Homozygous familial hypobetalipoproteinemia caused by APOB gene variations: a case report and review of literature / 中华儿科杂志

Objective: To summarize the genotypes and clinical characteristics of homozygous family hypobetalipoproteinemia (Ho-FHBL) caused by apolipoprotein B (APOB) gene variations. Methods: The clinical, laboratory, genetic, and liver histology data of a boy with Ho-FHBL managed in the hepatology ward of the Children's Hospital of Fudan University in May 2021 were retrospectively analyzed. The literature was searched from China National Knowledge Infrastructure, Wanfang Data Knowledge Service Platform, China VIP database, China Biology Medicine disc and PubMed database (up to May 2022) with "familial hypobetalipoproteinemia" or "hypobetalipoproteinemias" or "hypo beta lipoproteinemia" or "hypolipoproteinemias" as the search terms. All relevant literatures were reviewed to summarize the clinical and genetic features of Ho-FHBL caused by APOB gene variations. Results: The male patient was admitted to the hospital due to abnormal liver function tests for 8 months at the age of 4 years and 6 months. Blood biochemistry showed transaminitis and abnormally low serum levels of lipids. Liver biopsy revealed fatty liver with inflammation and early cirrhosis (Brunt score was F3G2S4). Whole exome sequencing revealed two novel variants of APOB gene (c.3745C>T, p.Q1249 * from the father and c.4589_4592delinsAGGTAGGAGGTTTAACTCCTCCTACCT, p.T1530Kfs * 12 from the mother). He was diagnosed as Ho-FHBL caused by APOB gene compound heterozygous variations. Literature search retrieved 36 English literatures and 0 Chinese literature. A total of 55 (23 males and 32 females) Ho-FHBL cases, including this one, were caused by 54 APOB gene pathogenic variants (23 frameshift, 15 nonsense, 7 missense, 8 splice and 1 gross deletions). The age of the last follow-up was between 1 month and 75 years. Among them, 28 cases had lipid malabsorption, 19 cases had early dysplasia, 12 cases had no symptoms. Twenty-one patients had symptoms related to fat soluble vitamin deficiency, including 14 cases of acanthocytosis, 10 cases of neurological symptoms, and 6 cases of ocular lesions. Thirty-four patients had liver involvement, including 25 cases of elevated transaminase, 21 cases of fatty liver, 15 cases of hepatomegaly, 9 cases of liver fibrosis, 3 cases of liver cirrhosis, 1 case of hepatic hemangioma and 1 case of liver neoplastic nodule. Conclusions: The variants of APOB gene in Ho-FHBL are mainly frameshift and nonsense variations. Patients may have lipid malabsorption and (or) early dysplasia, or symptom-free. Liver involvement is common.

Analysis of the association of CYP450 gene polymorphisms with ischemic stroke / 中华医学遗传学杂志

OBJECTIVE@#To assess the association of cytochrome P450 (CYP450) gene polymorphisms with the occurrence of ischemic stroke (IS).@*METHODS@#From January 2020 to August 2022, 390 IS patients treated at the Zhengzhou Seventh People's Hospital were enrolled as the study group, and 410 healthy individuals undergoing physical examination during the same period were enrolled as the control group. Clinical data of all subjects were collected, which included age, sex, body mass index (BMI), smoking history and results of laboratory tests. Chi-square test and independent sample t test were used for comparing the clinical data. Multivariate logistic regression analysis was used to analyze the non-hereditary independent risk factors for IS. Fasting blood samples of the subjects were collected, and the genotypes of rs4244285, rs4986893, rs12248560 of the CYP2C19 gene and rs776746 of the CYP3A5 gene were determined by Sanger sequencing. The frequency of each genotype was calculated by using SNPStats online software. The association between the genotype and IS under the dominant, recessive and additive models was analyzed.@*RESULTS@#The levels of total cholesterol (TC), triglyceride (TG), low density lipoprotein (LDL-C), apolipoprotein B (Apo-B) and homocysteine (Hcy) of the case group were significantly higher than those of the control group, whilst the levels of high density lipoprotein (HDL-C) and Apo-A1 (APO-A1) were significantly lower (P < 0.05). Multivariate Logistic regression analysis showed that TC (95%CI = 1.13-1.92, P = 0.02), LD-C (95%CI = 1.03-2.25, P = 0.03), Apo-A1 (95%CI = 1.05-2.08, P = 0.04), Apo-B (95%CI = 1.7-4.22, P < 0.01) and Hcy (95%CI = 1.12-1.83, P = 0.04) were non-genetic independent risk factors for the occurrence of IS. Analysis of the association between the genetic polymorphisms and the risk of IS showed that the AA genotype at rs4244285 of the CYP2C19 gene, the AG genotype and A allele at rs4986893 of the CYP2C19 gene, and the GG genotype and G allele at rs776746 of the CYP3A5 gene were significantly associated with IS. Under the recessive/additive model, dominant model and dominant/additive model, polymorphisms of the rs4244285, rs4986893 and rs776746 loci were also significantly associated with the IS.@*CONCLUSION@#TC, LDL-C, Apo-A1, Apo-B and Hcy can all affect the occurrence of IS, and CYP2C19 and CYP3A5 gene polymorphisms are closely associated with the IS. Above finding has confirmed that the CYP450 gene polymorphisms can increase the risk of IS, which may provide a reference for the clinical diagnosis.

