CD147 rs8259T>A Variant Confers Susceptibility to COVID-19 Infection within the Mexican Population

BACKGROUND

Coronavirus disease 2019 (COVID-19) is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Clinical manifestations of COVID-19 range from mild flu-like symptoms to severe respiratory failure. Nowadays, extracellular matrix metalloproteinase inducer (EMMPRIN), also known as cluster of differentiation 147 (CD147) or BASIGIN, has been studied as enabling viral entry and replication within host cells. However, the impact of the CD147 rs8259T>A single nucleotide variant (SNV) on SARS-CoV-2 susceptibility remains poorly investigated.

OBJECTIVE

To investigate the impact of rs8259T>A on the CD147 gene in individuals from Mexico with COVID-19 disease.

METHODS

We genotyped the CD147 rs8359T>A SNV in 195 patients with COVID-19 and 185 healthy controls from Mexico. In addition, we also measured the expression levels of CD147 and TNF mRNA and miR-492 from whole blood of patients with COVID-19 through RT-q-PCR.

RESULTS

We observed a significant association between the CD147 rs8259T>A SNV and susceptibility to COVID-19: T vs. A; OR 1.36, 95% CI 1.02-1.81; p = 0.037; and TT vs. AA; OR 1.77, 95% CI 1.01-3.09; p = 0.046. On the other hand, we did not find differences in CD147, TNF or miR-492 expression levels when considering the genotypes of the CD147 rs8259T>A SNV.

CONCLUSIONS

Our results suggest that the CD147 rs8259T>A variant is a risk factor for COVID-19.

Importance of the SARS-CoV-2 genome and spike protein in the immunopathogenesis of COVID-19 and in the efficacy of vaccines

Coronavirus (CoV) infections cause respiratory and enteric diseases with clinical manifestations ranging from faint to severe, even lead to death of patients. High connectivity between nations and infectivity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), represent a global health problem as the coronavirus disease 19 (COVID-19). This CoV-2 that cause SARS, which appeared in Wuhan, China, in December 2019 originated COVID-19 and declared as pandemic a few months posterior its appearance. In this review, the genomic and spike protein characteristics of SARS-CoV-2, the role of SARS-CoV-2 in the COVID-19 pathogenesis, cytokine storm, the role of cytotoxic T and B cells against SARS-CoV-2, as well as the vaccines efficacy (taking into account mutations in the spike protein) are described.

A Novel Technique for the Evaluation and Interpretation of Elastography in Salivary Gland Involvement in Primary Sjögren Syndrome

Ultrasound (US) of major salivary glands (MSG) evaluates echogenicity, border features and vascularization, with elastography, it can detect tissue elasticity and glandular fibrosis, related to inflammation in Primary Sjögren’s syndrome (pSS). This study aimed to develop a novel technique by pixel analysis for evaluation and interpretation of elastography in MSG in pSS. A cross-sectional and observational multicenter study was conducted. The US of MSG performed in orthogonal planes in grayscale, Doppler, and shear-wave elastography. For elastography images of each gland were analyzed with the open-source program ImageJ to perform a pixel analysis. Statistical analysis was performed with the IBM-SPSS v25 program. Fifty-nine women with a mean age of 57.69 (23–83) years were recruited; pSS mean duration of 87 (5–275) months, and 12 healthy women without sicca symptoms as a control group with a mean age of 50.67 (42–60) years. Intragroup analysis showed p-values >0.05 between sicca symptoms, ocular/dryness tests, biopsy, US, and pixel analysis; correlation between Hocevar and pixel analysis was not found (rho < 0.1, p >0.5). MSG anatomical size was 41.7 ± 28.2 mm vs. 67.6 ± 8.8 mm (p ≤ 0.0001); unstimulated whole saliva flow rate was 0.80 ± 0.80 ml/5 min vs. 1.85 ± 1.27 ml/5 min (p = 0.016). The elastography values (absolute number of pixels) were 572.38 ± 99.21 vs. 539.69 ± 93.12 (p = 0.290). A cut-off point risk for pSS identified with less than 54% of red pixels in the global MSG mass [OR of 3.8 95% CI (1.01–15.00)]. Pixel analysis is a new tool that could lead to a better understanding of the MSG chronic inflammatory process in pSS.

