NOD2/CARD15 gene mutations in North Algerian patients with inflammatory bowel disease

NOD1 and NOD2 genetic variants: Impact on hepatocellular carcinoma susceptibility and progression in Moroccan population

BACKGROUND

Nucleotide-binding oligomerization domain 1 (NOD1) and NOD2 are involved in carcinogenic processes by recognizing bacterial cell wall components and triggering inflammation. This study explored the association between genetic variations in NOD1 and NOD2 and susceptibility to hepatocellular carcinoma (HCC) and its progression in a Moroccan population.

METHODS

Genotyping of NOD1 rs2075820 (C>T) and NOD2 rs718226 (A>G) was performed using the TaqMan allelic discrimination assay in 467 Moroccan individuals. The cohort included 156 patients with hepatocellular carcinoma (HCC), 155 patients with liver cirrhosis (LC) diagnosed with HBV, HCV, or MASLD, and 156 controls.

RESULTS

The NOD1 rs2075820 variant showed no association with HCC susceptibility or progression, which is consistent with in silico predictions. However, the NOD2 rs718226 G allele and GG genotype were more common in the HCC group compared to the cirrhosis and control groups. Individuals with the homozygous G variant had a 2-fold higher risk for HCC (ORad = 2.12; CI=1.01-4.44; Pad = 0.04). Those with the GG genotype also had an increased risk of HCC (GG vs. AG+AA ORad = 2.28; CI=1.15-4.54; Pad = 0.016). Furthermore, GG genotype carriers had a significantly higher risk of HCC progression (ORad = 2.58; CI=1.26-5.31; Pad​ = 0.031). Individuals with the rs718226 minor allele had a significantly elevated risk of progressing from LC to HCC (ORad = 1.50; CI=1.07-2.09; Pad = 0.016). Stratification analysis indicated that men had a higher risk of HCC progression compared to women (ORad = 4.63; CI=1.53-14.00 vs. ORad = 2.73; CI=1.05-7.09).

CONCLUSION

The NOD1 rs2075820 polymorphism does not appear to be a genetic risk factor for susceptibility to HCC. In contrast, the non-coding NOD2 rs718226 variant significantly increases HCC susceptibility and promotes liver cancer progression in the Moroccan population. Further studies involving larger cohorts are warranted to definitively confirm or refute the effects of NOD1 and NOD2 genetic variants on liver cancer susceptibility and progression.

Ethnic Issues and Disparities in Inflammatory Bowel Diseases: What Can We Learn from the Arab Population in Israel?

Inflammatory bowel diseases are increasing among different ethnic groups. We aimed to compare the clinical characteristics, complications, and outcomes among Arab and Jewish people sharing the same healthcare system. All patients older than 18 years with a diagnosis of Crohn's disease (CD) or ulcerative colitis (UC) between the years 2000 and 2021 were included. Data regarding demographics, disease characteristics, extraintestinal manifestation, treatment, comorbidities, and mortality were retrieved. A total of 1263 (9.8%) Arab CD patients were compared with 11,625 Jewish CD patients, and 1461 (11.8%) Arab UC patients were compared to 10,920 Jewish patients. Arab CD patients were younger at diagnosis, 36.11 ± 16.7 compared to 39.98 ± 19.4 years, p < 0.001, 59.5% males compared to 48.7%, p < 0.001; in addition, Arab CD patients had a higher rate of anal fissure, perianal abscess, erythema nodosum, diabetes mellitus, obesity, liver cirrhosis, and male infertility. Arab CD patients were less frequently treated with azathioprine or mercaptopurine compared with Jewish patients. No significant difference was found in the rate of anti-TNF treatment, but a higher rate of steroids treatment was found. The all-cause mortality of CD patients was lower among Arab patients (8.4% vs. 10.2%, p = 0.039). Significant differences were found regarding disease characteristics, course, comorbidities, and treatment among Arab and Jewish patients with IBD.

