High Prevalence of Familial Hypercholesterolemia Due to the Founder Effect of the LDLR c.2271del Variant in Communities of Oaxaca, Mexico.

INTRODUCTION: In Mexico, familial hypercholesterolemia (FH) is underdiagnosed, but population screening in small communities where at least one homozygous patient has already been detected results in a useful and inexpensive approach to reduce this problem. Considering that we previously reported nine homozygous cases from the state of Oaxaca, we decided to perform a population screening to identify patients with FH and to describe both their biochemical and genetic characteristics. METHODS: LDL cholesterol (LDLc) was quantified in 2,093 individuals from 11 communities in Oaxaca; either adults with LDLc levels ≥170 mg/dL or children with LDLc ≥130 mg/dL were classified as suggestive of FH and therefore included in the genetic study. LDLR and APOB (547bp fragment of exon 26) genes were screened by sequencing and MLPA analysis. RESULTS: Two hundred and five individuals had suggestive FH, with a mean LDLc of 223 ± 54 mg/dL (range: 131-383 mg/dL). Two pathogenic variants in the LDLR gene were detected in 149 individuals: c.-139_-130del (n = 1) and c.2271del (n = 148). All patients had a heterozygous genotype. With the cascade screening of their relatives (n = 177), 15 heterozygous individuals for the c.2271del variant were identified, presenting a mean LDLc of 133 ± 35 mg/dL (range: 60-168 mg/dL). CONCLUSIONS: The FH frequency in this study was 7.8% (164/2093), the highest reported worldwide. A founder effect combined with inbreeding could be responsible for the high percentage of patients with the LDLR c.2271del variant (99.4%), which allowed us to detect both significant biochemical heterogeneity and incomplete penetrance; hence, we assumed the presence of phenotype-modifying variants.

A novel approach for direct detection of the IGH::CRLF2 gene fusion by fluorescent in situ hybridization.

BACKGROUND: High expression of the Cytokine Receptor-Like Factor 2 (CRLF2) gene has been observed in patients with acute lymphoblastic leukemia BCR-ABL1-like subtype. Currently, there is no commercial system available for the direct detection of the IGH::CRLF2 fusion by fluorescent in situ hybridization (FISH), as there are for many other leukemia-related gene fusions. In an effort to verify the IGH::CRLF2 fusion, some researchers prepare home-grown FISH probes from bacterial artificial chromosome clones flanking the IGH and CRLF2 genes, which is the best alternative to confirm the fusion, however difficult to reproduce in most cytogenetic laboratories. RESULTS: For the direct observation of the IGH::CRLF2 gene fusion we designed a methodological approach requiring the two commercially available IGH and CRLF2 break-apart probes. CONCLUSIONS: Our methodological approach allows direct visualization of the IGH::CRLF2 gene fusion and has the potential to be used for identification of other gene fusions.

Effect of APOB gene polymorphisms on body mass index, blood pressure, and total cholesterol levels: A cross-sectional study in Mexican population.

APOB gene polymorphisms are considered risk factors for the development of dyslipidemia, hypertension, and cardiovascular disease (CVD) in several populations. In Mexico, these pathologies are frequent and studies regarding this gene are scarce. The aim of this cross-sectional study was to determined genotype, allele, and haplotype frequencies of APOB polymorphisms and performed analyses of association among the biochemical, hemodynamic, anthropometrical, and genetic variables. Blood samples were taken from 361 subjects from unselected Mexican population for biochemical analysis and for deoxyribonucleic acid extraction; besides blood pressure and body mass index (BMI) were measured. APOB polymorphisms rs934197, rs533617, rs693, and rs1042031 were genotyped by polymerase chain reaction (PCR)-restriction fragment length polymorphism; whereas, rs17240441 and c.66_67insCTGCTG were genotyped by PCR followed by electrophoresis. Genotype and allele frequencies were obtained by simple counting and deviations from Hardy-Weinberg equilibrium (HWE) were calculated by chi-square test. The effect of the polymorphisms on the quantitative variables was determined using analysis of variance, Student's t test, Pearson's and Spearman's correlations and multiple linear regression models. All the polymorphisms were within HWE. Frequencies of mutated alleles were highly heterogeneous: rs934197-T 33.6%, rs17240441-D 39.3%, c.66_67insCTGCTG-I 3.9%, rs533617-G 0.9%, rs693-T 40.5%, and rs1042031-G 17.3%. Chronic degenerative diseases were frequent in the studied population: overweight-obesity 55.1%, dyslipidemia 45.8%, and hypertension 23.5%. The association analyses showed that despite adjustments for age and sex the mutated alleles rs934197-T, rs1042031G, c.66_67-insCTGCTG-I, and rs533617-G, were related to lower values of BMI, total cholesterol (TC), systolic blood pressure, and diastolic blood pressure, respectively. All polymorphisms analyzed except rs533517 and c.66_67insCTGCTG showed high frequencies of the mutated allele, making them useful for association studies. Our results revealed that, APOB gene polymorphisms could be contributing to the development of several chronic diseases, such as essential hypertension, dyslipidemias, obesity, among others. However, specific studies with each pathology are needed to know the possible implications of the polymorphisms.

