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Background HLA-B*51 has been universally associated with Behcet's disease (BD) susceptibility, while different alleles of HLA-A have also been identified as independent BD susceptibility loci in various ethnic populations. The objective of this study was to investigate associations of HLA-A and - B alleles with BD in Saudi patients. Materials and Methods Genotyping for HLA-A and HLA-B was performed using HLA genotyping kit (Lab type(R) SSO) in 120 Saudi subjects, including 60 BD patients and 60 matched healthy controls. Results Our results revealed that frequencies of HLA-A*26, -A*31, and - B*51 were significantly higher in BD patients than in controls, suggesting that HLA-A*26, -A*31, and - B*51 are associated with BD. The frequency of HLA-B*15 was significantly lower in BD patients than in controls. Stratification of genotyping results into active and nonactive forms of BD revealed that the frequency of HLA-A*31 was significantly higher in the nonactive form than in the active form of BD, while there was no significant difference in the distribution of other alleles between the two forms of BD. Conclusion This study suggests that HLA-A*26, -A*31, and - B*51 are associated with susceptibility risk to BD, while HLA-B*15 may be protective in Saudi patients. However, larger scale studies are needed to confirm these findings.

The cause of atopic dermatitis (AD) is multifactorial and a number of genes including cytokines have been involved. We genotyped 315 subjects for polymorphisms in TNF-α and TNF-β and IL-10 genes. Patients had significantly higher frequency of GA genotype of TNF-α (−308 G/A) than healthy controls. Patients with AD and controls had similar distribution of A and G alleles. Genotype AA was found in 7.11% of controls while completely absent in cases. The frequencies of genotypes GG and AA of TNF-β (+252 A/G) polymorphism were higher whereas the frequency of genotype GA was significantly lower in patients than the controls. The frequencies of genotypes GG and AA of IL-10 (1082 G/A) polymorphism were significantly increased whereas genotype GA was decreased in patients than the controls. It is concluded that TNF-α (−308 G/A), TNF-β (+252 A/G), and IL-10 (−1082 G/A) polymorphisms are linked with the susceptibility of AD in Saudis and can be a risk factor.

Background: Psoriasis is a complex autoimmune disease caused by the interaction of genetic and environmental factors. PTPN22 gene polymorphism has been reported to affect psoriasis susceptibility; however, no data are available for Middle Eastern populations. Objective: The aim of this study was to investigate the association of PTPN22 (1858C/T) R620W polymorphism with psoriasis in a Saudi cohort. Methods: Saudi subjects (n = 306) including patients with psoriasis (n = 106) and matched controls (n = 200) were studied for PTPN22 variants using tetra-primer amplification refractory mutation system-polymerase chain reaction method. The frequencies of alleles and genotypes of PTPN22 (1858C/T) polymorphism were compared between patients and controls. Results: The frequency of CT genotype of PTPN22 (1858C/T) polymorphism was significantly higher, whereas that of CC genotype was lower in patients with psoriasis than in controls ( P Conclusions: PTPN22 (1858C/T) polymorphism is positively associated with susceptibility of psoriasis in Saudis and can be developed as biomarker for evaluating psoriasis risk. However, further studies on PTPN22 polymorphism in larger samples from different geographical areas and ethnicity are warranted.

Background: Psoriasis is a complex autoimmune disease caused by the interaction of genetic and environmental factors. PTPN22 gene polymorphism has been reported to affect psoriasis susceptibility; however, no data are available for Middle Eastern populations. Objective: The aim of this study was to investigate the association of PTPN22 (1858C/T) R620W polymorphism with psoriasis in a Saudi cohort. Methods: Saudi subjects (n = 306) including patients with psoriasis (n = 106) and matched controls (n = 200) were studied for PTPN22 variants using tetra-primer amplification refractory mutation system-polymerase chain reaction method. The frequencies of alleles and genotypes of PTPN22 (1858C/T) polymorphism were compared between patients and controls. Results: The frequency of CT genotype of PTPN22 (1858C/T) polymorphism was significantly higher, whereas that of CC genotype was lower in patients with psoriasis than in controls ( P