Causal Relationship between Physiological and Pathological Processes in the Brain and in the Gastrointestinal Tract: The Brain-Intestine Axis

The brain and gastrointestinal tract are the most important organs responsible for detecting, transmitting, integrating, and responding to signals coming from the internal and external environment. A bidirectional system of neurohumoral communication (the "intestine-brain" axis) combines the activity of the intestine and brain (or brain and intestine) of a person. It affects human development and behavior. This paper analyzes the literature data on the existence of a relationship between the central and enteral nervous systems. Based on data on the number of neurons in the enteral nervous system (approximately 250 million nerve cells), the concept of a "second brain" in the intestine has been proposed in foreign literature, which, by its influence on the brain, can have a more powerful influence than the spinal cord (approximately 10 million neurons) with its autonomic nervous system. However, it turned out that Russian scientists, academicians of the Academy of Sciences of the Soviet Union I.P. Pavlov, K.M. Bykov, and A.M. Ugolev, analyzed cortical-visceral relationships in the 20th century and wrote about the existence of a connection between the central and enteral nervous systems. One of the urgent problems of modern physiology, pathophysiology, biophysics, biochemistry, and medicine is to clarify the causal relationship between the central and enteral nervous systems, as well as between neurological, mental, and gastrointestinal diseases in order to combine the efforts of specialists of various medical and biological profiles to solve urgent medical problems.

Interplay between Serotonin, Immune Response, and Intestinal Dysbiosis in Inflammatory Bowel Disease

Inflammatory Bowel Disease (IBD) is a chronic gastrointestinal disorder characterized by periods of activity and remission. IBD includes Crohn's disease (CD) and ulcerative colitis (UC), and even though IBD has not been considered as a heritable disease, there are genetic variants associated with increased risk for the disease. 5-Hydroxytriptamine (5-HT), or serotonin, exerts a wide range of gastrointestinal effects under both normal and pathological conditions. Furthermore, Serotonin Transporter (SERT) coded by Solute Carrier Family 6 Member 4 (SLC6A4) gene (located in the 17q11.1-q12 chromosome), possesses genetic variants, such as Serotonin Transporter Gene Variable Number Tandem Repeat in Intron 2 (STin2-VNTR) and Serotonin-Transporter-linked promoter region (5-HTTLPR), which have an influence over the functionality of SERT in the re-uptake and bioavailability of serotonin. The intestinal microbiota is a crucial actor in normal human gut physiology, exerting effects on serotonin, SERT function, and inflammatory processes. As a consequence of abnormal serotonin signaling and SERT function under these inflammatory processes, the use of selective serotonin re-uptake inhibitors (SSRIs) has been seen to improve disease activity and extraintestinal manifestations, such as depression and anxiety. The aim of this study is to integrate scientific data linking the intestinal microbiota as a regulator of gut serotonin signaling and re-uptake, as well as its role in the pathogenesis of IBD. We performed a narrative review, including a literature search in the PubMed database of both review and original articles (no date restriction), as well as information about the SLC6A4 gene and its genetic variants obtained from the Ensembl website. Scientific evidence from in vitro, in vivo, and clinical trials regarding the use of selective serotonin reuptake inhibitors as an adjuvant therapy in patients with IBD is also discussed. A total of 194 articles were used between reviews, in vivo, in vitro studies, and clinical trials.

NOD2/CARD15 polymorphisms (P268S, IVS8+158, G908R, L1007fs, R702W) among Kuwaiti patients with Crohn's disease: A case-control study

BACKGROUND

Nucleotide-binding oligomerization domain-containing two (NOD2/CARD15) gene polymorphisms are implicated in the pathogenesis of Crohn's disease (CD).

AIM

To describe the allelic frequency of NOD2/CARD15 gene variants among Kuwaiti patients with CD and investigate potential genotype/phenotype associations.