E6/E7 from Beta-2-HPVs 122, 38b, and 107 possess transforming properties in a fibroblast model in vitro.

Beta-2 Human papillomaviruses 38b, 107, and 122 have been frequently found in cervical cancer samples in western Mexico. Because their E6/E7 genes functions are not fully elucidated, we deepen into their transformation capabilities. To achieve this goal, primary human fibroblasts (FB) were transduced with E6/E7 genotype-specific viral particles. Additionally, E6/E7 from HPVs 16 and 18 were included as controls. All E6/E7-cell models increased their lifespan; however, it is important to highlight that FB-E6/E7-122 showed growth as accelerated as FB-E6/E7-16 and 18. Furthermore, both FB-E6/E7-38b and 122 exhibited abilities to migrate, and FB-E6/E7-122 presented high invasive capacity. On the other hand, ΔNp73 expression was found in all cell models, except for FB-pLVX (empty-vector). Finally, RNAseq found differentially expressed genes enriched in signaling pathways related to cell cycle, epithelial-mesenchymal transition, and cancer, among others. This study shows for the first time, the great transformative potential that genotypes of the Beta-2 also possess, especially HPV122. These Beta-2 HPVs can modulate some of the genes that are well known to be regulated by Alpha-HPVs, however, they also possess alternative strategies to modulate diverse signaling pathways. These data support the idea that Beta-2 HPVs should play an important role in co-infections with Alpha-HPV during carcinogenesis.

Biochemical, Clinical, and Genetic Characteristics of Mexican Patients with Primary Hypertriglyceridemia, Including the First Case of Hyperchylomicronemia Syndrome Due to GPIHBP1 Deficiency.

Primary hypertriglyceridemia (PHTG) is characterized by a high concentration of triglycerides (TG); it is divided between familial hyperchylomicronemia syndrome and multifactorial chylomicronemia syndrome. In Mexico, hypertriglyceridemia constitutes a health problem in which the genetic bases have been scarcely explored; therefore, our objective was to describe biochemical-clinical characteristics and variants in the APOA5, GPIHBP1, LMF1, and LPL genes in patients with primary hypertriglyceridemia. Thirty DNA fragments were analyzed using PCR and Sanger sequencing in 58 unrelated patients. The patients' main clinical-biochemical features were hypoalphalipoproteinemia (77.6%), pancreatitis (18.1%), and a TG median value of 773.9 mg/dL. A total of 74 variants were found (10 in APOA5, 16 in GPIHBP1, 34 in LMF1, and 14 in LPL), of which 15 could be involved in the development of PHTG: 3 common variants with significative odds and 12 heterozygous rare pathogenic variants distributed in 12 patients. We report on the first Mexican patient with hyperchylomicronemia syndrome due to GPIHBP1 deficiency caused by three variants: p.R145*, p.A154_G155insK, and p.A154Rfs*152. Moreover, eleven patients were heterozygous for the rare variants described as causing PHTG and also presented common variants of risk, which could partially explain their phenotype. In terms of findings, two novel genetic variants, c.-40_-22del LMF1 and p.G242Dfs*10 LPL, were identified.