Objectives Oral lichen planus (OLP) is a chronic inflammatory oral mucosal disease. Cytokines play an important role in the pathogenesis and disease progression of OLP. Various reports have implicated cytokine gene polymorphisms in susceptibility to develop some immune mediated conditions including OLP. The purpose of this study was to investigate the association of tumor necrosis factor (TNF)-α, TNF-β and interleukin (IL)-10 gene polymorphisms with the OLP risk. Material and Methods Forty two unrelated patients with OLP and 211 healthy volunteers were genotyped for TNF-α (-308 G/A), TNF-β (+252A/G), IL-10 (-1082G/A), IL-10 (-819C/T), and IL-10 (-592C/A) polymorphisms. Results The frequencies of allele A and genotype GA of TNF-α (-308G/A) were significantly higher while allele G and GG genotypes were lower in OLP patients as compared to the controls (P0.05). However, haplotype ATA extracted from 1082G/A, -819C/T, -592C/A polymorphisms of IL-10 were more prevalent in OLP patients when compared to controls indicating its possible association with OLP susceptibility. Conclusion It is concluded that TNF-α (-308G/A), TNF-β (+252A/G) and IL-10 (-1082G/A, -819C/T and -592C/A) polymorphisms are associated with the susceptibility of OLP, thus giving additional support for the genetic basis of this disease.

INTRODUCTION: Apolipoprotein E (APOE) genotypes influence the phenotype of several neurodegenerative disorders including Alzheimer's and Parkinson disease and may affect schizophrenia pathogenesis. This study was undertaken to determine the association between APOE gene polymorphisms and schizophrenia in the Saudi population. MATERIAL AND METHODS: APOE allele and genotype frequencies were studied in 380 Saudi subjects including schizophrenia patients and matched controls using polymerase chain reaction (PCR) and reverse-hybridization techniques. RESULTS: The frequencies of the APOE allele e2 and genotypes e2/e3 and e2/e4 were significantly higher in the schizophrenia patients as compared to controls, suggesting that the e2 allele and its heterozygous genotypes may increase the susceptibility to schizophrenia. In contrast, the frequencies of the e3 allele and e3/e3 genotype were lower in patients as compared to controls, suggesting a protective effect of APOE e3 for schizophrenia. This study indicated that APOE e4 was differentially associated with schizophrenia depending on the symptoms as the frequency of the e4 allele was significantly higher in schizophrenia patients with positive symptoms. By contrast, no significant association between APOE e4 and schizophrenia patients with negative symptoms was observed. Genotypes e2/e2 and e4/e4 were absent in patients and controls. Moreover, the age of onset was significantly lower in patients with the APOE e2/e3 genotype. There was no significant difference in the frequencies of APOE alleles and genotypes between male and female schizophrenia patients. CONCLUSIONS: The results of this study clearly show that APOE alleles and genotypes are associated with risk of developing schizophrenia and early age of onset in Saudis.

Objectives: To assess the prevalence of pseudoexfoliation syndrome (PEX), and associated ophthalmic complications among Saudi patients. Methods: The prevalence of PEX and associated ocular co-morbidities were determined among the Saudi patients visiting the Primary Care Clinic of Prince Sultan Military Medical City, Riyadh, Kingdom of Saudi Arabia, between January 2009 and January 2010. A total of 1967 patients were examined biomicoscopically by ophthalmologists to determine the presence of PEX and associated ocular complications. Results: Sixty-nine of the 1967 examined patients (3.5%) showed the presence of PEX with no significant gender difference. There was an age dependent increase in the prevalence of PEX after the age of 50 years. Pseudoexfoliation syndrome was associated with higher intraocular pressure, cataract, and poor vision. There was no significant difference in the prevalence of PEX in male and female Saudi patients. Conclusion: Pseudoexfoliation syndrome is an age-related disorder, and its prevalence increases with age. Further larger population based studies are warranted to assess the prevalence of PEX and associated risk factors. Saudi Med J 2015; Vol. 36 (1): 108-112 http://doi.dx.org/10.15537/smj.2015.1.9121