METHODS

Adult Kuwaiti citizens with an established diagnosis of CD and healthy controls were enrolled from October 2018 to May 2020. Three common NOD2/CARD15 polymorphisms (R702W, G908R, and L1007fs) and P268S and IVS8⁺¹⁵⁸ polymorphisms were screened by polymerase chain reaction/restriction analysis length polymorphism (PCR/RFLP).

RESULTS

Ninety adult Kuwaiti patients with CD and 210 healthy subjects (as controls) were recruited. P268S, IVS8⁺¹⁵⁸, G908R, and R702W minor alleles were identified in 38.9%, 21.1%, 12.2%, and 4.4% of CD patients, respectively. NOD2/CARD15 polymorphisms coexisted in 35 healthy controls (16.7%) and 21 CD patients (23.3%). Individuals with either a single or multiple polymorphism were approximately two times more likely to have CD than those with no polymorphism. Patients with multiple polymorphisms had significantly more stricturing and penetrating disease.

CONCLUSION

NOD2/CARD15 gene polymorphisms were significantly associated with an increased risk of disease and aggressive phenotypes among the Kuwaiti CD population.

Gene Polymorphisms of NOD2, IL23R, PTPN2 and ATG16L1 in Patients with Crohn's Disease: On the Way to Personalized Medicine?

Genetic and environmental factors are involved in the pathogenesis of inflammatory bowel diseases (IBD). The study aimed at investigating the potential influence of single nucleotide polymorphisms (SNPs) NOD2 rs2066844, NOD2 rs2066845, NOD2 rs2066847, IL23R rs11209026, PTPN2 rs2542151, PTPN2 rs7234029, and ATG16L1 rs2241880 on the response to immunomodulatory therapies and disease course in Crohn’s disease (CD). This is an uncontrolled retrospective monocentric study including patients from the IBD outpatient clinic of Heidelberg University Hospital. Therapy responses and disease courses were related to genetic findings. 379 patients with CD were included. The presence of at least one PTPN2 rs7234029 risk allele was associated with nonresponse to anti-interleukin-12/23 treatment (89.9% vs. 67.6%, p = 0.005). The NOD2 rs2066844 risk allele was associated with a first-degree family history of colon cancer (12.7% vs. 4.7%, p = 0.02), the ATG16L1 rs2241880 risk allele with ileal CD manifestation (p = 0.027), and the IL23R rs11209026 risk allele with a higher rate of CD-related surgeries per disease year (0.08 vs. 0.02, p = 0.025). The results of this study underline the relevance of genetic influences in CD. The association of the PTPN2 rs7234029 risk allele with nonresponse to anti-interleukin-12/23 treatment in CD patients is a novel finding and requires further investigation.

Inflammatory bowel disease in Africa: what is the current state of knowledge?

Inflammatory bowel disease (IBD) is increasingly recognized as a global disease in the twenty-first century; however, little is known about its epidemiology in Africa. We conducted a literature review in order to assess what is currently known on this subject, the results of which are reported here. Based on available observational studies, it appears that the incidence of IBD in Africa is rising, although comprehensive epidemiological data are lacking. This is likely due to multiple factors, including shifting trends in diet and exposure to environmental pathogens. Many challenges relating to IBD exist for healthcare systems in Africa, including the need for improved access to diagnostic facilities such as endoscopy and histopathology, and the potential economic burden of treatment. Intestinal TB also represents a significant confounding factor in the diagnosis of IBD in Africa.

Non-radiographic axial spondyloarthritis in Tunisia: main characteristics and detailed comparison with ankylosing spondylitis

OBJECTIVES

The aim of the present study is to compare the clinical features, disease activity, and physical impairment between non-radiographic axial spondyloarthritis and ankylosing spondylitis in Tunisian patients.

METHODS

This is a retrospective study conducted in a single rheumatology center in Tunisia. Patients with axial spondyloarthritis fulfilling the 2009 ASAS criteria were included. The various spondyloarthritis-related variables were compared between non-radiographic axial spondyloarthritis and ankylosing spondylitis. p Values below 0.05 were considered statistically significant.

