XRCC1 Arg399Gln and Arg194Trp polymorphisms and risk of systemic lupus erythematosus in an Iranian population: a pilot study

Genetic and biochemical studies of hepatic carcinoma in the Egyptian population

Background

Hepatocellular carcinoma (HCC), a deadly malignancy of the liver, is considered the third leading reason behind cancer deaths. It is more frequent in men than in women of ages above 50. Liver disease, leading to liver cirrhosis (LC), is mostly caused by alcoholism abuse, reaction diseases of the liver, or viral hepatitis B or C infection. Interleukin-6 (IL-6) is considered an effective pro-inflammatory cytokine, which plays a crucial role in the host defense mechanism. Its level is higher in HCC patients than in LC cases, indicating that tumor cells increase the production of cytokines. The X-ray repair cross-complementing group 1 (XRCC1) gene is a major DNA repair gene. It acts as a scaffold of various activities that are concerned in the repairing method by interacting with components of base excision repair. This study aims to measure the serum concentrations of IL6 and C-reactive protein (CRP) and investigate whether XRCC1 Arg194Trp and Arg399Gln polymorphisms are related to HCC disease.

Materials and Methods

Whole-blood DNA was extracted from 123 HCC patients and 123 healthy volunteers. Tetra-primer amplification refractory mutation system was performed in the detection of XRCC1 Arg399Gln and Arg194Trp polymorphisms.

Results

Serum concentration levels of IL-6 and CRP are significantly higher in patients with HCC than in control subjects. The allelic and genotype frequency distributions of XRCC1 (Arg399Gln and Arg194Trp) are significantly increased in HCC cases compared to healthy volunteers.

Conclusion

Arg/Gln, Arg/Trp, Gln/Gln, and Trp/Trp genotypes are associated with higher risk HCC than the Arg/Arg genotype.

Gene Polymorphism of XRCC1 in Systemic Lupus Erythematous

Introduction:

There are debates about the role of the X-ray repair cross-complementation group 1 (XRCC1) Arg399Gln gene in the pathogenesis of Systemic Lupus Erythematosus (SLE).

Methods:

The study was a case-control study carried out on 100 recently diagnosed SLE patients compared to 100 control subjects. The study of XRCC1 Arg399Gln polymorphism was performed by a polymerase chain reaction and restriction fragment length polymorphism.

Results and Discussion:

A higher frequency of ‘G’ allele in SLE (38.5%) versus control (32%) was noticed; however, this difference was not statistically significant (p = 0.174). Besides, a slightly higher frequency of G/G genotype was found in SLE (22%) vs. control (12%); again, this difference was not statistically significant (p = 0.157). A statistically significantly higher proportion of arthritis, serositis, and thrombocytopenia was observed in the A/A genotype (p = 0.010, 0.032, and 0.036, respectively). Furthermore, we noticed a statistically significant lower hemoglobin level in G/G genotype (p = 0.027). Otherwise, there was no statistically significant difference between the three genotypes regarding other parameters: photosensitivity, malar rash, oral ulceration, ANA, anti-dsDNA antibody, anemia, leucopenia, neurologic manifestations, and all lab parameters except hemoglobin level. Similar results were reported previously.

According to genotype, in the study of Clinical and laboratory parameters in SLE patients, a statistically significantly higher proportion of arthritis, serositis, and thrombocytopenia was observed in the A/A genotype (p =0 .01, 0.032, and 0.036 respectively). Furthermore, we noticed a statistically significant lower hemoglobin level in G/G genotype (p = 0.027). These findings suggest a pathogenic connection between the seriousness of the defective DNA repair and the autoimmune severity; such connection is consistent with that found in several murine models. Additionally, negative regulation of the genes encoding the proteins involved in the NER pathway in SLE patients, specifically and XPC, has been found previously.

Conclusion:

The present study highlights the higher insignificant increase of G allele and GG genotype of XRCC1 399 gene in patients with SLE compared to healthy control. This increase was significantly associated with anemia in patients, which may reflect the aggravation of environmental risk factors to SLE associated with the reduced repair of DNA. Further longitudinal studies are required to validate the present findings.