Saeed Kadasah,1 Misbahul Arfin,2 Sadaf Rizvi,2 Mohammed Al-Asmari,2 Abdulrahman Al-Asmari2 1Department of Psychiatry, 2Division of Molecular Biology & Genetics, Scientific Research Center, Prince Sultan Military Medical City, Riyadh, SaudiArabia Background: Schizophrenia is one of the most common devastating psychiatric disorders that negatively affects the quality of life and psychosocial functions. Its etiology involves the interplay of complex polygenic influences and environmental risk factors. Inflammatory markers are well-known etiological factors for psychiatric disorders, including schizophrenia. Objective: The aim of this study was to investigate the association of proinflammatory cytokine genes, tumor necrosis factor (TNF)-α (-308G/A) and TNF-β (+252A/G) polymorphisms with schizophrenia susceptibility. Subjects and methods: TNF-α and TNF-β genes were amplified using amplification refractory mutation system primers in 180 schizophrenia patients and 200 healthy matched controls recruited from the Psychiatry Clinic of Prince Sultan Military Medical City, Riyadh. The frequencies of alleles and genotypes of TNF-α (-308G/A) and TNF-β (+252A/G) polymorphisms in patients were compared with those in controls. Results: The frequencies of TNF-α (-308) allele A and genotype GA were significantly higher, while those of allele G and genotype GG were lower in schizophrenia patients as compared to controls, indicating that genotype GA and allele A of TNF-α (-308G/A) may increase susceptibility to schizophrenia, while genotype GG and allele G may reduce it. On the other hand, the distribution of alleles and genotypes of TNF-β (+252A/G) polymorphism does not differ significantly in patients from controls; however, the frequency of genotype GG of TNF-β (+252A/G) was significantly higher in male patients than in female patients. The distribution of TNF-α (-308G/A) and TNF-β (+252A/G) polymorphisms was almost similar in schizophrenia patients with negative or positive symptoms. Conclusion: TNF-α (-308G/A) and TNF-β (+252G/A) polymorphisms may increase the susceptibility to schizophrenia in Saudi patients and could be a potential risk factor for its etiopathogenesis. However, further studies are warranted involving a larger sample size to strengthen our findings. Keywords: schizophrenia, tumor necrosis factor, gene polymorphism, genetics, psychiatric disorder

Methylenetetrahydrofolate reductase (MTHFR) has been linked with the etiopathogenesis of psoriasis with inconsistent results. Methylenetetrahydrofolate reductase C677T polymorphism was evaluated in 106 Saudi psoriasis vulgaris patients and 280 matched healthy controls using PCR-RFLP (restriction fragment length plymorphism) technique. The cardiovascular risk factors were also compared in cases and controls. Allele T and genotypes CT and TT were found to be increased while allele C and genotype CC significantly decreased in psoriasis patients as compared with controls ( P

The frequencies of alleles and genotypes of TNF-α, TNF-β, and IL-10 genes were examined in Saudi subjects including IBD patients (UC and CD) and matched controls. Venous blood samples were collected from IBD patients and healthy control subjects, and genomic DNA was extracted using commercially available kit (Qiagen, CA, USA). In order to detect TNF-α (-308G/A), TNF-β (+252A/G), IL-10 (-1082G/A), (-819C/T), and (-592C/A) polymorphisms, the TNF-α, TNF-β, and IL-10 genes were amplified using an amplification refractory mutation systems PCR methodology. Analysis of data showed that the frequencies of alleles and genotype of TNF-α (-308G/A), TNF-β (+252A/G), and IL-10 (-1082G/A), (-819C/T), and (-592C/A) polymorphisms differ between IBD patients and control subjects. Our study clearly indicated that the TNF-α (-308G/A), TNF-β (+252A/G), and IL-10 (-1082 G/A) polymorphisms are associated significantly with the risk of IBD susceptibility while other two, IL-10-819C/T and IL-10-592C/A, polymorphisms are not associated with IBD in Saudi population. However, well-designed epidemiological as well as genetic association studies with large sample size among different ethnicities should be performed in order to have better understanding of this relationship.

Background Oral lichen planus (OLP) is a premalignant mucocutaneous disease in which genetic factors and immune responses play a major role. Cytokines play an important role in the pathogenesis and disease progression of OLP. The aim of this study was to investigate the impact of gene polymorphisms of T helper cell subtype Th1 and Th2 cytokines, interferon-gamma (IFN-γ), interleukin-6 (IL-6) and transforming growth factor (TGF)-β1 on OLP susceptibility in a Saudi cohort. Methods Forty two unrelated patients with OLP and 195 healthy controls were genotyped for IFN-γ (874A/T), IL-6 (174G/C) and TGF-β1 (509C/T) polymorphisms. Results The frequency of genotype AT of IFN-γ (874A/T) was significantly higher while genotype AA was lower in OLP patients as compared to controls (P