BLK and BANK1 variants and interactions are associated with susceptibility for primary Sjögren's syndrome and with some clinical features

BLK and BANK1 in primary Sjögren's syndrome (pSS) have scarcely been evaluated and the results are inconclusive. The aim of our study was to determine whether single nucleotide variants (SNVs) located within BLK or BANK1 are associated with susceptibility, clinical and serological features, and smoking in pSS. BLK rs13277113A/G, BANK1 rs10516487G/A and rs3733197G/A were genotyped in 203 cases and 424 controls using a TaqMan® SNP genotyping assay. The BLK rs13277113A allele showed association with pSS under the allelic (OR 1.35, p = 0.02), and recessive (OR 1.83, p = 0.003) model, while, BANK1 rs3733197G/A showed association under the dominant model (OR 2.90, p = 0.043). Interactions between BANK1 and BLK genotypes also showed association (OR 2.36, p < 0.0001). In addition, BLK rs13277113A/G was associated with protection against arthritis and BANK1 rs10516487G/A with both arthritis and keratoconjunctivitis sicca, meanwhile, BANK1 rs3733197G/A was associated with smoking in patients with pSS. This is the first study to describe an association between BLK and susceptibility to pSS in a Latin-American population. Our data also shows a first evidence of association between interactions of BLK and BANK1 in pSS, and association of BLK and BANK1with arthritis, keratoconjunctivitis sicca and smoking in patients with pSS.

Genotype-Environment Interaction Analysis of NQO1, CYP2E1, and NAT2 Polymorphisms and the Risk of Childhood Acute Lymphoblastic Leukemia: A Report From the Mexican Interinstitutional Group for the Identification of the Causes of Childhood Leukemia

Background: Acute lymphoblastic leukemia (ALL) is the main type of cancer in children. In Mexico and other Hispanic populations, the incidence of this neoplasm is one of the highest reported worldwide. Functional polymorphisms of various enzymes involved in the metabolism of xenobiotics have been associated with an increased risk of developing ALL, and the risk is different by ethnicity. The aims of the present study were to identify whether NQO1, CYP2E1, and NAT2 polymorphisms or some genotype-environmental interactions were associated with ALL risk in Mexican children.

Methods: We conducted a case-control study including 478 pediatric patients diagnosed with ALL and 284 controls (children without leukemia). Ancestry composition of a subset of cases and controls was assessed using 32 ancestry informative markers. Genetic-environmental interactions for the exposure to hydrocarbons were assessed by logistic regression analysis.

Results: The polymorphisms rs1801280 (OR 1.54, 95% CI 1.21–1.93), rs1799929 (OR 1.96, 95% CI 1.55–2.49), and rs1208 (OR 1.44, 95% CI 1.14–1.81) were found to increase the risk of ALL; being the risks higher under a recessive model (OR 2.20, 95% CI 1.30–1.71, OR 3.87, 95% CI 2.20–6.80, and OR 2.26, 95% CI 1.32–3.87, respectively). Gene-environment interaction analysis showed that NAT2 rs1799929 TT genotype confers high risk to ALL under exposure to fertilizers, insecticides, hydrocarbon derivatives, and parental tobacco smoking. No associations among NQO1, CYP2E1, and ALL were observed.

Conclusion: Our study provides evidence for the association between NAT2 polymorphisms/gene-environment interactions, and the risk of childhood ALL in Mexican children.

Role of genetic variability in Mendelian and multifactorial diseases

The first draft of the human genome sequencing published in 2001 reported a large number of single nucleotide polymorphisms (SNPs). Given that these polymorphisms could practically represent all the variability involved in the susceptibility, protection, severity, among other aspects, of various common diseases, as well as in their response to medications, it was thought that they might be "the biomarkers of choice" in personalized genomic medicine. With the new information obtained from the sequencing of a larger number of genomes, we have understood that SNPs are only an important part of the genetic markers involved in these traits. In addition to SNPs, other variants have been identified, such as insertions/deletions (INDELs) and copy number variants (CNVs), which - in addition to classic variable number tandem repeats (VNTRs) and short tandem repeats (STRs) - originate or contribute to the development of diseases. The use of these markers has served to identify regions of the genome involved in Mendelian diseases (one gene-one disease) or genes directly associated with multifactorial diseases. This review has the purpose to describe the role of STRs, VNTRs, SNPs, CNVs and INDELs in linkage and association studies and their role in Mendelian and multifactorial diseases.