Polymorphism of the DNA repair gene XDP increases the risk of systemic lupus erythematosus but not multiple sclerosis in the Iranian population

BACKGROUND

Xeroderma pigmentosum group D ( XPD ) is an essential component of the nucleotide excision repair (NER) pathway, which can play a major role in DNA repair processes. A deficiency in this pathway was suggested as a causative factor of autoimmune diseases. Therefore, the current study aimed to investigate the relationship between XPD Lys751Gln polymorphism (rs13181) as one of the most common XDP polymorphisms and the risk of two important auto-immune diseases,namely systemic lupus erythematosus (SLE) and multiple sclerosis (MS) in the Iranian population.

METHODS

165 SLE patients and 165 age- and gender-matched healthy controls, and 150 MS patients and 150 age- and gender-matched healthy controls were genotyped for XPD rs13181 A/C polymorphism using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method.

RESULTS

The results of the present study have indicated that both C allele frequency ( P = 0.012; odds ratio: 1.5; 95% confidence interval: 1.1-2.07) and CC genotype ( P = 0.007; odds ratio: 2.46; 95% confidence interval: 1.2-4.7) in SLE patient were significantly higher than those in control group. Furthermore, there were no significant differences between MS patients and normal subjects concerning the genotype and the allele frequencies.

CONCLUSION

Our findings suggested that XPD rs13181 A/C polymorphism may be a crucial risk factor for the development of SLE but not MS in Iranian patients.

Genetic and molecular biology of systemic lupus erythematosus among Iranian patients: an overview

BACKGROUND

Systemic lupus erythematosus (SLE) is a clinicopathologically heterogeneous chronic autoimmune disorder affecting different organs and tissues. It has been reported that there is an increasing rate of SLE incidence among Iranian population. Moreover, the Iranian SLE patients have more severe clinical manifestations compared with other countries. Therefore, it is required to introduce novel methods for the early detection of SLE in this population. Various environmental and genetic factors are involved in SLE progression.

MAIN BODY

In present review we have summarized all of the reported genes which have been associated with clinicopathological features of SLE among Iranian patients.

CONCLUSIONS

Apart from the reported cytokines and chemokines, it was interestingly observed that the apoptosis related genes and non-coding RNAs were the most reported genetic abnormalities associated with SLE progression among Iranians. This review clarifies the genetics and molecular biology of SLE progression among Iranian cases. Moreover, this review paves the way of introducing an efficient panel of genetic markers for the early detection and better management of SLE in this population.

Vitamin D Receptor rs2228570 and rs731236 Polymorphisms are Susceptible Factors for Systemic Lupus Erythematosus

Background:

The Vitamin D receptor (VDR) polymorphisms are the candidate genetic variants for susceptibility to different disease including autoimmune disorders. In the present study, we aimed to assess the association between VDR polymorphisms and systemic lupus erythematosus (SLE) susceptibility in Southeast Iranian population.

Materials and Methods:

One hundred and twenty-seven patients with SLE and 139 controls were genotyped for VDR rs2228570, rs731236, and rs7975232 polymorphisms using polymerase chain reaction-restriction fragment length polymorphism method.

Results:

The VDR rs2228570 polymorphism was associated with higher risk of SLE in codominant, dominant, and overdominant models. Moreover, higher risk of SLE was observed in individuals with VDR rs731236 polymorphism in codominant, dominant, overdominant, and allelic models. The tAf haplotype of rs731236/rs7975232/rs2228570 polymorphisms was associated with higher risk of SLE.

Conclusion:

In conclusion, VDR rs2228570 and rs731236 polymorphisms and tAf haplotype were associated with SLE risk.

Association of Polymorphisms in the DNA Repair Genes XRCC1 and XRCC3 with Systemic Lupus Erythematosus

Background:

Evidence suggests that DNA damage is implicated in the development of Systemic Lupus Erythematosus (SLE).

Objective:

Investigate the possible association of polymorphisms in the DNA repair genes XRCC1 and XRCC3 with SLE and its clinical and laboratory features.

Methods:

This is a case-control study comparing the polymorphisms in the DNA repair genes XRCC1 and XRCC3 in SLE patients and control individuals. Genotyping for DNA repair genes was performed by polymerase chain reaction-restriction fragment length polymorphism in 76 patients and 82 healthy control individuals.