RESULTS

Among 200 patients with axial spondyloarthritis, 40 had non-radiographic axial spondyloarthritis and 160 had ankylosing spondylitis. The non-radiographic axial spondyloarthritis patients were more frequently female, were younger, and had shorter disease duration. Patients with non-radiographic axial spondyloarthritis experienced enthesitis more frequently compared with ankylosing spondylitis patients. Psoriasis was more frequent in non-radiographic axial spondyloarthritis group, while inflammatory bowel disease was more frequent in ankylosing spondylitis group. The C-reactive protein level and functional score were significantly higher in patients with ankylosing spondylitis compared with non-radiographic axial spondyloarthritis. Tumor necrosis factor inhibitors were offered significantly more often to the ankylosing spondylitis group. There was no statistically significant difference between the 2 groups in other spondyloarthritis parameters.

CONCLUSION

The non-radiographic axial spondyloarthritis is characterized mainly by a marked female prevalence, a higher enthesitis prevalence, and a better physical function.

KEY POINTS

• Patients with nr-axSpA in Tunisia are more frequently female and have shorter disease duration compared with those with AS. • Peripheral manifestations were similar between nr-axSpA and AS patients except for enthesitis which were more frequent within nr-axSpA patients. • The disease activity is similar between the 2 groups of axSpA but the physical function is better within nr-axSpA patients.

Genetic polymorphisms present in IL10, IL23R, NOD2, and ATG16L1 associated with susceptibility to inflammatory bowel disease in Mexican population

OBJECTIVE

Ulcerative colitis and Crohn's disease are the two clinical forms of inflammatory bowel disease (IBD). Diverse studies have shown the association of single nucleotide polymorphism (SNP) in molecules of the immune system and the occurrence of IBD. Here, several SNPs of the immune system with controversial results for their association with UC and CD were evaluated in a Mexican population.

METHODS

SNPs rs1800896, rs3024505 (IL-10); rs11209026 (IL23R); rs2066844, rs2066845 (NOD-2), and rs2241880 (ATG16L1) were assessed in 93 patients with IBD and 200 healthy controls by hybridization probes and quantitative PCR.

RESULTS

The AG genotype for rs1800896 was associated with an increased risk for both UC and CD (P = 0.005 and P = 0.026, respectively); whereas the AA genotype presents a negative association (P = 0.011 for UC, and 0.0038 for CD). For this SNP, G allele was associated with risk of UC (P = 0-043) but not for CD. For the rs3024505 in IL-10, T allele was associated with UC (P = 0.011). Moreover, this allele was associated with early onset of UC (P = 0.033) and with the use of steroid treatment (P = 0.019). No significant differences for NOD2 (rs2066844T and rs2066845C), IL23R (rs11209026), and ATG16L1 (rs22411880) were found between cases and controls and the homozygous TT genotype for rs2066844 and CC for rs2066845 were not observed.

CONCLUSION

Our results show both genotypic and phenotypic associations of IL-10 SNPs with IBD but not with the other immune-related SNPs studied in this Mexican cohort.

Identifying the Neurogenetic Framework of Crohn's Disease Through Investigative Analysis of the Nucleotide-binding Oligomerization Domain-containing Protein 2 Gene Mutation

Among several inflammatory bowel diseases, Crohn's disease is associated with inflammation that may take place in any region of the gastrointestinal tract. The inflammatory process is most commonly associated with the ileum, often spreading deep into the bowel tissues, extending into multiple forms, such as strictures and penetrations. Currently, Crohn's disease has no known cure. Various medical and surgical procedures are used to manage the condition. The underlying mechanisms of the disease are yet to be identified, with recent studies suggesting the influence of genetics, environmental factors, and the possible activity of pathogens. Newer studies also offer strong evidence that suggests a relationship between Crohn's disease and the nucleotide-binding oligomerization domain-containing protein 2 (NOD2) gene, also known as inflammatory bowel disease protein 1 (IBD1) or caspase recruitment domain-containing protein 15 (CARD15). NOD2 is responsible for the mechanism in which the immune system identifies foreign microorganisms through the sensing of pathogen-associated molecular patterns in microorganisms. NOD2 can detect intracellular muramyl dipeptide (MDP) in the bacterial wall, thereby causing an inflammatory response. Three major mutations associated with the NOD2 gene are known to have an influence on Crohn's disease (SNP8, SNP12, and SNP13). This article will discuss a number of studies to identify whether there is a relationship between Crohn's disease and the NOD2 gene.

