Israel Medical Association Journal

Background: Methotrexate is the most frequently administered first-line treatment for rheumatoid arthritis (RA). The disease-modifying effects of methotrexate are mainly associated with enhanced release of free adenosine. The downstream anti-inflammatory effects of adenosine are mediated via its binding to adenosine receptor 2A (ADORA2A) and 3 (ADORA3). Many clinically important single nucleotide polymorphisms (SNPs) were reported in ADORA2A and ADORA3 genes.

Objectives: To investigate whether tagging ADORA2A and ADORA3 polymorphisms influences methotrexate treatment in RA.

Methods: In total, 212 RA patients treated with methotrexate were genotyped for tagging ADORA2A (rs2298383, rs8141793, rs2236624, rs5751876, rs35320474, and rs17004921) and ADORA3 SNPs (rs2298191, rs1544223, rs78594984, rs35511654, rs2229155, rs3393, and rs3394).

Results: RA patients who carried ADORA3 rs35511654 G allele showed a tendency toward better response to methotrexate treatment (P = 0.054). Carriers of ADORA2A polymorphic allele rs2298383 (P = 0.011), rs2236624 (P = 0.027), rs5751876 (P = 0.018), and rs35320474 (P = 0.026) were less likely to experience methotrexate induced adverse events. All associations remained significant after adjustment for clinical factors. The effects of these polymorphisms were also significant in haplotype analyses.

Conclusions: Polymorphisms in the ADORA2A gene may influence methotrexate treatment response and may be considered as a potential biomarker for methotrexate treatment in rheumatoid arthritis.

Background: Diffuse large B-cell lymphoma (DLBCL) accounts for 30% of all non-Hodgkin lymphomas (NHL) and 80% of agressive lymphomas. Besides the traditional International Prognostic Index (IPI), some other factors may also influence the prognosis of DLBCL patients.

Objectives: To study how the genetic polymorphisms in the metabolic pathway influence the event-free and overall survivals and therapeutic responses in DLBCL.

Methods: The study was comprised of 51 patients (32 men, 19 women). The average age was 53.1 years. DLBCL was diagnosed between 2011 and 2016 and the average follow-up time was 3.78 years. These patients received 1–8 cycles (an average of 6.2 cycles) of rituximab, cyclophosphamide, doxorubicin, vincristin, prednisolon (R-CHOP) immunochemotherapy. Real-time polymerase chain reaction was used to determine the genetic polymorphisms of CYP2E1, GSTP1, NAT1, and NAT2 genes.

Results: Our results showed that the polymorphisms of CYP2E1, GSTP1, and NAT1 genes did not influence the prognosis of DLBCL patients significantly. In terms of the NAT2 gene, GG homozygous patients showed slightly better therapeutic response and survival results compared to those bearing an A allele; however, the differences were not statistically significant.

Conclusions: Our results could not confirm that genetic polymorphism in metabolic pathways has any predictive role in DLBCL. 

 

Vitamin D deficiency is becoming an increasing problem worldwide. It should not be underestimated, not only due to the well-known consequences vitamin D deficiency has on bone health, but primarily because recent studies have shown how the biologically active form of vitamin D – 1,25(OH)2D – is involved in many biological processes, including immune system modulation. Moreover, the presence of a vitamin D receptor was discovered in almost all immune cells and some of its polymorphisms were found to be associated with increased incidence of autoimmune diseases. This finding led to a proposed link between vitamin D deficiency and autoimmune diseases. Patients affected by various autoimmune diseases showed low levels of vitamin D. However, it is not always clear whether vitamin D deficiency is the cause or rather a consequence of the disease. Limitations of the studies, such as the small number of patients, heterogeneity of selected groups, environmental conditions, methods used to measure vitamin D serum concentration and other confounding factors do not lead to unequivocal results to demonstrate a direct link between low vitamin D levels and autoimmune disease. Therefore, randomized trials are needed to clarify conflicting results.

Background: Cancer is a leading cause of mortality worldwide. The most effective way to combat cancer is by prevention and early detection.

Objectives: To evaluate the outcome of screening an asymptomatic population for the presence of benign and neoplastic lesions.

Methods: Routine screening tests for prevention and/or early detection of 11 common cancers were conducted in 300 consecutive asymptomatic, apparently healthy adults, aged 25–77 years. Other tests were performed as indicated.

Results: Malignant and benign lesions were found in 3.3% and 5% of the screenees, respectively, compared to 1.7% in the general population. The most common lesions were in the gastrointestinal tract followed by skin, urogenital tract and breast. Advanced age and a family history of a malignancy were associated with increased risk for cancer with an odds ratio of 9 and 3.5, respectively (95% confidence interval 1.1–71 and 0.9–13, respectively). Moreover, high serum C-reactive protein levels and polymorphisms in the APC and CD24 genes indicated high cancer risk. When two of the polymorphisms existed in an individual, the risk for a malignant lesion was extremely high (23.1%; OR[1] 14, 95% CI[2] 2.5–78).

Conclusions: Screening asymptomatic subjects identifies a significant number of neoplastic lesions at an early stage. Incorporating data on genetic polymorphisms in the APC and CD24 genes can further identify individuals who are at increased risk for cancer. Cancer can be prevented and/or diagnosed at an early stage using the screening facilities of a multidisciplinary outpatient clinic.