Ebtissam Saleh Al-Meghaiseeb,1 Abdulrahman A Al-Robayan,1 Mulfi Mubarak Al-Otaibi,1 Misbahul Arfin,2 Abdulrahman K Al-Asmari2 1Department of Gastroenterology, 2Research Centre, Prince Sultan Military Medical City, Riyadh, Saudi Arabia Abstract: Inflammatory bowel disease (IBD) is a complex, multifactorial, chronic inflammatory disorder of the gastrointestinal tract in which immune dysregulation caused by genetic and/or environmental factors plays an important role. The aim of this case–­control study was to evaluate the association of tumor necrosis factor-alpha (TNF-α) (308) and -β (+252) polymorphisms with susceptibility of IBD. A total of 379 Saudi subjects including 179 IBD patients (ulcerative colitis (UC) =84 and Crohn’s disease (CD) =95) and 200 age- and sex-matched healthy controls were recruited. TNF-a and TNF-b genes were amplified using an amplification refractory mutation systems polymerase chain reaction methodology to detect TNF-α (–308) and -β (+252) polymorphisms. The frequency of the GA genotype of TNF-α (–308G/A) was higher, and the frequencies of the GG and AA genotypes were significantly lower in IBD patients compared with those in controls, indicating that genotype GA-positive individuals are susceptible to IBD and that the GG and AA genotypes exert a protective effect. The frequency of allele A of TNF-α (–308G/A) was significantly higher and that of allele G was lower in IBD patients compared with those in controls, indicating an association of allele A with IBD risk in Saudi patients. On stratification of IBD patients into UC and CD, an almost similar pattern was noticed in both the groups. The results of TNF-β (+252A/G) polymorphisms showed a significant increase in the frequency of the GG genotype in IBD patients, suggesting a positive association of GG genotype with IBD risk. On stratification of IBD patients into UC and CD, the genotype GG of TNF-β was associated with susceptibility risk to UC but not CD. The frequencies of alleles and genotypes of both TNF-α and-β polymorphisms are not affected by sex or type of IBD (familial or sporadic). TNF-α (–308G/A) and TNF-β (+252A/G) polymorphisms are associated with risk of developing IBD in Saudi population. Keywords: tumor necrosis factor, polymorphism, inflammatory bowel disease, Saudis, Crohn’s disease, ulcerative colitis&nbsp

Apolipoprotein E (APOE) is a glycosylated protein with multiple biological properties. APOE gene polymorphism plays a central role in lipid metabolism and has recently been suggested to regulate inflammation. Our objective is to evaluate whether APOE polymorphism affects susceptibility to SLE. APOE genotyping was performed using ApoE StripAssay™ kit. Results indicated significantly higher frequencies of allele ∊4 and genotype ∊3/∊4 and lower frequencies of allele ∊3 and genotype ∊3/∊3 in SLE patients than controls. APOE ∊2 allele was found in three patients, whereas it was absent in controls. The frequencies of allele ∊4 and genotype ∊3/∊4 were significantly higher in SLE patients with renal involvement and those of alleles ∊2, ∊4 and genotypes ∊2/∊3, ∊3/∊4 were higher in patients with neuropsychiatric symptoms. It is concluded that APOE allele ∊4 is associated with susceptibility risk/clinical manifestations of SLE and ∊2 may increase its severity while ∊3 is protective for SLE in Saudis.

Background HLA-B*51 has been universally associated with Behcet's disease (BD) susceptibility, while different alleles of HLA-A have also been identified as independent BD susceptibility loci in various ethnic populations. The objective of this study was to investigate associations of HLA-A and - B alleles with BD in Saudi patients. Materials and Methods Genotyping for HLA-A and HLA-B was performed using HLA genotyping kit (Lab type (R) SSO) in 120 Saudi subjects, including 60 BD patients and 60 matched healthy controls. Results Our results revealed that frequencies of HLA-A*26, -A*31 , and - B*51 were significantly higher in BD patients than in controls, suggesting that HLA-A*26, -A*31 , and - B*51 are associated with BD. The frequency of HLA-B*15 was significantly lower in BD patients than in controls. Stratification of genotyping results into active and nonactive forms of BD revealed that the frequency of HLA-A*31 was significantly higher in the nonactive form than in the active form of BD, while there was no significant difference in the distribution of other alleles between the two forms of BD. Conclusion This study suggests that HLA-A*26, -A*31 , and - B*51 are associated with susceptibility risk to BD, while HLA-B*15 may be protective in Saudi patients. However, larger scale studies are needed to confirm these findings.