Single Nucleotide Polymorphisms in Selected Genes in Inflammatory Bowel Disease

Introduction

Inflammatory bowel disease (IBD) is a complicated, multifunctional disorder characterized by chronic, recurring inflammation of the digestive tract. The two main types of IBD are ulcerative colitis (UC) and Crohn's disease (CD). The aim of the study was to determine single nucleotide polymorphism in fragments of the genes CARD15/NOD2 and DLG5 in patients from the Lublin Voivodeship.

Patients and Methods

The study was carried out in Lublin (Poland) in 2016. 27 individuals participated in the research. The research group comprised 9 patients with a diagnosis of Crohn's disease and 9 with ulcerative colitis, aged 20 to 48, and 9 healthy volunteers.

Results

No SNPs were confirmed for the CARD15/NOD2 gene fragment, but a substitution (T>C) was found in the DLG5 gene in a Crohn's disease patient.

Conclusion

Absence of extraintestinal symptoms in patients with Crohn's disease may be associated with the absence of CARD15/NOD2 SNPs. The study suggests that SNPs (T>C substitution) affect the function of the DLG5 protein and thus play a role in the development of IBD, in particular Crohn's disease. The analysis presented is a pilot study due to the small number of samples.

Clinical variables and ethnicity may influenced by polymorphism of CAT -262C/T and MnSOD 47C/T antioxidant enzymes in Algerian type1 diabetes without complications

The latest studies in Algeria show that the frequency of type 1 diabetes (T1D) without complications is lower than that with complications and represents a significant burden in terms of cost and treatment. For this reason, we are interested in uncomplicated type1 diabetes and risk factors that are related to polymorphisms of antioxidant enzymes in order to prevent its complications. A total of 260 blood samples of young Algerian adults were examined. The genotypic analysis of Catalase gene (CAT -262C/T, rs1001179) and the superoxide dismutase gene (MnSOD 47C/T, rs4880) was performed by real-time PCR using TaqMan technology. The genotypic distribution of the CAT -262C/T promoter gene's polymorphism showed a significant difference between control and T1D patients for the CC genotype (p = 0.009; OR = 0.30) and for the T allele (p = 0.002; OR = 2.82). In addition, the genotypic distribution of the MnSOD 47C/T gene showed an association with T1D for the CT genotype (p = 0.040; OR = 2.37). Our results revealed that polymorphisms of CAT and MnSOD may be associated with physiopathology causing the onset of T1D. Our data, suggest that the genotypic frequencies of these SNPs appear to be influenced by clinical variables and by the Arab-Berber ethnic origin of the Algerian population.

Targeted Gene Sequencing in Children with Crohn's Disease and Their Parents: Implications for Missing Heritability