Results:

Our data indicated that the genotype frequencies in patients with the XRCC1 Arg399Gln and XRCC3 Thr241Met polymorphisms were similar to those observed in the control group (p > 0.05). However, the frequencies of the 399Gln allele (p = 0.023, OR = 0.58, 95% CI = 0.36–0.93) and 241Met allele (p = 0.0039, OR = 0.59, 95% CI = 0.36–0.98) were significantly lower in the patients than those in the control subjects.

Conclusion:

We demonstrated that 399Gln and 241Met alleles may play a protective role in SLE susceptibility.

DNA Damage and Deficiencies in the Mechanisms of Its Repair: Implications in the Pathogenesis of Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a perplexing and potentially severe disease, the pathogenesis of which is yet to be understood. SLE is considered to be a multifactorial disease, in which genetic factors, immune dysregulation, and environmental factors, such as ultraviolet radiation, are involved. Recently, the description of novel genes conferring susceptibility to develop SLE even in their own (monogenic lupus) has raised the interest in DNA dynamics since many of these genes are linked to DNA repair. Damage to DNA induces an inflammatory response and eventually triggers an immune response, including those targeting self-antigens. We review the evidence that indicates that patients with SLE present higher levels of DNA damage than normal subjects do and that several proteins involved in the preservation of the genomic stability show polymorphisms, some of which increase the risk for SLE development. Also, the experience from animal models reinforces the connection between DNA damage and defective repair in the development of SLE-like disease including characteristic features such as anti-DNA antibodies and nephritis. Defining the role of DNA damage response in SLE pathogenesis might be strategic in the quest for novel therapies.

Association of XRCC1 Arg399GIn and Tp53 Arg72Pro polymorphisms and increased risk of uterine leiomyoma - A case-control study

The aim of present study was to investigate the role of the X-ray repair cross-complementing protein1 (XRCC1) and Tumor protein p53 (Tp53) polymorphisms in Uterine Leiomyoma (UL) susceptibility in southeastern Iran. This case control study was performed on 139 women with UL and 149 age, BMI and ethnicity matched healthy women. All women were genotyped for the XRCC1 Arg399Gln, XRCC1 Arg194Trp and Tp53 Arg72Pro polymorphisms. The frequency of Tp53 72 Pro/Pro genotype was significantly higher in UL women compared to controls. The risk of UL was 1.5 fold higher in women with the Pro/Pro genotype (OR, 1.5 [95% CI, 1.1 to 2.1], p = 0.012). Moreover, the frequency of the Pro allele was significantly higher in the UL women. Although the frequency of XRCC1 Arg399Gln genotypes did not significantly differ between UL and control groups before adjusting for age, there was an association between the XRCC1 Arg/Gln genotype and UL after adjusting for age (OR, 1.8 [95% CI, 1.1 to 3]). No association was observed between the XRCC1 Arg194Trp polymorphism and UL. The Pro/Pro genotype of Tp53 Arg72Pro polymorphism was associated with UL susceptibility. In addition, the XRCC1 Arg/Gln genotype was associated with increased risk of UL after adjusting for age.

Worldwide Distribution of Four SNPs in X-Ray and Repair and Cross-Complementing Group 1 (XRCC1)

PURPOSE

X-ray repair cross-complementing group 1 (XRCC1) repairs single-strand breaks in DNA. Several reports have shown the association of single nucleotide polymorphisms (SNPs) (Arg194Trp, Pro206Pro, Arg280His, Arg399Gln) in XRCC1 to diseases. Limited population data are available regarding SNPs in XRCC1, especially in African populations. In this study, genotype distributions of four SNPs in worldwide populations were examined and compared with those reported previously.

MATERIALS AND METHODS

Four SNPs (Arg194Trp, Pro206Pro, Arg280His, Arg399Gln) in XRCC1 from genomic DNA samples of 10 populations were evaluated by using polymerase chain reaction followed by restriction fragment length polymorphism analysis.

RESULTS

The frequency of the minor allele corresponding to the Trp allele of XRCC1Arg194Trp was higher in Asian populations than in African and Caucasian populations. As for XRCC1Pro206Pro, Africans showed higher minor allele frequencies than did Asian populations, except for Tamils and Sinhalese. XRCC1 Arg280His frequencies were similar among Africans and Caucasians but differed among Asian populations. Similarly, lower mutant XRCC1 Arg399Gln frequencies were observed in Africans.

CONCLUSIONS

This study is the first to show the existence of a certain genetic heterogeneity in the worldwide distribution of four SNPs in XRCC1.