The promoter region of human Interleukin −10 gene is highly polymorphic and has been associated with numerous autoimmune diseases. Recent studies have linked vitiligo with defective autoimmune system. This study is aimed to explore a possible association between IL-10 gene polymorphism and vitiligo in Saudi population. This case control study consisted of 184 Saudi subjects including 83 vitiligo patients (40 males, 43 females mean age 27.85 ± 12.43 years) and 101 matched controls. Genomic DNA was extracted from the blood samples of healthy controls and Vitiligo patients visiting out patient clinic of Department of Dermatology, Riyadh Armed Forces Hospital, using QIA ampRDNA mini kit (Qiagen CA, USA). Interleukin-10 gene was amplified by polymerase chain reaction (PCR) using Arms primers to detect any polymorphism involved at positions −592, −819 and −1082.The frequencies of GG genotype at −1082, and CC genotype at positions −592 and 819 were significantly higher in vitiligo patients compared to healthy subjects suggesting that GG and CC genotypes might be susceptible to vitiligo in Saudis. On the other hand genotypes −1082 GA, −819 CT, and −592 CA of IL-10 were more prevalent in healthy controls suggesting protective effects of GA, CT and CA genotypes against vitiligo. This study indicates that the IL-10 gene may play a significant role in the etiology of vitiligo among Saudis.

Background: Interleukin-10 (IL-10) gene is considered as a potential candidate gene in schizophrenia association studies. The polymorphisms on IL-10 gene have been reported to be linked with susceptibility to the development of schizophrenia within consistent results. Aims: The aim of this case-control study was to examine whether the -1082A/G, -819T/C, and -592A/C polymorphisms in IL-10 gene are implicated in schizophrenia development in the Saudi population. Materials and Methods: Molecular genotyping of IL-10 gene polymorphisms was performed to analyze the genotypes and alleles distribution of three single-nucleotide polymorphisms (SNPs) in patients (n = 181) and healthy individuals as control group (n = 211). Results: The frequencies of GA genotype at -1082, and CC genotype at positions -592 and -819 were significantly higher in schizophrenia patients compared to healthy subjects suggesting that GA, CC, and CC genotypes are susceptible to schizophrenia. The ACC haplotype known to be associated with intermediate production of IL-10 are more prevalent in our schizophrenia patients. On the other hand, genotypes -1082 GG, -819 CT, and -592 CA of IL-10 were more prevalent in healthy controls suggesting protective effects of GA, CT, and CA genotypes against schizophrenia. There was no significant association of IL-10 polymorphisms with sex or positive or negative symptoms of schizophrenia. Conclusion: This study indicates that the IL-10 gene polymorphisms play a significant role in the etiology of schizophrenia in Saudi Arabians patients.

Schizophrenia is a complex neuropsychiatric disorder strongly associated with dopamine dysregulation. Catechol-O-methyl-transferase (COMT) is a candidate gene for schizophrenia that encodes an enzyme involved in the metabolic inactivation of dopamine. The COMT Val(158)Met polymorphism has been associated with schizophrenia and has significant inter- and intra-ethnic variations. We examined a possible association between the COMT Val(158)Met polymorphism and schizophrenia in Saudis, taking into account gender and functional symptoms. Saudi subjects including 172 unrelated schizophrenia patients and 177 matched controls were analyzed for allele and genotype distribution of the COMT Val(158)Met polymorphism. We found significant differences in allele and genotype frequencies between patients and controls. The frequencies of Met(158) allele (A) and genotype Val(158)Met (GA) were significantly higher in patients compared to those in controls. On the other hand, the frequencies of Val(158) allele (G) and genotype Val(158)Val (GG) were significantly higher in controls than those in patients. We found a significant association of the COMT Val(158)Met polymorphism with schizophrenia. Moreover, male patients with the COMT Val(158)Met polymorphism had increased risk for schizophrenia compared to female subjects. However, no association was noticed with the COMT Val(158)Met polymorphism and negative or positive symptoms of schizophrenia. These results provide evidence for a role of the COMT Val(158)Met polymorphism in the etiopathophysiology of schizophrenia in Saudi population. It appears that the association of the COMT Val(158)Met polymorphism with schizophrenia is mediated by gender.