Crohn’s disease is a complex genetic trait characterized by chronic relapsing intestinal inflammation. Genome wide association studies (GWAS) have identified more than 170 loci associated with the disease, accounting for ∼14% of the disease variance. We hypothesized that rare genetic variation in GWAS positional candidates also contribute to disease pathogenesis. We performed targeted, massively-parallel sequencing of 101 genes in 205 children with Crohn’s disease, including 179 parent-child trios and 200 controls, both of European ancestry. We used the gene burden test implemented in VAAST and estimated effect sizes using logistic regression and meta-analyses. We identified three genes with nominally significant p-values: NOD2, RTKN2, and MGAT3. Only NOD2 was significant after correcting for multiple comparisons. We identified eight novel rare variants in NOD2 that are likely disease-associated. Incorporation of rare variation and compound heterozygosity nominally increased the proportion of variance explained from 0.074 to 0.089. We estimated the population attributable risk and total heritability of variation in NOD2 to be 32.9% and 3.4%, respectively, with 3.7% and 0.25% accounted for by rare putatively functional variants. Sequencing probands (as opposed to genotyping) to identify rare variants and incorporating phase by sequencing parents can recover a portion of the missing heritability of Crohn’s disease.

T300A variant of AT16L1 gene in a cohort of Algerian Crohn disease patients

The T300A variant is among the most Crohn's disease (CD) associated genetic variants. The aim of our study is to bring a first insight about the contribution of the T300A variant in a cohort of Algerian CD. In a case/control design, 118 Algerian CD patients and 161 unrelated healthy subjects were genotyped for the T300A variant using the allelic discrimination test by Applied Biosystems Taqman^® genotyping technology. A serological analysis was carried out using Biosystems™ ELISA kit for the assessment of the anti-Saccharomyces cerevisiae antibodies and immunofluorimetry via Luminex^® technology for the evaluation of cytokine levels (TNFα, IFNγ, IL-6 and IL-17). The comparison between allelic and genotypic frequencies was performed using the χ² test and the exact Fischer test. The odds ratio (OR) was noted adopting confidence interval of 95%. The comparison between the averages was carried out by the Mann-Whitney and Kruskal-Wallis tests. A factorial discriminant analysis and a binary logistic regression were performed as further analyses. The T300A variant showed an increased risk of CD within homozygous variant carriers (P=0.027). Moreover, the carriage of the G allele was associated with the early onset of CD (P=0.01) and a severe CD impairment (P=0.045). We were not able to comfort the association of the T300A variant and ASCA IgA, ASCA IgG and IFNγ levels detected at the univariate analysis. Our results suggest a possible association between the T300A variant and CD in this cohort of Algerian CD patients. Moreover, this variant might be incriminated in the early onset of CD and a severe disease impairment. At the serological study, the univariate and the multivariate analyses yielded contradictory results. Further investigations of larger cohorts of Algerian CD are needed to better assess the suggested associations at the present study.

Genetic association and phenotypic correlation of TLR4 but not NOD2 variants with Tunisian inflammatory bowel disease

OBJECTIVE

The common association between NOD2/CARD15 and TLR4 gene variants with inflammatory bowel disease (IBD) has not been replicated in all studies. We studied the polymorphism of these two genes in Tunisian patients with IBD.

METHODS

Polymorphisms of NOD2 (R702W, G908R and L1007fs) and TLR4 (Asp299Gly and Thr399Ile) genes were analyzed in 106 patients with IBD (68 with ulcerative colitis [UC], 38 with Crohn's disease [CD]) and 160 healthy controls using polymerase chain reaction-restriction fragment length polymorphism. Genotypes and phenotypes were correlated.

RESULTS

The mutated allele of TLR4-Thr399Ile was strongly associated with IBD (9.4% in IBD, 7.4% in UC and 13.2% in CD vs 2.5% in controls; P = 0.0004, 0.014 and 0.00006, respectively). Heterozygous genotypes were significantly more frequent in patients with IBD (17.0%), UC (14.7%) and CD (21.1%) than in controls (5.0%) (P = 0.0012, 0.012 and 0.001, respectively). Interestingly, the wild genotype was found to be protective (odds ratio 0.24). The mutated allele of TLR4-Asp299Gly was more frequent in controls (6.8%) than in patients with IBD (2.9%). A phenotypic correlation of Asp299Gly-AG genotype with arthritis in UC patients was detected (P = 0.003). Regarding the NOD2 gene, the common variations studied were not polymorphic and there was no genetic association with IBD.

