304, rs35073794 within patients with MS and control group subjects regarding gender.
Model |
Genotype/Allele |
OR (95% CI) |
p-value |
AIC |
Males |
TEP1 rs1760904 |
Codominant |
AG vs. AA GG vs. AA |
1.098 (0.564 - 2.136) 1.680 (0.752 - 3.754) |
0.783 0.206 |
277.881 |
Dominant |
AG + GG vs. AA |
1.250 (0.666 - 2.346) |
0.488 |
277.264 |
Recessive |
GG vs. AG + AA |
1.580 (0.805 - 3.103) |
0.184 |
275.956 |
Overdominant |
AG vs. AA+GG |
0.867 (0.497 - 1.513) |
0.616 |
277.495 |
Additive |
G |
1.286 (0.862 - 1.918) |
0.218 |
276.218 |
TEP1 rs1713418 |
Codominant |
AG vs. AA GG vs. AA |
0.708 (0.384 - 1.304) 0.985 (0.414 - 2.343) |
0.267 0.972 |
278.303 |
Dominant |
AG + GG vs. AA |
0.763 (0.427 - 1.364) |
0.361 |
276.911 |
Recessive |
GG vs. AG+AA |
1.202 (0.545 - 2.652) |
0.648 |
277.538 |
Overdominant |
AG vs. AA+GG |
0.711 (0.407 - 1.242) |
0.231 |
276.305 |
Additive |
G |
0.918 (0.609 - 1.383) |
0.682 |
277.579 |
TERC rs12696304 |
Codominant |
CG vs. CC GG vs. CC |
0.575 (0.316 - 1.047) 0.182 (0.037 - 0.894) |
0.071 0.036 |
272.078 |
Dominant |
CG+GG vs. CC |
0.507 (0.284 - 0.903) |
0.021 |
272.350 |
Recessive |
GG vs. CG+CC |
0.223 (0.046 - 1.075) |
0.062 |
273.377 |
Overdominant |
CG vs. CC+GG |
0.647 (0.359 - 1.167) |
0.148 |
275.637 |
Additive |
G |
0.515 (0.314 - 0.845) |
0.009 |
270.497 |
TERC rs35073794 |
Codominant |
AG vs. GG AA vs. GG |
0.228 (0.124 - 0.417) - |
<0.001 - |
253.671 |
Dominant |
AG + AA vs. GG |
0.233 (0.128 - 0.427) |
<0.001 |
253.714 |
Recessive |
AA vs. AG+GG |
- |
- |
- |
Overdominant |
AG vs. AA+GG |
0.224 (0.122 - 0.410) |
<0.001 |
252.353 |
Additive |
A |
0.256 (0.141 - 0.462) |
<0.001 |
255.882 |
Females |
TEP1 rs1760904 |
Codominant |
AG vs. AA GG vs. AA |
0.955 (0.479 - 1.905) 1.430 (0.673 - 3.041) |
0.896 0.352 |
317.102 |
Dominant |
AG + GG vs. AA |
1.109 (0.578 - 2.127) |
0.756 |
316.814 |
Recessive |
GG vs. AG + AA |
1.478 (0.834 - 2.619) |
0.181 |
315.119 |
Overdominant |
AG vs. AA+GG |
0.772 (0.458 - 1.303) |
0.333 |
315.972 |
Additive |
G |
1.224 (0.840 - 1.784) |
0.293 |
315.798 |
TEP1 rs1713418 |
Codominant |
AG vs. AA GG vs. AA |
0.988 (0.544 - 1.795) 1.810 (0.879 - 3.724) |
0.968 0.107 |
315.523 |
Dominant |
AG + GG vs. AA |
1.203 (0.694 - 2.085) |
0.510 |
316.474 |
Recessive |
GG vs. AG+AA |
1.822 (0.960 - 3.457) |
0.066 |
313.525 |
Overdominant |
AG vs. AA+GG |
0.790 (0.466 - 1.339) |
0.381 |
316.139 |
Additive |
G |
1.302 (0.911 - 1.862) |
0.148 |