Papel de la variabilidad genética en las enfermedades mendelianas y multifactoriales

The first draft of the human genome sequencing published in 2001 reported a large number of single nucleotide polymorphisms (SNPs). Given that these polymorphisms could practically represent all the variability involved in the susceptibility, protection, severity, among other aspects, of various common diseases, as well as in their response to medications, it was thought that they might be "the biomarkers of choice" in personalized genomic medicine. With the new information obtained from the sequencing of a larger number of genomes, we have understood that SNPs are only an important part of the genetic markers involved in these traits. In addition to SNPs, other variants have been identified, such as insertions/deletions (INDELs) and copy number variants (CNVs), which - in addition to classic variable number tandem repeats (VNTRs) and short tandem repeats (STRs) - originate or contribute to the development of diseases. The use of these markers has served to identify regions of the genome involved in Mendelian diseases (one gene-one disease) or genes directly associated with multifactorial diseases. This review has the purpose to describe the role of STRs, VNTRs, SNPs, CNVs and INDELs in linkage and association studies and their role in Mendelian and multifactorial diseases.

[MicroRNA en enfermedades autoinmunes]

Los microRNA (miRNA) son pequeños RNA no codificantes de aproximadamente 17 a 24 nucleótidos de longitud, los cuales se unen complementaria y principalmente en las regiones 3' UTR (región no traducida) de diversos RNA mensajeros (mRNA, messenger RNA). Su función general es regular negativamente la expresión génica a nivel postranscripcional, inhibiendo la traducción. Perfiles de expresión de miRNA alterados han sido identificados en diferentes líquidos, células y tejidos humanos afectados con diversas enfermedades autoinmunes y algunos se han propuestos potencialmente como biomarcadores de diagnóstico, pronóstico, actividad, etcétera, en estas patologías. Adicionalmente, variantes comunes del genoma humano, denominados polimorfismos de un solo nucleótido (SNP, single nucleotide polymorphisms) localizados en genes de miRNA han sido asociados con susceptibilidad, gravedad, y actividad en estas enfermedades. El objetivo de esta revisión es describir la biogénesis de los miRNA, su función, así como los perfiles de expresión y SNP en genes de miRNA asociados con diversas enfermedades autoinmunes, incluyendo tiroiditis autoinmune (tiroiditis de Hashimoto y enfermedad de Graves), lupus eritematoso sistémico, artritis reumatoide y síndrome de Sjögren primario.

Tumor necrosis factor (TNF) and TNFR1 polymorphisms are not risk factors for rheumatoid arthritis in a Mexican population

Tumor necrosis factor (TNF) plays an important role in the pathogenesis of rheumatoid arthritis (RA). Different genetic variants including the TNF -308G/A polymorphism are associated with RA susceptibility. However, these findings have not been replicated in all populations. The aim of this study was to determine whether the TNF -1031T/C (rs1799964), -376G/A (rs1800750), -308G/A (rs1800629) -238G/A (rs361525), and TNFR1 -609G/T polymorphisms are associated with RA susceptibility in a sample of Mexican patients. Our study included 499 patients with RA and 492 healthy controls. The genotypes of the TNF polymorphisms were obtained using TaqMan assay. The genotype and allele frequencies of the TNF -1031T/C, -376G/A, -308G/A, -238G/A, and TNFR1 -609G/T polymorphisms were similar among RA cases versus healthy controls, and no association with RA susceptibility was identified. Our results suggest that the TNF -1031T/C, -376G/A, -308G/A, -238G/A, and TNFR1 -609G/T polymorphisms are not associated with RA susceptibility in a sample of Mexican patients.

Gene Expression Profiling of Acute Lymphoblastic Leukemia in Children with Very Early Relapse

BACKGROUND AND AIMS

Acute lymphoblastic leukemia (ALL) is the most common childhood cancer worldwide. Mexican patients have high mortality rates, low frequency of good prognosis biomarkers (i.e., ETV6-RUNX1) and a high proportion is classified at the time of diagnosis with a high risk to relapse according to clinical features. In addition, very early relapses are more frequently observed than in other populations. The aim of the study was to identify new potential biomarkers associated with very early relapse in Mexican ALL children through transcriptome analysis.

METHODS

Microarray gene expression profiling on bone marrow samples of 54 pediatric ALL patients, collected at time of diagnosis and/or at relapse, was performed. Eleven patients presented relapse within the first 18 months after diagnosis. Affymetrix Human Transcriptome Array 2.0 (HTA 2.0) was used to perform gene expression analysis. Annotation and functional enrichment analyses were carried out using Gene Ontology, KEGG pathway analysis and Ingenuity Pathway Analysis tools.