Biased Clonal Evolution in Acute Promyelocytic Leukemia through Imbalances Affecting the der(17) but Not the der(15) Chromosome: Report of Two Cases.

Acute promyelocytic leukemia (APL) is characterized by the chromosomal translocation t(15;17)(q24;q21), raising two hybrid genes: PML::RARA and RARA::PML. There is a biased clonal evolution in APL since imbalances affecting the der(15) chromosome (the one that carries the transforming PML::RARA gene) have never been reported; instead, imbalances of the der(17), mainly in form of an ider(17)(q10), have been repeatedly documented. We here present two cases with APL who acquired an ider(17)(q10) as a secondary chromosomal change. The presence of the ider(17)(q10) implies several genomic consequences with potential to fuel tumor progression: (1) a duplication of the hybrid gene RARA::PML; (2) a cumulative haploinsufficiency for tumor suppressor genes located in the 17p arm; and (3) a cumulative triplosensitivity of genes located in 17q10→RARA::PML→15qter. Both our patients were treated following the PETHEMA LPA 2012 protocol with ATRA plus idarubicin and they have had a long event-free survival.

Molecular and Hematological Analysis of Alpha- and Beta-Thalassemia in a Cohort of Mexican Patients.

Introduction: Alpha- and beta-thalassemia are caused by reduced or absent synthesis of hemoglobin (Hb) subunits α and/or ß. HBA2, HBA1, and HBB mutations are the main cause of thalassemias. The aim of this article is to analyze molecular and hematological features of α- and ß-thal in a cohort of Mexican patients. Methods: One hundred forty-one thalassemia patients were studied. Peripheral blood was collected for blood cell count, electrophoresis, Hb quantification, and molecular testing. Molecular screening was performed by Gap-PCR, ARMS-PCR, Sanger sequencing, and MLPA. Results: Fifty-four patients had α-thal, 75 ß-thal, and 12 patients were complex cases, we observed 13 α- and 18 ß-thal alleles in 43 genotypes, -α3.7/αα and ßCd39C>T/ß were the most frequent. Four α-thal deletions (-Mex4 included HBA2 and HBA1, whereas (αα)Mex5, Mex6 and Mex7 involved MCS-R), a hereditary persistence of fetal hemoglobin-2 like (HPFH-2 like) deletion and six alleles not previously reported in Mexicans (α-59C>Tα, -α4.2, αPlasenciaα, ß-32C>T, ßInitCdA>C and ßFSCd71/72+A) were identified. Conclusion: The observed alleles denote the high heterogeneity and multiple origin admixture of Mexican population. Hematological data are consistent with genotypes, variability in simple carriers, from asymptomatic forms to mild or moderate anemia, was ascertained. We emphasize the importance to consider hematological parameters to establish adequate molecular screening strategies.

A novel p.Gly417Valfs*12 mutation in the MTTP gene causing abetalipoproteinemia: Presentation of the first patient in Mexico and analysis of the previously reported cases.

BACKGROUND: Our aims were to describe the first Mexican patient with abetalipoproteinemia and to perform a comparative analysis of biochemical, clinical, and genetic characteristics of 100 cases reported in the literature. METHODS: We performed biochemical and molecular screenings in a Mexican girl with extremely low lipid levels and in her family. Further, we integrated and evaluated the characteristics of the cases with abetalipoproteinemia described in the literature. RESULTS: Our patient is a six-year-old girl who presented vomiting, chronic diarrhea, failure to thrive, malabsorption, acanthocytosis, anemia, transaminases elevation, and extremely low lipid levels. MTTP gene sequencing revealed homozygosity for a novel mutation p.Gly417Valfs*12 (G deletion c.1250). With the analysis of the reported cases, 60 clinical features (14 classical and 46 non-classical) were observed, being the most common acanthocytosis (57.5%), malabsorption (43.7%), and diarrhea (42.5%); 48.8% of the patients presented only classic clinical features, while the remaining 51.2% developed secondary effects due to a fat-soluble vitamin deficiency. An odds ratio analysis disclosed that patients diagnosed after 10 years of age have an increased risk for presenting clinical complications (OR = 18.0; 95% CI 6.0-54.1, p < 0.0001). A great diversity of mutations in MTTP has been observed (n = 76, being the most common p.G865X and p.N139_E140) and some of them with possible residual activity. CONCLUSION: The first Mexican patient with abetalipoproteinemia presents a novel MTTP mutation p.Gly417Valfs*12. Three factors that could modulate the phenotype in abetalipoproteinemia were identified: age at diagnosis, treatment, and the causal mutation.