The APOB rs693 polymorphism impacts the lipid profile of Brazilian older adults

The apolipoprotein B (APOB) gene contains several polymorphic sites described as risk modifiers for cardiovascular events. The objective of this study was to verify the association of the classic APOB Xba I polymorphism (rs693) with atherosclerotic risk factors in a segment of the Brazilian elderly population considering their usual dietary intake. Clinical and biochemical characteristics as well as total caloric and fat intake data were determined from 644 elderly individuals. Polymorphism analysis was performed by conventional polymerase chain reaction followed by enzyme restriction. Statistical analyses compared measures and proportions according to different APOB genotypic combinations. Statistically significant association was found between Xba I polymorphism and serum LDL, total cholesterol, and total lipid levels, with important elevations among T homozygotes compared to the other genotypes. There was homogeneity in all other parameters analyzed (including intake pattern), with a tendency for reduced levels of circulating apolipoprotein B among TT individuals. Our results pointed out that genetic variation in APOB affected the lipemic profile of elderly individuals in a context not biased by diet, generating a pattern suggestive of secretory disorder of lipoprotein particles, with possible implication in atherosclerotic risk.

High levels of chemerin associated with variants in the NOS3 and APOB genes in rural populations of Ouro Preto, Minas Gerais, Brazil

Chemerin is an adipokine that has been associated with components of metabolic syndrome. It has been described to affect adipocyte metabolism and inflammatory responses in adipose tissue, as well as the systemic metabolism of lipids and glucose. Few epidemiological studies have evaluated classical and genetics cardiovascular risk factors (CVRFs) in the mixed adult rural population in Brazil. Therefore, the present study explored possible associations between CVRFs and chemerin. This cross-sectional study included 508 adults from the rural localities of Lavras Novas, Chapada, and Santo Antônio do Salto in Ouro Preto, Minas Gerais, Southeast Brazil. Demographic, behavioral, clinical, biochemical, anthropometric variables, and 12 single nucleotide polymorphisms (SNPs) linked with metabolic syndrome phenotypes were evaluated for associations with chemerin level. There was a significant association of high triglyceride levels [odds ratio (OR)=1.91, 95%CI: 1.23−2.98], insulin resistance (OR=1.82, 95%CI: 1.03−3.22), age (OR=1.64, 95%CI: 1.08−2.49), and sex (OR=1.99, 95%CI: 1.35−2.95) with high levels of chemerin. High chemerin levels were significantly associated with the genetic polymorphisms rs693 in the APOB gene (OR=1.50, 95%CI: 1.03−2.19) and rs1799983 in the NOS3 gene (OR=1.46, 95%CI: 1.01−2.12) for the AA and GT+TT genotypes, respectively. In the concomitant presence of genotypes AA of rs693 and GT+TT of rs1799983, the chance of presenting high levels of chemerin showed a 2.21-fold increase (95%CI: 1.25−3.88) compared to the reference genotype. The development of classical CVRFs in this population may be influenced by chemerin and by two risk genotypes characteristic of variants in well-studied genes for hypertension and dyslipidemia.