Vitiligo is an acquired depigmentary disorder of the skin, characterized by multiple susceptibility loci and genetic heterogeneity. The etiology of vitiligo is unknown but several hypotheses, including an autoimmune origin, have been proposed. Tumor necrosis factor (TNF)-α, a pleiotropic proinflammatory cytokine, has been shown to play a critical role in several autoimmune diseases including vitiligo. The aim of present study was to determine the association of TNF-α and -β gene polymorphisms with vitiligo in Saudi patients. TNF-α and -β genes were amplified in 123 Saudi patients and 200 matched controls using polymerase chain reaction to search for polymorphisms involved at positions -308, and intron 1 +252. The frequency of the TNF-α (-308) GA genotype was higher and the frequencies of the GG and AA genotypes were significantly lower in vitiligo patients compared to controls. These findings suggested that genotype GA-positive individuals at position -308 of TNF-α are susceptible to vitiligo, whereas the GG and AA genotypes might exert a protective effect. The frequency of allele A (TNF-α 2-allele) was significantly higher and that of allele G (TNF-α 1-allele) was lower in vitiligo patients compared to controls, indicating an association of allele A with susceptibility to vitiligo in Saudi patients. The results of our examination of TNF-β (intron 1 +252) polymorphisms showed a significant increase in the frequency of the GG genotype and allele G (TNF-β 1-allele) in vitiligo patients, suggesting a susceptibility of the GG genotype and allele G for vitiligo. By contrast, the high frequency of the GA genotype in controls might indicate a protective effect. The results of the present study strongly support a link between TNF-α (-308) and -β (intron 1 +252) polymorphisms and vitiligo in Saudi patients.

Introduction Apolipoprotein E (APOE) genotypes influence the phenotype of several neurodegenerative disorders including Alzheimer's and Parkinson disease and may affect schizophrenia pathogenesis. This study was undertaken to determine the association between APOE gene polymorphisms and schizophrenia in the Saudi population. Material and methods APOE allele and genotype frequencies were studied in 380 Saudi subjects including schizophrenia patients and matched controls using polymerase chain reaction (PCR) and reverse-hybridization techniques. Results The frequencies of the APOE allele ε2 and genotypes ε2/ε3 and ε2/ε4 were significantly higher in the schizophrenia patients as compared to controls, suggesting that the ε2 allele and its heterozygous genotypes may increase the susceptibility to schizophrenia. In contrast, the frequencies of the ε3 allele and ε3/ε3 genotype were lower in patients as compared to controls, suggesting a protective effect of APOE ε3 for schizophrenia. This study indicated that APOE ε4 was differentially associated with schizophrenia depending on the symptoms as the frequency of the ε4 allele was significantly higher in schizophrenia patients with positive symptoms. By contrast, no significant association between APOE ε4 and schizophrenia patients with negative symptoms was observed. Genotypes ε2/ε2 and ε4/ε4 were absent in patients and controls. Moreover, the age of onset was significantly lower in patients with the APOE ε2/ε3 genotype. There was no significant difference in the frequencies of APOE alleles and genotypes between male and female schizophrenia patients. Conclusions The results of this study clearly show that APOE alleles and genotypes are associated with risk of developing schizophrenia and early age of onset in Saudis.

Rheumatoid arthritis (RA) is a chronic systemic inflammatory disorder of unknown etiology that affects the synovial membrane of multiple joints. The clinical presentation of RA may vary from mild to severe with excessive erosions of periarticular bone leading to the loss of functional capacity. Both genetic and environmental factors are important in the development of this disorder. The genetic contribution to susceptibility for RA is underlined by a three-to four-fold higher concordance percentage for clinically expressed disease in monozygotic twins compared to dizygotic twins. The severity and long term outcome of RA have also been related to various genetic factors. Tumor necrosis factor (TNF), a pro-inflammatory cytokine, is involved in the pathogenesis of a variety of autoimmune disorders, including RA. A large number of studies have been undertaken to determine the role of TNF-α promoter polymorphisms in the pathogenesis of RA. On the other hand few attempts have been made to identify the association between TNF-α (lymphotoxin-alfa) polymorphism and RA. In this narrative review of published literature, an attempt has been made to determine the association between TNF-α promoter polymorphisms at positions –308, –238, –489, –857, –863 and TNF-β at +252 with respect to susceptibility to and severity of RA, as well as response to drug therapy. In spite of intra-and inter-ethnic variations, analysis of data suggests a significant role of TNF-α/TNF-β polymorphisms in determining the susceptibility/severity of RA and responsiveness to anti-TNF drug therapy. The TNF gene polymorphisms may be an interesting target for novel strategies to prevent RA and/or in its early treatment. Further studies using larger samples are needed to pinpoint the regulatory polymorphisms or haplotypes and their effects on the development of certain manifestations in RA.