RESULTS

BLVRB, ZCCHC7, PAX5, EBF1, TMOD1 and BLNK were differentially expressed (fold-change >2.0 and p value <0.01) between relapsed and non-relapsed patients. Functional analysis of abnormally expressed genes revealed their important role in cellular processes related to the development of hematological diseases, cancer, cell death and survival and in cell-to-cell signaling interaction.

CONCLUSIONS

Our data support previous findings showing the relevance of PAX5, EBF1 and ZCCHC7 as potential biomarkers to identify a subgroup of ALL children in high risk to relapse.

Analysis of Thiopurine S-Methyltransferase Deficient Alleles in Acute Lymphoblastic Leukemia Patients in Mexican Patients

BACKGROUND AND AIMS

It has been demonstrated that heterozygote and homozygote thiopurine S-methyltransferase (TPMT) mutant allele carriers are at high risk to develop severe and potentially fatal hematopoietic toxicity after treatment with standard doses of 6-mercaptopurine (6-MP) and methotrexate (MX). Those drugs are the backbone of acute lymphoblastic leukemia (ALL) and several autoimmune disease treatments. We undertook this study to determine the frequency of the TPMT deficient alleles in children with ALL and non-ALL subjects from Mexico City and Yucatan, Mexico.

METHODS

We included 849 unrelated subjects, of which 368 ALL children and 342 non-ALL subjects were from Mexico City, and 60 ALL cases and 79 non-ALL individuals were from Yucatan. Genotyping of the rs1800462, rs1800460 and rs1142345 SNPs was performed by 5'exonuclease technique using TaqMan probes (Life Technologies Foster City, CA).

RESULTS

The mutant TPMT alleles were present in 4.8% (81/1698 chromosomes) and only 0.2% were homozygote TPMT*3A/TPMT*3A. We did not find statistically significant differences in the distribution of the mutant alleles between patients from Mexico City and Yucatan in either ALL cases or non-ALL. Nonetheless, the TPMT*3C frequency in ALL patients was higher than non-ALL subjects (p = 0.03). To note, the null homozygous TPMT*3A/TPMT*3A genotype was found in 2.5% of the non-ALL subjects.

CONCLUSIONS

TPMT mutant alleles did not exhibit differential distribution between both evaluated populations; however, TPMT*3C is overrepresented in ALL cases in comparison with non-ALL group. Assessing the TPMT mutant alleles could benefit the ALL children and those undergoing 6-MP and MX treatment.

[Functional implications of single nucleotide polymorphisms (SNPs) in protein-coding and non-coding RNA genes in multifactorial diseases]

Single nucleotide polymorphisms (SNPs) represent the most common type of variation in the human genome. The SNPs located in protein-coding and non-coding RNA genes are classified as neutral and functional. The neutral have no effect, while the functional affect different biological processes and continually confer risk for multifactorial diseases. Functional SNPs found in the promoters of protein-coding and non-coding RNA genes (microRNAs: miRNAs) termed regulatory SNP (rSNPs) and miRNAs rSNPs (miR-rSNPs), respectively, affect the gene expression. Functional SNPs located on the structure of the precursor mRNAs (exons and introns), mature mRNA (5´ untranslated region [UTR], coding sequence, and 3´ UTR), and primary, precursor, and mature miRNAs are termed structural RNA SNPs (srSNPs) and miR-srSNPs, respectively. The srSNPs affect the splicing (and alternative splicing), srSNPs affect the splicing (and alternative splicing), the translation, stability, amino acid sequence, structure, and function of proteins and interaction between mRNA/miRNAs. Finally, the miR-srSNPs affect the structure, processing and interaction between miRNAs/mRNAs. Functional characterization of potentially harmful risk alleles of the SNPs located in protein-coding and non-coding RNA genes have contributed to an understanding of their functions in the complex diseases. The objective of this review is update the reader on the functional role of the SNPs located in protein-coding and non-coding RNA genes and their relationship with multifactorial diseases.