Distribution of polymorphism rs693 of ApoB gene in a sample of Colombian Caribbeans / Distribución del polimorfismo rs693 en el gen de la apolipoproteína B en una muestra caribeños colombianos

Abstract Introduction: Several studies have reported that the single nucleotide polymorphism rs693 of Apo lipoprotein B gene is associated with high levels of plasma lipids and high body mass index, which are risk factors for cardiovascular diseases. The distribution of this single nucleotide polymorphism and its association with the phenotype depend on the genetic background of each population. Objective: To evaluate the distribution of single nucleotide polymorphism rs693 and its association with lipid profile and body mass index in a sample of Colombian Caribbeans. Methods: 108 non-related adult subjects of both gender were included in this study. Body mass index and lipid profile that included total cholesterol, triglycerides, Low Density Lipoprotein and High Density Lipoprotein were determined. The single nucleotide polymorphism rs693 was determined by Polymerase Chain Reaction/Restriction Fragment Length Polymorphism from genomic DNA followed by digestion with the restriction enzyme XbaI. The chi-square test was used to analyze the genotype distribution of rs693 and the genotype-phenotype association was evaluated through different inheritance model. Results: The genotype frequencies for single nucleotide polymorphism rs693 were CC (45.0%), TT (16.5%) and CT (38.5%). The allele frequencies were C (64.0%) and T (36.0%). The single nucleotide polymorphism was in Hardy-Weinberg equilibrium in the studied sample. No association of the single nucleotide polymorphism rs693 with lipid profile nor the body mass index was found (p >0.05). Conclusion: There is no significant association between single nucleotide polymorphism rs693 and body mass index nor lipid profile, in a sample of Colombian Caribbeans.

Resumen Introducción: Varios estudios han informado que el polimorfismo de un solo nucleótido rs693 del gen de la apolipoproteína B se asocia con altos niveles de lípidos plasmáticos e índice de masa corporal, los cuales son factores de riesgo para enfermedades cardiovasculares. La distribución de este polimorfismo y su asociación con el fenotipo dependen del antecedente genético de cada población. La población caribeña colombiana es producto de la mezcla de tres grupos étnicos principales: africano, amerindio y caucásico. Objetivo: Evaluar la distribución del polimorfismo rs693 y su asociación con el perfil lipídico y el índice de masa corporal en una muestra de sujetos caribeños colombianos. Métodos: Fueron incluidos en este estudio 108 sujetos adultos de ambos sexos y no relacionados. Se determinaron el índice de masa corporal y el perfil lipídico; de éste se incluyó colesterol total, triglicéridos, lipoproteínas de baja densidad y lipoproteína de alta densidad. El polimorfismo rs693 se determinó mediante Reacción en Cadena de la Polimerasa del ADN genómico seguida por digestión con la enzima de restricción XbaI. Se utilizó la prueba de ji cuadrado para analizar la distribución del genotipo de rs693 y se evaluó la asociación genotipo-fenotipo a través de diferentes modelos de herencia. Resultados: Las frecuencias genotípicas para rs693 fueron CC (45.0%), TT (16.5%) y TC (38.5%). Las frecuencias alélicas fueron C (64.0%) y T (36.0%). El polimorfismo rs693 estaba en equilibrio de Hardy-Weinberg en la muestra estudiada y no presentó asociación con el perfil lipídico ni con el índice de masa corporal (p >0.05). Conclusión: No existe asociación significativa del polimorfismo rs693 con el índice de masa corporal ni con el perfil lipídico en una muestra de caribeños colombianos.

Apolipoprotein B and angiotensin-converting enzyme polymorphisms and aerobic interval training: randomized controlled trial in coronary artery disease patients

Physical training has been strongly recommended as a non-pharmacological treatment for coronary artery disease (CAD). Genetic polymorphisms have been studied to understand the biological variability in response to exercise among individuals. This study aimed to verify the possible influence of apolipoprotein B (ApoB: rs1042031 and rs693) and angiotensin-converting enzyme (ACE-ID: rs1799752) genotypes on the lipid profile and functional aerobic capacity, respectively, after an aerobic interval training (AIT) program in patients with CAD and/or cardiovascular risk factors. Sixty-six men were randomized and assigned to trained group (n=32) or control group (n=34). Cardiopulmonary exercise test was performed to determine the ventilatory anaerobic threshold (VAT) from cardiorespiratory variables. The AIT program, at an intensity equivalent to %VAT (70-110%), was conducted three times a week for 16 weeks. ApoB gene polymorphisms (−12669C>T (rs1042031) and −7673G>A (rs693)) were identified by real-time polymerase chain reaction (PCR). I/D polymorphism in the ACE gene (rs1799752) was identified through PCR and fragment size analysis. After 16 weeks, low-density lipoprotein (LDL) levels increased in the trained and control groups with the GA+AA genotype (−7673G>A) of the ApoB gene. Trained groups with ACE-II and ACE-ID genotypes presented an increase in oxygen consumption (VO2VAT) and power output after the AIT program. The presence of the ACE I-allele was associated with increased aerobic functional capacity after the AIT program. Increased LDL levels were observed over time in patients with the −7673G>A polymorphism of the ApoB gene. Trial Registration Information: ClinicalTrials.gov: NCT02313831