Association of the -629C>A (rs1800775) CETP Polymorphism with the Development of Essential Hypertension in Mexican Population.

Introduction: Polymorphisms in the CETP gene promoter have been associated with cardiovascular risk and lipid alterations; however, their role in the development of hypertension has not been extensively explored. We evaluated four polymorphisms of the CEPT gene -827C>T, -631C>A, -630C>A, and -629C>A in patients with essential hypertension (EH). Materials and Methods: A total of 160 hypertensive (HT) patients and 160 normotensive (NT) individuals were studied. Blood pressure was measured and blood samples were collected for biochemical anlayses and DNA extraction. Polymorphisms were identified using Sanger sequencing. Genotype, genotype combination, allele, and haplotype frequencies were analyzed. Associations between the SNPs and EH were explored using multiple linear regression models. Results: Under the dominant model, the -629A allele reduced the odds of having EH (odds ratio [OR] = 0.58, 95% confidence interval [CI], 0.34-0.98; p = 0.04), whereas the genotype combination -631CC/-629CC increased the risk of HT (OR = 2.21, 95% CI, 1.23-3.95, p = 0.008). In HT patients, the -629A allele was associated with increased insulin levels (ß = 4.0, 95% CI, 1.21-6.68, p = 0.005), and homeostatic model assessment of insulin resistance (ß = 0.9, 95% CI, 0.17-1.72, p = 0.018), and in NT individuals it was associated with increased high-density lipoprotein cholesterol levels (ß = 3.0, 95% CI, 0.20-5.78, p = 0.036). Conclusion: The CETP -629A allele reduces the odds of having essential arterial hypertension in the Mexican population. Moreover, it exerts a variable effect on diverse biomarkers analyzed in both NT and HT groups.

The Relationship of Single Nucleotide Polymorphisms in the TRPV1 Gene with Lipid Profile, Glucose, and Blood Pressure in Mexican Population.

Aim: We analyzed the frequencies of the rs222749 G>A, rs222747 G>C, rs224534 G>A, and rs8065080 C > T polymorphisms in the TRPV1 gene and their relationships with biomarkers in a Mexican population. Materials and Methods: We included 195 students from two Mexican universities (72.3% female and 27.7% male, mean age, 20.8 ± 3.3 years). The biomarkers analyzed were lipid profile, glucose levels, blood pressure (BP), and body mass index. DNA was obtained from leukocytes by the dodecyltrimethylammonium bromide and cetyltrimethylammonium bromide method and polymorphisms were determined with TaqMan single nucleotide polymorphism (SNP) genotyping assays. Results: Alterations in lipid profile were total cholesterol ≥200 mg/dL in 9.7% of participants, triglycerides (TG) ≥150 mg/dL in 9.2%, high-density lipoprotein (HDL) <35 mg/dL in 6.7%, and low-density lipoprotein (LDL) ≥130 mg/dL in 6.2% of participants. Moreover, 8.2% of the subjects had BP values consistent with hypertension. The most frequent alleles were rs222749G (89.2%), rs222747G (69.2%), rs224534G (59.7%), and rs8065080T (62.3%). An analysis of the associations between the genotypic data and the biomarkers showed that the rs222749GA and rs224534GA genotypes were associated with higher diastolic and systolic BP values, respectively; the rs222747CC genotype was associated with lower LDL levels; the rs224534AA genotype was associated with higher HDL levels and lower triglycerides and LDL. The GGGC/GCAT and GGGT/GCAT haplotypes were associated with higher systolic BP. Conclusions: This study suggests a possible association between TRPV1 gene polymorphisms and BP and lipid profiles in a Mexican population.

LDLR Gene Mutation p.Asp360His and Familial Hypercholesterolemia in a Mexican Community.