[Genetics and genomics in rheumatoid arthritis (RA): An update]

Rheumatoid arthritis is a chronic inflammatory autoimmune disease that affects approximately 0.5-1% of the general population and leads to chronic synovial inflammation, destruction of cartilage and bone, and disability. The heritability of rheumatoid arthritis has been estimated to be about 60%, while the contribution of HLA to heritability has been estimated to be 11-37%. Other genes, such as PTPN22, STAT4, CTLA4, TRAF1, PADI4, IRF5, FCRL3, TNFIP3, TNF-α, miRNAs, CD28, CD40, TYK2, etc., have been associated with susceptibility, severity, activity, and treatment response of rheumatoid arthritis. The aim of this review is to describe the role of gene variants located in immune system genes associated with susceptibility to rheumatoid arthritis.

Skeletal manifestations of Marfan syndrome associated to heterozygous R2726W FBN1 variant: sibling case report and literature review

Background

FBN1 (15q21.1) encodes fibrillin-1, a large glycoprotein which is a major component of microfibrils that are widely distributed in structural elements of elastic and non-elastic tissues. FBN1 variants are responsible for the related connective tissue disorders, grouped under the generic term of type-1 fibrillinopathies, which include Marfan syndrome (MFS), MASS syndrome (Mitral valve prolapse, Aortic enlargement, Skin and Skeletal findings, Acromicric dysplasia, Familial ectopia lentis, Geleophysic dysplasia 2, Stiff skin syndrome, and dominant Weill-Marchesani syndrome.

Case presentation

Two siblings presented with isolated skeletal manifestations of MFS, including severe pectus excavatum, elongated face, scoliosis in one case, and absence of other clinical features according to Ghent criteria diagnosis, were screened for detection of variants in whole FBN1 gene (65 exons). Both individuals were heterozygous for the R2726W variant. This variant has been previously reported in association with some skeletal features of Marfan syndrome in the absence of both tall stature and non-skeletal features. These features are consistent with the presentation of the siblings reported here.

Conclusion

The presented cases confirm that the R2726W FBN1 variant is associated with skeletal features of MFS in the absence of cardiac or ocular findings. These findings confirm that FBN1 variants are associated with a broad phenotypic spectrum and the value of sequencing in atypical cases.

[Single nucleotide polymorphisms (SNPs): functional implications of regulatory-SNP (rSNP) and structural RNA (srSNPs) in complex diseases]

Single nucleotide polymorphisms (SNPs) represent to the genetics variant most common founded in the human genome. These polymorphisms have a wide distribution and can found in any region of gene or mRNA, the SNPs that have functional implications on the levels of gene expression are called regulatory SNPs (rSNPs), while those that affect translation, splicing, efficiency to enhance or inhibit the alternative, mRNA stability and protein function (without altering its structure), they are called structural RNA SNPs (srSNPs). Several studies have identified to these polymorphisms associated with different common diseases e.g. hypertension, obesity, rheumatoid arthritis and coronary artery disease. The aim of this review is to discuss the functional implication of rSNPs and srSNPs in the common diseases.

No association between catechol-o-methyltransferase Val108/158Met polymorphism and schizophrenia or its clinical symptomatology in a Mexican population

The gene coding for catecol-o-methyltransferase (COMT), participant in the metabolism of catecholamines, has long been implicated as a candidate gene for schizophrenia. We determined the relation of the COMT Val108/158Met polymorphism with schizophrenia or its symptomatology (negative, disorganized and psychotic dimension). We conducted a case–control study comprising 186 patients with schizophrenia and 247 controls. The diagnosis of schizophrenia was established using the DSM-IV criteria for this illness. The clinical symptomatology was assessed through the Scale for the Assessment of Negative Symptoms and the Scale for the Assessment of Positive Symptoms. No significant differences were found in the distribution of alleles (χ2 = 0.01, df = 1, p = 0.90) or genotypes (χ2 = 1.66, df = 2, p = 0.43) between schizophrenic patients and the control group. Multivariate analysis showed that the COMT Val108/158Met polymorphism has no influence in the clinical symptomatology of schizophrenia. Our results showed no association between COMT Val108/158Met and schizophrenia or evidence for an association between COMT and the clinical symptomatology of this illness. This suggests that the COMT gene may not contribute to the risk for schizophrenia among the Mexican population.