Association between polymorphisms in the APOB gene and hyperlipidemia in the Chinese Yugur population

We investigated the influence of apolipoprotein B gene (APOB) variants on the risk of hyperlipidemia (HL) in 631 middle-aged and elderly members of the Chinese Yugur population (HL, n=336; normolipidemia, n=295). APOB polymorphisms were identified using mass spectrometry, and five single nucleotide polymorphisms (rs1042034, rs2163204, rs512535, rs676210, and rs679899) and serum lipids were further analyzed. rs1042034 and rs676210 were significantly associated with HL (P<0.05). Compared with the GG or AA genotype, individuals with AG and AG+AA in rs1042034 and with AG and AG+GG in rs676210 had a 1.67-fold (95%CI=1.20-2.33),1.63-fold (95%CI=1.19-2.24), 1.72-fold (95%CI=1.24-2.40), and 1.67-fold (95%CI=1.21-2.291) increased risk of high HL, respectively. rs2163204 was in strong linkage disequilibrium with rs1042034, rs676210, and rs679899, and strong disequilibrium was observed between rs1042034 and rs676210 (D′>0.9). Compared with the GTGAA haplotype, haplotypes ATGGA and ATAGG were more strongly associated with HL [odds ratio (OR)=1.46, 95%CI=0.02-2.11; OR=1.63, 95%CI=1.03-2.60, respectively]. The risk factors age (P=0.008), body mass index (P<0.0001), GA+GG genotype in rs676210 (P=0.009), and alcohol consumption (P=0.056) contributed strongly to HL development. The A allele of rs1042034 and the G allele of rs676210 may thus predispose middle-aged and elderly members of the Chinese Yugur population to HL in combination with other genetic or nutritional factors, and could be used as new genetic markers for HL screening.

Hipobetalipoproteinemia primária: relato de caso / Primary Hypobetalipoproteinemia: a case report

Descrevemos o caso de uma paciente de 19 anos diagnosticada com hipobetalipoproteinemia primária. A paciente apresentava sintomas compatíveis com a doença como diarreia desde o primeiro mês de vida, défice de crescimento e retinopatia. A biópsia duodenal evidenciou presença de vacúolos lipídicos intraepiteliais, os quais foram altamente sugestivos para o diagnóstico. Os exames complementares evidenciaram disfunção hepática, baixos níveis séricos de triglicerídeos, e de colesterol total e frações. Após a dosagem de apolipoproteína B abaixo dos valores da normalidade, aliada a clínica e exames complementares, o diagnóstico foi realizado. A relativa escassez de dados na literatura em nosso meio, atrelada à raridade da doença, ilustra a relevância deste relato de caso, somado à importância do diagnóstico precoce

The case of a 19-year-old female patient who was diagnosed with Primary Hypobetalipoproteinemia (HBL) is described.The patient presented symptoms that were consistent with the disease, such as diarrhea from the very first month of life, growth failure and retinopathy. The duodenal biopsy showed the presence of intraepithelial lipid vacuoles that were highly suggestive of the diagnosis. Further tests showed liver dysfunction, low serum levels of triglycerides and total cholesterol and fractions. After the dosage of Apolipoprotein B below normal values, and clinical exam along with laboratory tests, the diagnosis was made. The lack of data in the literature and the rarity of the disease illustrate the importance of this case report,and of an early diagnosis.

Association of apolipoprotein B XbaI gene polymorphism and lipid profile in northern Indian obese.