314.801 |
TERC rs12696304 |
Codominant |
CG vs. CC GG vs. CC |
0.988 (0.576 - 1.695) 0.762 (0.212 - 2.735) |
0.964 0.677 |
318.732 |
Dominant |
CG+GG vs. CC |
0.962 (0.569 - 1.624) |
0.884 |
316.889 |
Recessive |
GG vs. CG+CC |
0.766 (0.218 - 2.693) |
0.678 |
316.734 |
Overdominant |
CG vs. CC+GG |
1.009 (0.593 - 1.716) |
0.974 |
316.909 |
Additive |
G |
0.940 (0.602 - 1.466) |
0.784 |
316.835 |
TERC rs35073794 |
Codominant |
AG vs. GG AA vs. GG |
- - |
- - |
- |
Dominant |
AG + AA vs. GG |
0.654 (0.385 - 1.110) |
0.115 |
314.425 |
Recessive |
AA vs. AG+GG |
- |
- |
- |
Overdominant |
AG vs. AA+GG |
0.654 (0.385 - 1.110) |
0.115 |
314.425 |
Additive |
A |
0.654 (0.385 - 1.110) |
0.115 |
314.425 |
Table 6.
Distribution of TEP1 rs1760904, rs1713418, TERC rs12696304, rs35073794 genotypes and alleles within patients with MS and control group subjects regarding age.
Table 6.
Distribution of TEP1 rs1760904, rs1713418, TERC rs12696304, rs35073794 genotypes and alleles within patients with MS and control group subjects regarding age.
Genotype and Allele |
<44 |
p-value |
44 |
p-value |
MS group, N (%) |
Control group, N (%) |
MS group, N (%) |
Control group, N (%) |
TEP1 rs1760904 |
Genotype AA AG GG |
28 (20.70) 64 (47.40) 43 (31.90) |
27 (23.50) 59 (51.30) 29 (25.20) |
0.509 |
16 (24.60) 32 (49.20) 17 (26.20) |
29 (25.20) 63 (54.80) 23 (20.00) |
0.620 |
Allele A G |
120 (44.44) 150 (55.56) |
113 (49.13) 117 (50.87) |
0.295 |
64 (49.23) 66 (50.77) |
121 (52.61) 109 (47.39) |
0.538 |
TEP1 rs1713418 |
Genotype AA AG GG |
54 (40.00) 56 (41.50) 25 (18.50) |
41 (35.70) 55 (47.80) 19 (16.50) |
0.603 |
18 (27.70) 30 (46.20) 17 (26.20) |
40 (34.80) 59 (51.30) 16 (13.90) |
0.119 |
Allele A G |
164 (60.74) 106 (39.26) |
137 (59.57) 93 (40.43) |
0.789 |
66 (50.77) 64 (49.23) |
139 (60.43) 91 (39.57) |
0.075 |
TERC rs12696304 |
Genotype CC CG GG |
87 (64.40) 45 (33.30) 3 (2.20) |
63 (54.80) 47 (40.90) 5 (4.30) |
0.246 |
37 (56.90) 25 (38.50) 3 (4.60) |
60 (52.20) 45 (39.10) 10 (8.70) |
0.567 |
Allele C G |
219 (81.11) 51 (18.89) |
173 (75.22) 57 (24.78) |
0.110 |
99 (76.15) 31 (23.85) |
165 (71.74) 65 (28.26) |
0.363 |
TERC rs35073794 |
Genotype AA AG GG |
60 (44.40) 75 (55.60) |
84 (73.00) 31 (27.00) |
<0.001 |
1 (1.50) 31 (47.70) 33 (50.80) |
0 (0.00) 71 (61.70) 44 (38.30) |
0.094 |
Allele A G |
60 (22.22) 210 (77.78) |
84 (36.52) 146 (63.48) |
<0.001 |
33 (25.39) 97 (74.61) |
71 (30.87) 159 (69.13) |
0.270 |
Table 7.