This study is aimed to examine the association between HLA-DRB1 alleles frequency and schizophrenia in Saudi Arabs.The DRB1 region of major histocompatibility complex was screened by polymerase chain reaction/sequence specific primers (PCR/SSP) in 180 schizophrenia patients and 200 matched controls.The frequency of DRB1*03 was found to be significantly higher in schizophrenia patients as compared to controls, whereas a significantly lower frequency of DRB1*06 was observed in schizophrenia patients as compared to controls. Molecular sub-typing of the most prevalent allele DRB1*03 (30.56%) revealed the presence of DRB1*030101, *030102 alleles.The results of this study suggested a positive association between DRB1*03 (DRB1*030101, DRB1*030102) with schizophrenia and a negative association of DRB1*06 with schizophrenia in Saudi Arabs. However it is not clear whether the DRB1*03 alleles have a direct causal role in the etiology of schizophrenia or if they are in direct linkage disequilibrium with another true susceptibility locus. Since schizophrenia is a complex phenotype, it is expected that many factors might act together to produce the final outcome. Further studies are warranted involving larger population to confirm the observations reported in this study.

Susceptibility and development of Clinostomum complanatum in the chicken (Gallus gallus domesticus) have been studied. The progenetic metacercariae of C. complanatum developed into ovigerous worms in 3 days in the buccal cavity of the chicken and survived only 6–7 days in this experimental host. The susceptibility is influenced by the age, sex and breed/type of the host. Both percent susceptibility and recovery of the worms decreased with increase in the age of the host. The egg laying chickens were found to be least susceptible to the infection. Mature male chickens were more susceptible than the females. The single comb white Leghorn (SCWL) was found to be susceptible while the local type (LT) and the cross breed (SCWL×LT) were not susceptible to C. complanatum. The possible reasons for these variations have been discussed.

Fahda Al-Okaily,1 Misbahul Arfin,2 Seham Al-Rashidi,1 Maysoon Al-Balawi,1 Abdulrahman Al-Asmari2 1Department of Rheumatology, 2Division of Molecular Biology and Genetics, Research Center, Prince Sultan Military Medical City, Riyadh, Saudi Arabia Abstract: Behçet’s disease (BD) is a complex, multisystemic inflammatory disorder of unclear etiology. Single nucleotide polymorphisms in tumor necrosis factor (TNF) and interleukin (IL)-10 genes have been implicated in susceptibility to BD with inconsistent results in several ethnic populations. The aim of this case-control study was to evaluate the association of TNF-α (−308G/A), TNF-β (+252A/G), and IL-10 (−1082G/A, −819C/T, and −592 C/A) polymorphisms with susceptibility of BD in Saudi patients. Molecular genotyping of TNF-α, TNF-β, and IL-10 gene polymorphisms was performed to analyze the alleles and genotypes distribution in 272 Saudi subjects, including BD patients (61) and healthy controls (211). The frequencies of allele A and genotype GA of TNF-α (−308G/A) were significantly higher, whereas those of allele G and genotypes GG were significantly lower in BD patients than controls, indicating that A allele and GA genotype are susceptible, while G allele and GG genotype may be refractory to BD. The distribution of frequencies of alleles and genotype of TNF-β (+252A/G) promoter polymorphism was not significantly different between BD patients and healthy controls. Genotypes 1082GG, −819TT, and 592AA of IL-10 polymorphisms are significantly associated with susceptibility risk of BD, while genotypes 1082AA, 1082GA, 819CC, 819CT, 592CC, and 592CA are resistant to BD. This study indicates that TNF-α (−308G/A) and IL-10 (−1082G/A, −819C/T, and −592C/A) polymorphisms are associated with risk of BD susceptibility in Saudi patients. However, larger scale studies in Saudi population as well as in other ethnicities are needed to confirm this association. Keywords: tumor necrosis factor, interleukin-10, polymorphism, Saudis, Behçet's disease

AIM: To study the association of apolipoprotein E (APOE) polymorphisms with the susceptibility of inflammatory bowel disease (IBD) in Saudi patients. METHODS: APOE genotyping was performed to evaluate the allele and genotype frequencies in 378 Saudi subjects including IBD patients with ulcerative colitis (n = 84) or Crohn’s disease (n = 94) and matched controls (n = 200) using polymerase chain reaction and reverse-hybridization techniques. RESULTS: The frequencies of the APOE e2 allele and e2/e3 and e2/e4 genotypes were significantly higher in IBD patients than in controls (P < 0.05), suggesting that the e2 allele and its heterozygous genotypes may increase the susceptibility to IBD. On the contrary, the frequencies of the e3 allele and e3/e3 genotype were lower in IBD patients as compared to controls, suggesting a protective effect of APOE e3 for IBD. The prevalence of the e4 allele was also higher in the patient group compared to controls, suggesting that the e4 allele may also increase the risk of IBD. Our results also indicated that the APOE e4 allele was associated with an early age of IBD onset. No effect of gender or type of IBD (familial or sporadic) on the frequency distribution of APOE alleles and genotypes was noticed in this study. CONCLUSION: APOE polymorphism is associated with risk of developing IBD and early age of onset in Saudi patients, though further studies with a large-size population are warranted.