CONCLUSION

The TLR4-Thr399Ile variant was strongly associated with susceptibility to IBD, whereas TLR4-Asp299Gly seems to play a role in the clinical expression of UC. The rarity and non-association of NOD2 mutations with IBD may reveal a genetic characteristic of the population in our region.

Impact of NOD2/CARD15 polymorphisms on response to monoclonal antibody therapy in Crohn's disease: a systematic review and meta-analysis

OBJECTIVE

Crohn's disease (CD) is frequently treated with anti-tumor necrosis factor (TNF)α monoclonal antibodies, and NOD2/CARD15 polymorphisms have been reported to predict treatment response. The purpose of this study was to perform a meta-analysis to determine the effect of NOD2/CARD15 polymorphisms on treatment response in patients with CD.

METHODS

Medline, Cochrane, EMBASE, and Google Scholar databases were searched until 19 December 2015 using the keywords: NOD2, CARD15, polymorphism, Crohn's disease. Randomized controlled trials, prospective, retrospective, and cohort studies of patients with CD who received NOD2/CARD15 genetic analysis and were treated with monoclonal antibodies were included. The primary outcome was treatment response.

RESULTS

Of 104 records identified, only four studies were relevant and included in the analysis. The four studies included 355 patients with CD, patient age ranged from 35 to 41 years, and the proportion of males ranged from 33% to 38%; however, only two studies reported age and sex data. Patients were treated with adalimumab and/or infliximab. Analysis revealed that NOD2/CARD15 mutations were not significantly associated with response to adalimumab or infliximab treatment (pooled odds ratio [OR] = 1.35, 95% confidence interval [CI]: 0.78 to 2.32, p = .278).

CONCLUSIONS

NOD2/CARD15 polymorphisms do not predict response to adalimumab and infliximab in patients with CD. However, the number of included studies was small and treatment protocols varied. Further studies are necessary to determine the role of NOD2/CARD15 polymorphisms in patients with CD.

Genetic variations of NOD2 and MD2 genes in hepatitis B virus infection

OBJECTIVES

Nucleotide oligomerization domain 2 (NOD2) and myeloid differentiation protein 2 (MD-2) have crucial roles in the innate immune system. NOD2 is a member of the NOD-like receptor (NLR) family of pattern recognition receptors (PRRs), while MD-2 is a co-receptor for Toll-like receptor 4 (TLR4), which comprises another group of PRRs. Genetic variations in the NOD2 and MD-2 genes may be susceptibility factors to viral pathogens including hepatitis B virus (HBV). We investigated whether polymorphisms at NOD2 (rs2066845 and rs2066844) or at MD-2 (rs6472812 and rs11466004) were associated with susceptibility to HBV infection and advancement to related liver complications in a Saudi Arabian population. Methods: A total of 786 HBV-infected patients and 600 healthy uninfected controls were analyzed in the present study. HBV-infected patients were categorized into three groups based on the clinical stage of the infection: inactive HBV carriers, active HBV carriers, and patients with liver cirrhosis + hepatocellular carcinoma (HCC). Results: All four SNPs were significantly associated with susceptibility to HBV infection although none of the SNPs tested in NOD2 and MD-2 were significantly associated with persistence of HBV infection. We found that HBV-infected patients that were homozygous CC for rs2066845 in the NOD2 gene were at a significantly increased risk of progression to HBV-related liver complications (Odds Ratio = 7.443 and P = 0.044). Furthermore, haplotype analysis found that the rs2066844-rs2066845 C-G and T-G haplotypes at the NOD2 gene and four rs6472812-rs11466004 haplotypes (G-C, G-T, A-C, and A-T) at the MD-2 gene were significantly associated with HBV infection in the affected cohort compared to those found in our control group. Conclusion: We found that the single nucleotide polymorphisms rs2066844 and rs2066845 at NOD2 and rs6472812 and rs11466004 at MD-2 were associated with susceptibility to HBV infection in a Saudi population.