Binary logistic regression analysis of TEP1 rs1760904, rs1713418, TERC rs12696304, rs35073794 within patients with MS and control group subjects regarding age.
Table 7.
Binary logistic regression analysis of TEP1 rs1760904, rs1713418, TERC rs12696304, rs35073794 within patients with MS and control group subjects regarding age.
Model |
Genotype/Allele |
OR (95% CI) |
p-Value |
AIC |
<44 |
TEP1 rs1760904 |
Codominant |
AG vs. AA GG vs. AA |
1.046 (0.554 - 1.976) 1.430 (0.704 - 2.902) |
0.890 0.322 |
347.612 |
Dominant |
AG + GG vs. AA |
1.172 (0.644 - 2.135) |
0.603 |
346.701 |
Recessive |
GG vs. AG + AA |
1.386 (0.796 - 2.415) |
0.249 |
345.632 |
Overdominant |
AG vs. AA+GG |
0.856 (0.520 - 1.408) |
0.539 |
346.594 |
Additive |
G |
1.205 (0.848 - 1.713) |
0.299 |
345.887 |
TEP1 rs1713418 |
Codominant |
AG vs. AA GG vs. AA |
0.773 (0.446 - 1.341) 0.999 (0.486 - 2.056) |
0.360 0.998 |
347.959 |
Dominant |
AG + GG vs. AA |
0.831 (0.497 - 1.390) |
0.480 |
346.473 |
Recessive |
GG vs. AG+AA |
1.148 (0.596 - 2.214) |
0.680 |
346.801 |
Overdominant |
AG vs. AA+GG |
0.773 (0.469 - 1.276) |
0.315 |
345.959 |
Additive |
G |
0.955 (0.675 - 1.351) |
0.796 |
346.905 |
TERC rs12696304 |
Codominant |
CG vs. CC GG vs. CC |
0.693 (0.411 - 1.168) 0.434 (0.100 - 1.885) |
0.169 0.266 |
346.168 |
Dominant |
CG+GG vs. CC |
0.668 (0.402 - 1.112) |
0.121 |
344.557 |
Recessive |
GG vs. CG+CC |
0.500 (0.117 - 2.139) |
0.350 |
346.065 |
Overdominant |
CG vs. CC+GG |
0.723 (0.432 - 1.212) |
0.219 |
345.457 |
Additive |
G |
0.682 (0.435 - 1.071) |
0.097 |
344.182 |
TERC rs35073794 |
Codominant |
AG vs. GG AA vs. GG |
- - |
- - |
- |
Dominant |
AG + AA vs. GG |
0.295 (0.173 - 0.503) |
<0.001 |
325.726 |
Recessive |
AA vs. AG+GG |
- |
- |
- |
Overdominant |
AG vs. AA+GG |
0.295 (0.173 - 0.503) |
<0.001 |
325.726 |
Additive |
A |
0.295 (0.173 - 0.503) |
<0.001 |
325.726 |
44 |
TEP1 rs1760904 |
Codominant |
AG vs. AA GG vs. AA |
0.921 (0.437 - 1.937) 1.340 (0.558 - 3.214) |
0.828 0.512 |
238.517 |
Dominant |
AG + GG vs. AA |
1.033 (0.511 - 2.088) |
0.929 |
237.452 |
Recessive |
GG vs. AG + AA |
1.417 (0.691 - 2.903) |
0.341 |
236.564 |
Overdominant |
AG vs. AA+GG |
0.800 (0.435 - 1.472) |
0.474 |
236.946 |
Additive |
G |
1.154 (0.741 - 1.799) |
0.526 |
237.057 |
TEP1 rs1713418 |
Codominant |
AG vs. AA GG vs. AA |
1.130 (0.556 - 2.296) 2.361 (0.979 - 5.696) |
0.736 0.056 |
235.321 |
Dominant |
AG + GG vs. AA |
1.393 (0.716 - 2.708) |
0.329 |
236.492 |
Recessive |
GG vs. AG+AA |
2.191 (1.020 - 4.708) |