HLA complex is composed of several closely linked loci, each containing several alleles, yielding a high expression of polymorphism. Vitiligo, a commonly acquired dermatological disorder, has been associated with different HLA antigens in different ethnic groups. In this study, HLA classes I (HLA-A, B, and C) and II (HLA-DR, DQ) antigens/alleles were analyzed in a group of 80 Saudi subjects consisting of vitiligo patients (40) and matched controls (40). The frequency of antigens of various HLA loci was tested using two-stage microcytotoxicity assays, while the frequency of alleles of HLA-DR was screened by polymerase chain reaction/sequence specific primers (PCR/SSP) method. The frequencies of HLA-B7, B15, Bw6, Cw6, Cw7, and DRB4*010101 were found to be significantly higher in vitiligo patients compared to controls [P = 0.029, 0.015, 0.033, 0.009, 0.043, and 0.015, respectively, with relative risk (RR) ≥ 3, etiologic fraction (EF) ≥ 0.4]. On the other hand, HLA-A9, B5, DQ1, and DRB3*010101 were significantly decreased in vitiligo patients compared to healthy Saudis [P = 0.008, 0.004, 0.028, and 0.04, respectively, with RR < 1 and preventive fraction (PF) < 0.5]. Among the patients, the highest allele frequency was noted for DRB4*010101(70%), while in controls it was for DRB3*010101 (72.5%). These results for antigens and allele frequency of various HLA Loci in vitiligo patients and control subjects suggested that HLA-B7, Bw6, Cw6, Cw7, and DRB4*010101 could be susceptible to vitiligo, while HLA-A9, B5, DQ1, and DRB3*010101 might be negatively associated with the development of vitiligo in Saudis.

Molecular cloning and sequencing of a cDNA encoding rabbit presenilin-1 (Ps1) fragment was performed by reverse transcription polymerase chain reaction (RT-PCR) using primers: 5'-GGA TGA GCA GCT AAT CTA TAC C-3' and 5'-TCC ATT CAG GGA GGT ACT TGA TA-3'. The cDNA fragment revealed 402 nucleotides. The sequence was well conserved and found to be 91, 90, 88, 87 and 78% homologous to that of human, lemur, rat, mouse and chicken, respectively. The cDNA translated into a 130 amino-acid protein fragment. The deduced amino-acid sequence was also well conserved in various species and exhibited 98% similarities with those of rat, lemur and human homologues. However, differences were noticed at residues 145, 168 and 212. This cDNA fragment is quite significant because it is the most conserved portion of Ps1 in various animals and encodes four transmembrane regions (TM2, 3, 4, 5) as defined in human Ps1. Moreover, it includes more than 50% of the sites at which substitutions have been reported in familial Alzheimer's disease (FAD). Therefore, it is suggested that the rabbit can be used as an experimental model for future studies on Ps1 and its physiological functions to work out possible pathways leading to FAD linked neurodegeneration.

Background Methylenetetrahydrofolate reductase (MTHFR), a critical enzyme in folate metabolism is involved in DNA synthesis, DNA repair and DNA methylation. The functional polymorphism of MTHFR gene, C677T has been shown to impact various diseases and implicated as a risk factor for the development of various neurodegenerative disorders including glaucoma. Methods We investigated MTHFR C677T genotypes and alleles frequencies in primary glaucoma [primary open angle glaucoma (POAG) and primary angle closure glaucoma (PACG)] patients and matched healthy controls in a case-control study. Two hundred ten primary glaucoma cases were studied for MTHFR C677T polymorphism and compared with 280 controls taken from the healthy population, employing the polymerase chain reaction-restriction fragment length polymorphism technique (PCR-RFLP). The MTHFR gene was amplified using specific primers. The PCR products (294 bp) was subsequently digested with HinfI (New England Biolabs) at 37 °C for 12 h, separated by electrophoresis on 2 % agarose gels, and visualized with ethidium bromide staining. The restriction digestion yielded 168 and 126 bp fragments for TT, 294, 168 and 126 bp fragments for CT and undigested PCR product 294 bp indicating CC genotype. Results We found the frequency of the genotypes and alleles of MTHFR C677T differ significantly between cases and controls. The frequencies of allele T and genotype CT were significantly higher while the frequencies of allele C and genotype CC were lower in primary glaucoma patients as compared to controls (p