Background: It has been argued that arginine replacement in locus16 (Arg16) of ß₂ adrenergic receptor with glycin (Gly16) increases asthma severity, while glutamin replacement in locus 27 (Gln27) with glutamic acid (Glu27) decreases it. In addition, ethnic dependency of these polymorphisms has been described, but few studies investigated its relation to asthma severity in a non-anglosaxic population.

Objectives: To investigate non-anglosaxic ethnic influences on ß₂AR[1] polymorphisms and its correlations to asthma severity.

Methods: Sixty-six Israeli Jewish and Arab asthmatics who had near-fatal asthma and/or severe nocturnal asthma and/or steroid-dependency were investigated for genetic polymorphisms of ß₂AR and compared to matched controls. The Jewish patients included both Ashkenazi (of East European origin) and non-Ashkenazi (originating from the Middle East or North Africa). The results were compared with those of ethnically matched 113 non-asthmatic Israelis, and of non-asthmatic Anglo-Saxons described in the literature.

Results: We found no significant genetic differences between the asthmatics and their controls or between the various ethnic groups of our population. However, the prevalence of Glu27 was significantly lower in non-asthmatic Israelis compared to non-asthmatic Anglo-Saxons.

Conclusions: The genetic distribution of ß₂AR polymorphisms in severe Israeli asthmatics is not different from that of non-asthmatic Israelis and therefore its clinical impact on asthma is probably minimal.

Background: The precise genes involved in conferring prostate cancer risk in sporadic and familial cases are not fully known.

Objectives: To evlauate the genetic profile within several candidate genes of unselected prostate cancer cases and to correlate this profile with disease parameters.

Methods: Jewish Israeli prostate cancer patients (n=224) were genotyped for polymorphisms within candidate genes: p53, ER, VDR, GSTT1, CYP1A1, GSTP1, GSTM1, EPHX and HPC2/ELAC2, followed by analysis of the genotype with relevant clinical and pathologic parameters.

Results: The EPHX gene His113 allele was detected in 21.4% (33/154) of patients in whom disease was diagnosed above 61 years, compared with 5.7% (4/70) in earlier onset disease (P < 0.001). Within the group of late-onset disease, the same allele was noted in 5.5% (2/36) with grade I tumors compared with 18% (34/188) with grade II and up (P = 0.004). All other tested polymorphisms were not associated with a distinct clinical or pathologic feature in a statistically significant manner.

Conclusions: In Israeli prostate cancer patients, the EPHX His113 allele is seemingly associated with a more advanced, late-onset disease. These preliminary data need to be confirmed by a larger and more ethnically diverse study.

Background: Gaucher disease results from the accumulation of glucosylceramide (glucocerebroside) in tissues of affected persons. Patients sharing the same genotype present with widely varying degrees of lipid storage and of clinical manifestations.

Objectives: To determine whether variation in the glucosylceramide synthase (UDPGlucose ceramide glucosyltransferase) gene, which encodes the enzyme that regulates the synthesis of glucocerebroside, could account for the variability and clinical manifestations.

Methods: Patients homozygous for the 1226G (N370S) mutation, the most common in the Ashkenazi Jewish population, were investigated. The exons and flanking sequences of the gene were sequenced using DNA derived from five very mild Gaucher disease patients and four patients with relatively severe Gaucher disease. Results: One polymorphism was found in the coding region, but this did not change any amino acids. Seven other polymorphisms were found in introns and in the 5' untranslated region. Some of these were single nucleotide polymorphisms; others were insertions. The mutations appear to be in linkage equilibrium and none were found with a significantly higher frequency in either severe or mildly affected individuals.

Conclusions: Mutations in the glucosylceramide synthase gene do not appear to count for the variability in expression of the common Jewish Gaucher disease mutation.
 

Background: Platelet adhesion and aggregation are mediated by specific platelet membrane glycoproteins GPIa/IIa, GPIba, and GPIIb/IIIa, and are essential steps in thrombus formation and development of acute myocardial infarction.

Objective: To evaluate the risks exerted by each of the following polymorphisms: HPA-1a/b in GPIIIa; 807C/T in GPIa; and HPA-2a/b, VNTR and Kozak C/T in GPIba in young males with AMI[1]..

Methods: We conducted a case-control study of 100 young males with first AMI before the age of 53 and 119 healthy controls of similar age. All subjects were tested for the above polymorphisms.

Results: The allele frequencies of each of the platelet polymorphism were not significantly different between the young men with AMI and the controls. Smoking alone was associated with a 9.97-fold risk, and the presence of at least one metabolic risk factor resulted in a 2.57-fold risk of AMI.

Conclusion: These results indicate that platelet glycoproteins polymorphisms are not an independent risk factor for AMI.

The complex genetic nature of many common diseases makes the identification of the genes that predispose to these ailments a difficult task. In this review we discuss the elements that contribute to the complexity of polygenic diseases and describe an experimental strategy for disease-related gene discovery that attempts to overcome these factors. This strategy involves a population-based case-control paradigm and makes use of a highly informative, homogeneous founder population, many of whose members presently reside in Israel. The properties of single nucleotide polymorphisms, which are presently the markers of choice, are discussed, and the technologies that are currently available for SNP[1] genotyping are briefly presented.

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[1] SNP = single nucleotide polymorphism