BACKGROUND: Familial hypercholesterolemia (FH) is an autosomal dominant disease characterized by an increased LDL-cholesterol (LDLc) serum concentration and premature cardiovascular disease. Screening of small populations where at least one homozygous (HoFH) patient has been identified may be a proper approach for detecting FH patients. Previously, we reported an HoFH patient carrying the mutation p.Asp360His LDLR, who was born in the Mexican community El Triunfo (Quimixtlan, Puebla). AIM OF THE STUDY: To identify patients with familial hypercholesterolemia in the community El Triunfo and to describe their clinical and biochemical characteristics. METHODS: We studied 308 individuals by quantifying lipid levels and by DNA sequencing. RESULTS: Sixteen of 308 individuals presented an LDLc level >170 mg/dL and all of them turned out to be heterozygous for the LDLR p.Asp360His variant. Subsequently, 34 of their first-degree relatives (mainly siblings and parents) were genotyped rendering six additional HeFH patients, which resulted in 22 carriers of the mutated allele. The study of six LDLR polymorphisms in four unrelated individuals from the community (one HoFH and three HeFH) showed the same haplotype combination, suggesting a unique ancestral origin of the mutation. CONCLUSIONS: The community El Triunfo, has the highest worldwide frequency ever reported of HeFH, with 7.14% (22/308, equivalent to 1/14 inhabitants). Since the HeFH patients showed variable biochemical expression, we suggest looking for factors with the potential to modify the phenotype. Finally, we stress the importance of establishing accurate LDLc cut-off points applicable to Mexican population for the diagnosis of FH.

Prevalence of the BRAF p.v600e variant in patients with colorectal cancer from Mexico and its estimated frequency in Latin American and Caribbean populations.

This study aimed to investigate the frequency of the somatic BRAF p.V600E in patients with colorectal cancer (CRC) in Mexico and compare it with those estimated for Latin American and Caribbean populations. One hundred and one patients with CRC with AJCC stages ranging I-IV from Western Mexico were included, out of which 55% were male and 61% had AJCC stage III-IV, with a mean age of 60 years. PCR-Sanger sequencing was used to identify the BRAF p.V600E variant. In addition, a systematic literature search in PubMed/Medline database and Google of the 42 countries in Latin America and the Caribbean led to the collection of information on the BRAF p.V600E variant frequency of 17 population reports. To compare the BRAF variant prevalence among populations, a statistical analysis was performed using GraphPad Prism V.6.0. We found that 4% of patients with CRC were heterozygous for the p.V600E variant. The χ2 test showed no significant difference (p>0.05) in p.V600E detection when comparing with other Latin American and Caribbean CRC populations, except for Chilean patients (p=0.02). Our observational study provides the first evidence on the frequency of BRAF p.V600E in patients with CRC from Western Mexico, which is 4%, but increases to 7.8% for all of Latin America and the Caribbean. The patient mean age and genetic descent on the observed frequencies of the variant in populations could influence the frequency differences.

BCR/ABL1 Transcripts in Healthy Individuals: A Comparative Analysis Between First-Degree Relatives of Patients with Chronic Myelogenous Leukemia and Subjects without Antecedents of the Disease.

BCR/ABL1 transcripts, the molecular hallmarks of chronic myeloid leukemia (CML), have been detected in peripheral blood from healthy individuals. Although CML is a sporadic disease, familial occurrence has been reported. This raises the question of whether there is a hereditary factor related to the etiology of CML. Our aim is to compare the BCR/ABL1 e13a2 and e14a2 transcript frequency in healthy first-degree relatives of families with CML versus individuals from families without CML antecedents. Ninety-eight healthy individuals, sorted into two groups, were studied: a group consisting of 46 first-degree relatives from families having a CML affected, and another with 52 healthy individuals from families without CML antecedents. BCR/ABL1 e13a2 and e14a2 transcripts were detected in mRNA isolated from peripheral blood leukocytes. We observed 28 of 98 individuals positive for at least one BCR/ABL1 transcript: e14a2 was detected in 22, e13a2 in 4, and co-expression was observed in 2 subjects. The positivity rate in relatives of CML cases was 33%, whereas individuals without CML antecedents had a 25% positivity rate, showing no statistical difference. Our results corroborate the presence of e13a2 and e14a2 BCR/ABL1 transcripts in the peripheral blood of healthy individuals, but has not a found familial factor related to the etiology of this rearrangement.