Juvenile rheumatoid arthritis and asthma, but not childhood-onset systemic lupus erythematosus are associated with FCRL3 polymorphisms in Mexicans

A regulatory single nucleotide polymorphism located in the 5' region (-169T/C) of the Fc receptor-like 3 (FCRL3_3) gene has been associated with both susceptibility and protection in immune diseases. This case-control study aimed to evaluate the association between FCRL3 polymorphisms and juvenile rheumatoid arthritis (JRA), asthma, and childhood-onset systemic lupus erythematosus (SLE) in a Mexican population. We performed PCR-based genotyping to identify four FCRL3 single nucleotide polymorphisms (FCRL3_3 to FCRL3_6) in patients with JRA (n=202), asthma (n=239), or childhood-onset SLE (n=377), and healthy controls (n=400). The case-control analysis showed a male-gender dependent association between the FCRL3_3C, FCRL3_5C, and FCRL3_6A alleles and either JRA (OR=0.57, p=0.003; OR=0.55, p=0.002; OR=0.53, p=0.0007, respectively) or asthma (OR=0.72, p=0.04; OR=0.74, p=0.05; OR=0.70, p=0.02, respectively). As expected, minor alleles of these SNPs with the CGCA haplotype were also significantly associated with JRA (OR=0.35, p=0.00005) and asthma (OR=0.61, p=0.007). We found no association between FCRL3 SNPs or haplotypes and childhood-onset SLE. These results supported the notion that FCRL3 is involved in the etiology of several immune diseases. Our results also suggested that SNPs located in the FCRL3 gene were protective against JRA and asthma in male Mexican patients.

Distribution of the IL-1RN, IL-6, IL-10, INF-γ, and TNF-α Gene Polymorphisms in the Mexican Population

BACKGROUND

Cytokines are a group of polypeptides with an important role in the inflammatory response. It has been suggested that certain polymorphisms located in several cytokine genes are associated with different diseases. The aim of the present study was to establish the gene frequency of 13 polymorphisms of the IL-1RN, IL-6, IL-10, INF-γ, and TNF-α genes in a Mexican population. These polymorphisms have been reported in several populations, with important variation in frequency according to the studied population.

METHODS

Thirteen polymorphisms (rs419598, rs315951, rs2234663, rs3811058, rs1800796, rs2069827, rs1800896, rs1800871, rs1800872, rs1800629, rs2069709, rs2069710, and rs361525) were analyzed by 5' exonuclease TaqMan genotyping assays in a group of 248 healthy unrelated Mexican individuals.

RESULTS

The results obtained showed that the studied Mexican population presents significant differences (p<0.05) in the distribution of the IL1RN (rs419598, rs315951, and and rs2234663), IL1F10 (rs3811058), IL6 (rs1800796, rs2069827), IL10 (rs1800896, rs1800871, and rs1800872), and TNF-α (rs1800629) polymorphisms when compared to Caucasian, Asian, and African populations.

CONCLUSIONS

In summary, the distribution of the IL-1RN, IL-6, IL-10, and TNF-α cytokine gene polymorphisms distinguishes the studied Mexican population from other groups. Since the alleles of these cytokines are associated with the development of several inflammatory diseases, knowledge of the distribution of these alleles in the studied Mexican population could be helpful to understand their true role as a genetic susceptibility marker in this population.

[Systemic lupus erythematosus: genomics of the disease]

Systemic lupus erythematosus (SLE) is the prototype of autoimmune diseases with multiple autoantigens as targets,resulting in damage to many organs of the body. The disease is more common in females (> 90%) and around 15% of the cases present during childhood.Systemic lupus erythematosus is a complex disease in which both genetic (susceptibility/protection alleles) and environmental factors (infections, drugs, stress, etc.) contribute to its development.The current knowledge on genetic factors involved in SLE is based on the results of linkage analyses in multi-case families as well as from case-control or family-based genetic association studies. These types of genetic analyses have contributed to identifying susceptibility genes and constitute the first step towards understanding the molecular mechanisms underlying SLE.The aim of this review is to provide a current picture of the genes identified as susceptibility factors for SLE, and to highlight the ones described in the Mexican population.

[Genetic and genomic studies in the hypertension: an actualization of the genomic studies]

The arterial hypertension is considered to be the main risk factor for myocardial infarction, heart failure, ventricular arrhythmias, kidney failure, blindness and other diseases. Arterial hypertension is a multifactorial disease derived from environmental, genetic, gender and ethnic factors. In recent years, the World Health Organization estimated that approximately 17.5 million of deaths were due to cardiovascular diseases worldwide and that this pathology will become the leading cause of death in the next decade. Data from the National Survey of Mexican Ministry of Health (2006), reported approximately 17 million hypertensive adults, equivalent to a prevalence of 30.8% among Mexican population. As a consequence, hypertension represents the leading cause of morbidity from 2000 to 2005 and is increasing in recent years. However, studies have failed to clearly identify the molecular and genetic mechanisms of this pathology so far. Nevertheless, using the new technologies for analysis of variants in the genome, several genes in different loci that confer susceptibility to develop hypertension have been identified. In this review we compared the different studies in genetics and genomics of the hypertension that have been made worldwide and in Mexico, with the aim of identifying important genes involved in susceptibility to the development of this pathology.