0.044 |
233.436 |
Overdominant |
AG vs. AA+GG |
0.814 (0.442 - 1.497) |
0.507 |
237.019 |
Additive |
G |
1.492 (0.959 - 2.320) |
0.076 |
234.263 |
TERC rs12696304 |
Codominant |
CG vs. CC GG vs. CC |
0.901 (0.476 - 1.705) 0.486 (0.126 - 1.884) |
0.748 0.297 |
238.256 |
Dominant |
CG+GG vs. CC |
0.826 (0.448 - 1.523) |
0.539 |
237.082 |
Recessive |
GG vs. CG+CC |
0.508 (0.135 - 1.917) |
0.318 |
236.359 |
Overdominant |
CG vs. CC+GG |
0.972 (0.521 - 1.815) |
0.930 |
237.452 |
Additive |
G |
0.795 (0.485 - 1.305) |
0.365 |
236.627 |
TERC rs35073794 |
Codominant |
AG vs. GG AA vs. GG |
0.582 (0.314 - 1.080) - |
0.086 - |
234.455 |
Dominant |
AG + AA vs. GG |
0.601 (0.325 - 1.111) |
0.104 |
234.814 |
Recessive |
AA vs. AG+GG |
- |
- |
- |
Overdominant |
AG vs. AA+GG |
0.565 (0.305 - 1.045) |
0.069 |
234.132 |
Additive |
A |
0.650 (0.356 - 1.190) |
0.163 |
235.502 |
Table 8.
Linkage disequilibrium between TEP1 rs1760904 and rs1713418 polymorphisms in patients with MS and control group.
Table 8.
Linkage disequilibrium between TEP1 rs1760904 and rs1713418 polymorphisms in patients with MS and control group.
SNP |
MS group vs. Control group |
D' |
r2 |
p-value |
rs1760904 - rs1713418 |
0.471 |
0.146 |
0.000 |
Table 9.
Haplotype association with the predisposition to MS occurrence.
Table 9.
Haplotype association with the predisposition to MS occurrence.
Haplotype |
TEP1rs1760904 |
TEP1rs1713418 |
Frequency, % |
OR (95% CI) |
p-value |
Control |
MS |
1 |
A |
A |
42.81 |
32.53 |
1.000 |
- |
2 |
G |
G |
31.94 |
29.03 |
1.140 (0.820 - 1.600) |
0.430 |
3 |
G |
A |
17.19 |
24.97 |
1.740 (1.180 - 2.560) |
0.006 |
4 |
A |
G |
8.06 |
13.47 |
1.920 (1.140 - 3.240) |
0.014 |
Table 10.
Linkage disequilibrium between TERC rs12696304 and rs35073794 polymorphisms in patients with MS and control group.
Table 10.
Linkage disequilibrium between TERC rs12696304 and rs35073794 polymorphisms in patients with MS and control group.
SNP |
MS group vs. Control group |
D' |
r2 |
p-value |
rs12696304 - rs35073794 |
0.019 |
<0.001 |
0.631 |
Table 11.
Haplotype association with the predisposition to MS occurrence.
Table 11.
Haplotype association with the predisposition to MS occurrence.
Haplotype |
TERC rs12696304 |
TERCrs35073794 |
Frequency, % |
OR (95% CI) |
p-value |
Control |
MS |
1 |
C |
G |
50.48 |
59.55 |
1.000 |
- |
2 |
C |
A |
22.99 |
19.95 |
0.510 (0.320 - 0.840) |
0.008 |
3 |
G |
G |
15.82 |
17.20 |
0.870 (0.540 - 1.390) |
0.550 |
4 |
G |
A |
10.70 |
3.30 |
0.190 (0.080 - 0.490) |
<0.001 |