Genomic instability in a chronic lymphocytic leukemia patient with mono-allelic deletion of the DLEU and RB1 genes.

BACKGROUND: The most frequent cytogenetic abnormality detected in chronic lymphocytic leukemia (CLL) patients is the presence of a deletion within the chromosome band 13q14. Deletions can be heterogeneous in size, generally encompassing the DLEU1 and DLEU2 genes (minimal deleted region), but at times also including the RB1 gene. The latter, larger type of deletions are associated with worse prognosis.Genomic instability is a characteristic of most cancers and it has been observed in CLL patients mainly associated with telomere shortening. CASE PRESENTATION: Cytogenetic and fluorescence in situ hybridization studies of a CLL patient showed a chromosomal translocation t(12;13)(q15;q14), a mono-allelic 13q14 deletion encompassing both the DLEU and RB1 genes, and genomic instability manifested as chromosomal breaks, telomeric associations, binucleated cells, nucleoplasmic bridges, and micronucleated cells.In conclusion, our CLL patient showed genomic instability in conjunction with a 13q14 deletion of approximately 2.6 megabase pair involving the DLEU and RB1 genes, as well as other genes with potential for producing genomic instability due to haploinsufficiency.

CDH1 somatic alterations in Mexican patients with diffuse and mixed sporadic gastric cancer.

BACKGROUND: Diffuse gastric cancer (DGC) is associated with the reduction or absence of the expression of the cell adhesion protein E-cadherin (encoded by the CDH1 gene). Molecular characteristics are less well described for mixed gastric cancer (MGC). The main somatic alterations that have been described in the CDH1 gene are mutations, loss of heterozygosity (LOH) and promoter methylation. The aim was to analyze CDH1 somatic alterations in Mexican patients with diffuse and mixed gastric cancer. METHODS: We searched for mutations in the CDH1 gene in tumor DNA from DGC (n = 13) and MGC (n = 7) patients by next generation sequencing (NGS). Validation of findings was performed using Sanger sequencing. LOH was analyzed using dinucleotide repeat markers surrounding the CDH1 gene, and methylation was investigated by DNA bisulfite conversion and sequencing. E-cadherin protein deficiency was analyzed by immunohistochemistry. RESULTS: Seventeen point variants were identified by NGS, 13 of them were validated by Sanger sequencing. Only 1/13 had not been previously reported (c.-137C > A), and 12/13 were already reported as polymorphisms. Two DGC cases presented LOH at the locus 16q22.1 (13.3%). CDH1 promoter methylation was positive in (7/11) 63.6% and (4/6) 66.6% of the cases with DGC and MGC, respectively. E-cadherin protein deficiency was observed in 58.3% of DGC cases while 100% in MGC cases. CONCLUSIONS: While no pathogenic somatic mutations were found that could explain the diffuse histology of gastric cancer in DGC and MGC, methylation was the most common somatic inactivation event of the CDH1 gene, and LOH was rare. The previously unreported c.-137C > A variant modify the CDH1 gene expression since it alters the binding sites for transcription factors.

Screening of LDLR and APOB gene mutations in Mexican patients with homozygous familial hypercholesterolemia.

BACKGROUND: Familial hypercholesterolemia (FH) is an autosomal dominant disorder that causes accumulation of serum low-density lipoprotein cholesterol and premature cardiovascular disease. It is mainly related to mutations in the LDLR gene. Homozygous FH (HoFH) patients have the most severe form of the disease accounting for a worldwide prevalence of 1:1,000,000. In Mexico, at least 5 cases of HoFH have been reported. OBJECTIVE: The aim of this study was to describe the clinical, biochemical, and molecular data observed in patients with HoFH phenotype. METHODS: We included 13 patients, belonging to 11 families, with clinical and biochemical diagnoses suggestive of HoFH. Molecular analyses of the LDLR and APOB genes were performed by means of polymerase chain reaction followed by Sanger sequencing. RESULTS: The causal mutation of HoFH was found in 8 of 11 unrelated patients. Excepting 1, all were true homozygotes. Six different variants in LDLR were identified: c.-139delCTCCCCCTGC, p.Glu140Lys, p.Asp360His, p.Asn405Lys, p.Ala755Glyfs*7, and p.Leu759Serfs*6. Of these, p.Asp360His and p.Asn405Lys were detected for the first time in Mexico; p.Leu759Serfs*6 showed to be the most frequent (43.7% of the alleles 7/16), and c.-139delCTCCCCCTGC is a new variant located in the promoter region. CONCLUSIONS: This work increases knowledge of biochemical and genetic features in Mexican patients with HoFH. A novel mutation in the LDLR gene promoter was detected: c.-139delCTCCCCCTGC, which possibly inhibits its expression.