[Pro-inflammatory and anti-inflammatory markers in coronary artery disease and acute ischemic coronary syndrome]

Inflammation plays an important role in the development of atherosclerotic lesions, affecting several stages of the atheroma's development going from the initial leukocyte recruitment to the eventual rupture of the unstable atherosclerotic plaque. The inflammatory reactions within coronary atherosclerotic plaques influence the clinical outcome of acute coronary syndromes and coronary artery disease. Recent studies suggest that inflammation markers may reflect different aspects of the atherothrombotic process in relation to the stages of acute coronary syndrome. These markers play an important role in the risk of developing coronary artery disease, and may correlate with its severity. Some cytokines, acute phase proteins, acute phase reactants proteins, and adhesion molecules released from the inflammatory cells may reflect the inflammatory process in atherosclerotic plaques. However, it remains to be determined whether these pro- and anti-inflammation markers may confer risk or protection for cardiovascular disease, or simply reflect the underlying disease process. The analysis of the markers may be useful for the development of new strategies for coronary disease prevention and treatment. Therefore, we need a well-designed evaluation of these markers before their use in the clinical practice.

BCR-ABL, ETV6-RUNX1 and E2A-PBX1: prevalence of the most common acute lymphoblastic leukemia fusion genes in Mexican patients

This study was conducted to determine the frequency of the most common fusion genes in Mexican pediatric patients with acute lymphoblastic leukemia (ALL). Molecular analysis using RT-PCR was carried out in 53-blood samples: 52 patients with de novo ALL and one with relapsed ALL. The ETV6-RUNX1 fusion was found in 7 cases (13.5%), BCR-ABL fusion was detected in 2 cases (3.8%), and 6 patients (11.5%) expressed the chimeric gene E2A-PBX1. The prevalence of E2A-PBX1 is one of the highest that has been described thus far in childhood ALL. Furthermore, we detected both the BCR-ABL, and E2A-PBX1 fusion in the relapsed patient. With regards to the immunophenotype, ETV6-RUNX1 was expressed in both pre-B and T-cell cases, while the presence of E2A-PBX1 and BCR-ABL was associated with the pre-B ALL phenotype. The prevalence of E2A-PBX1 in Mexican pediatric cases supports the existence of ethnic differences in the frequency of molecular markers of ALL.

Spectrum of RB1 gene mutations and loss of heterozygosity in Mexican patients with retinoblastoma: identification of six novel mutations

RB1 mutation detection has greatly improved the clinical management of retinoblastoma and provides critical information to predict the risk of inheriting the disease. We screened for RB1 gene sequence alterations in both peripheral blood and tumor specimens from a total of 48 Mexican retinoblastoma patients using an SSCP-based screening approach followed by sequencing. Overall, 21 (43.8%) cases were bilateral and 27 (56.2%) were unilateral. Interestingly, 51.8% of unilateral patients developed the tumor before age 1 year and 10 of which (71.4%) were diagnosed before the age of 6 months. Thirteen different oncogenic mutations were detected in 14/48 (29.2%) patients, 9 of which were germline (64.3%). Six of these mutations are novel (IVS3-1G>T, 125X, 389X, 610X, 750X and -149G>T). The most frequent types of mutation were frameshift and nonsense (30.8% each). Moreover, 5 intronic variants were identified, two of which are novel (g.41908 C/A and g.161976del6T). Loss of heterozygosity of the RB1 gene as assessed by intron1/BamHI and intron17/XbaI intragenic markers was 50.0% (18 of 36 informative cases), being higher in tumors with known mutations (76.9% vs 34.8%). This low mutation detection rate and the earlier age at diagnosis in unilateral retinoblastoma cases suggest that other RB1 inactivating mechanisms could be present in the retinoblastoma development. In this study, mutation analysis was not helpful to distinguish sporadic and hereditary retinoblastoma, so, other approaches are needed to improve the molecular diagnosis of retinoblastoma and supports further investigations of Mexican retinoblastoma patients.