Detection of monoclonal B cells in general population from two different regions of Mexico.

To estimate the frequency of monoclonal B cells in Mexican general population from two different regions of Mexico. Monoclonal B cells were detected by rearrangements of the immunoglobulin heavy chains (IGH) in 288 individuals: 188 from a metropolitan area and 100 from a rural area. After DNA extraction from peripheral blood by the CTAB/DTAB method, multiplex PCR was used to amplify the IGH rearrangements, followed by capillary electrophoresis. In together, 9.4% of the studied individuals showed monoclonal B cells. This prevalence is significantly higher to those previously described for other populations, but similar to a report in the Spanish population. Among people from the metropolitan area, 12.8% exhibited monoclonal B cells in comparison with 3% of people from the rural area. All individuals showing monoclonal B cells were elder than 40 years. Higher frequency of incomplete monoclonal rearrangements was observed. Individuals from urban areas show significantly increased frequencies of monoclonal B cells regarding the people from the rural area. It is reasonable to believe that the environmental factor could have a greater impact on the development of monoclonality than the genetic component.

Frecuencia, aspectos clínicos y moleculares de la hipercolesterolemia familiar en una unidad de endocrinología de Ciudad Bolívar, Venezuela / Frequency and clinical and molecular aspects of familial hypercholesterolemia in an endocrinology unit in Ciudad Bolívar, Venezuela

Objetivo: Describir la frecuencia, los aspectos clínicos, bioquímicos y moleculares de la hipercolesterolemia familiar (HF) en sujetos que acuden a una unidad de endocrinología. Métodos: Estudio observacional, descriptivo en el que se evaluaron 3.140 sujetos que fueron atendidos en la Unidad de Endocrinología del Centro Médico Orinoco en Ciudad Bolívar, Venezuela, desde el 7 de enero del 2013 al 9 de diciembre del 2016. Los casos índice fueron seleccionados de acuerdo con los criterios de la Red de Clínicas de Lípidos de Holanda. Se midieron lípidos plasmáticos. El análisis molecular se realizó por medio de secuenciación de ADN de los genes LDLR y APOB. Resultados: De los 3.140 sujetos evaluados, 10 (0,32%) tuvieron características clínicas y bioquímicas compatibles con HF. Todos, excepto uno, eran de sexo femenino. Tres pacientes tuvieron antecedente familiar en primer grado de enfermedad coronaria prematura y ninguno antecedente personal de esta patología. Tres pacientes tuvieron obesidad, 3 hipertensión arterial y ninguno tuvo diabetes. Tres pacientes presentaban xantomas tendinosos y solo uno arco corneal. Los valores de c-LDL oscilaron entre 191 y 486mg/dl. Solo 2 recibían tratamiento con estatinas. En 4 pacientes se identificó la causa genética de la HF: 3 de ellos por mutaciones en el gen LDLR y uno por mutación en el exón 26 del gen APOB. Conclusión: Aproximadamente una de cada 300 personas que acuden a consulta en esta unidad de endocrinología presentan HF. Las mutaciones en el gen LDLR son las principales causantes de HF en este grupo de pacientes (AU)

Objective: To assess the frequency and the clinical, biochemical, and molecular aspects of familial hypercholesterolemia (FH) in subjects attending an endocrinology unit. Methods: An observational, descriptive study evaluating 3,140 subjects attending the endocrinology unit of Centro Médico Orinoco in Ciudad Bolívar, Venezuela, from 7 January 2013 to 9 December 2016. The index cases were selected using the Dutch Lipid Clinic Network criteria. Plasma lipid levels were measured, and a molecular analysis was performed by DNA sequencing of the LDLR and APOB genes. Results: Ten (0.32%) of the 3,140 study patients had clinical and biochemical characteristics consistent with FH. All but one were female. Three had first-degree relatives with prior premature coronary artery; and none had a personal history of this condition. Three patients were obese; three had high blood pressure; and no one suffered from diabetes. Three patients had a history of tendon xanthomas, and one of corneal arcus. LDL-C levels ranged from 191 to 486mg/dL. Two patients were on statin therapy. The genetic causes of FH were identified in four patients, and were LDLR gene mutations in three of them and an APOB gene mutation in exon 26 in the other. Conclusion: Approximately, one out of every 300 people attending this endocrinology unit in those four years had FH, and LDLR gene mutations were the most prevalent cause (AU)

Frequency and clinical and molecular aspects of familial hypercholesterolemia in an endocrinology unit in Ciudad Bolívar, Venezuela. / Frecuencia, aspectos clínicos y moleculares de la hipercolesterolemia familiar en una unidad de endocrinología de Ciudad Bolívar, Venezuela.

OBJECTIVE: To assess the frequency and the clinical, biochemical, and molecular aspects of familial hypercholesterolemia (FH) in subjects attending an endocrinology unit. METHODS: An observational, descriptive study evaluating 3,140 subjects attending the endocrinology unit of Centro Médico Orinoco in Ciudad Bolívar, Venezuela, from 7 January 2013 to 9 December 2016. The index cases were selected using the Dutch Lipid Clinic Network criteria. Plasma lipid levels were measured, and a molecular analysis was performed by DNA sequencing of the LDLR and APOB genes. RESULTS: Ten (0.32%) of the 3,140 study patients had clinical and biochemical characteristics consistent with FH. All but one were female. Three had first-degree relatives with prior premature coronary artery; and none had a personal history of this condition. Three patients were obese; three had high blood pressure; and no one suffered from diabetes. Three patients had a history of tendon xanthomas, and one of corneal arcus. LDL-C levels ranged from 191 to 486mg/dL. Two patients were on statin therapy. The genetic causes of FH were identified in four patients, and were LDLR gene mutations in three of them and an APOB gene mutation in exon 26 in the other. CONCLUSION: Approximately, one out of every 300 people attending this endocrinology unit in those four years had FH, and LDLR gene mutations were the most prevalent cause.

Clinical and molecular aspects of familial hypercholesterolemia in Ibero-American countries.

BACKGROUND: There is little information about familial hypercholesterolemia (FH) epidemiology and care in Ibero-American countries. The Ibero-American FH network aims at reducing the gap on diagnosis and treatment of this disease in the region. OBJECTIVE: To describe clinical, molecular, and organizational characteristics of FH diagnosis in Argentina, Brazil, Chile, Colombia, Mexico, Portugal, Spain, and Uruguay. METHODS: Descriptive analysis of country data related to FH cascade screening, molecular diagnosis, clinical practice guidelines, and patient organization presence in Ibero-America. RESULTS: From a conservative estimation of an FH prevalence of 1 of 500 individuals, there should be 1.2 million heterozygous FH individuals in Ibero-America and roughly 27,400 were diagnosed so far. Only Spain, Brazil, Portugal, and Uruguay have active cascade screening programs. The prevalence of cardiovascular disease ranged from 10% to 42% in member countries, and the highest molecular identification rates are seen in Spain, 8.3%, followed by Portugal, 3.8%, and Uruguay with 2.5%. In the 3 countries with more FH patients identified (Spain, Portugal, and Brazil) between 10 and 15 mutations are responsible for 30% to 47% of all FH cases. Spain and Portugal share 5 of the 10 most common mutations (4 in low density lipoprotein receptor [LDLR] and the APOB3527). Spain and Spanish-speaking Latin American countries share 6 of the most common LDLR mutations and the APOB3527. LDL apheresis is available only in Spain and Portugal and not all countries have specific FH diagnostic and treatment guidelines as well as patient organizations. CONCLUSIONS: Ibero-American countries share similar mutations and gaps in FH care.