BACKGROUND: Over the last few decades, obesity, diabetes, and hypertension have become main health evils. The health problems of obesity are well-recognized. However, the fact that all obese individuals are not at the same risk of developing a disease is also recognized. The apolipoprotein B (APOB) plays a central role in lipid metabolism. So we compare the association of APOB XbaI gene polymorphism and lipid profile total in obese north Indian population. MATERIALS AND METHODS: A total of 132 obese (body mass index [BMI] >25 kg/m2) and 132 age matched non-obese (BMI ≤ 25 kg/m2) subjects were studied after taking detailed clinical profile. Lipid profile in serum/plasma was done using commercial kits. Genetic analysis of APOB XbaI was done using Polymerase Chain Reaction-Restriction Fragment Leanth polymorphism (PCR-RFLP). STATISTICAL ANALYSIS: Statistical analysis was performed by Statistical Package for the Social Sciences (SPSS) (version 11.5) software (IBM Corporation). All continuous variables were expressed as mean ± SD and tested by analysis of variance test. Comparisons of categorical variables were assessed using χ2 tests or Fisher's exact test. P < 0.05 was considered as significant. RESULTS: Analysis showed that obese subjects had significantly higher value of the waist-to-hip ratio, blood pressure (systolic and diastolic), and lipid profile. In APOB XbaI gene polymorphism, we did not find significant differences in genotype or allele frequencies. Moreover, none of the studied metabolic parameters (lipid profile) showed any association with the gene polymorphism. CONCLUSIONS: Study reveals no considerable association of APOB XbaI gene polymorphism with obesity and lipid profile in north Indians.

Frecuencia del polimorfismo E4154K del gen de la apolipoproteína B en individuos chilenos con perfil de riesgo para enfermedad coronaria / Frequency of the E4154K polymorphism at the apolipoprotein B gene in chilean individuals with high risk for coronary artery disease

Las enfermedades cardiovasculares son la principal causa de morbimortalidad en Chile. El conocimiento de los factores de riesgo asociados a estas patologías, puede ser importante en la prevención. Los objetivos del presente estudio fueron: a)evaluar la frecuencia del polimorfismo E4154K (EcoRI) del gen de la apolipoproteína B (APOB) en 60 individuos con perfil de riesgo para enfermedad coronaria (grupo de estudio, GE) y 120 controles (GC) de la ciudad de Temuco (Chile) y b) determinar el efecto de esta alteración molecular sobre las concentraciones plasmáticas de lípidos. La genotipificación del polimorfismo EcoRI fue realizada mediante la técnica de PCR, seguida de restricción enzimática. Nuestros resultados mostraron que el genotipo homocigoto E+E+ para el polimorfismo EcoRI fue significativamente mayor en los individuos del grupo GE (77 por ciento vs. 56 por ciento, p=0.018). Se observó también, que los individuos del grupo GE portadores del genotipo E+E+, presentaron mayores niveles de colesterol total (p=0.003), y bajos valores de HDL-C )p=0.008). En conclusión, nuestros datos demuestran una importante asociación entre el polimorfismo EcoRI del gen APOB y marcadores biológicos de riesgo cardiovascular.

Polymorphisms in the apolipoprotein B-100 gene: association with plasma lipid concentration and coronary artery disease.

BACKGROUND: The aim of this study was to investigate the association of apolipoprotein B gene polymorphisms with coronary artery disease and lipid levels in Indians. METHODS AND RESULTS: One hundred patients of angiographically proven atherosclerotic coronary artery disease and one hundred age- and sex-matched control subjects (treadmill negative) were included in the study. Serum lipids including cholesterol, triglycerides, high-density lipoprotein, low-density lipoprotein, very low-density lipoprotein, and apolipoprotein B were analyzed. Genomic DNA was extracted and the apolipoprotein B 3' hypervariable region amplified by polymerase chain reaction. Regions carrying Xba1, EcoR1, and Msp1 restriction sites present in the apolipoprotein B gene were amplified and digested separately by the respective enzymes. Restriction fragment length polymorphism analysis showed that EcoR1 with the R+/R+ genotype was significantly more common in patients with coronary artery disease. Overall, the genotypes EcoR1+/+, Msp1+/+, Xba1+/+ and Eco R1+/+ Msp1+/-, Xba1-/- were significantly more common in patients as compared to controls (p<0.05). When gene polymorphisms were compared with lipid abnormalities, the genotypes EcoR1+/+, Xba1-/-, and Msp1+/+ were more frequent in patients with elevated apolipoprotein B and very low-density lipoprotein levels. On the other hand, these genotypes were less common in patients with increased total cholesterol and low-density lipoprotein levels. When we studied the individual alleles of the variable number of tandem repeats region, we observed that allele 34 was significantly increased in patients with coronary artery disease as compared to controls. Allele 36 was present with a frequency of 1% in controls while it was totally absent in patients. CONCLUSIONS: This study identifies the apolipoprotein B gene polymorphism associated with coronary artery disease. An association between apolipoprotein B gene polymorphisms and elevated apolipoprotein B and very low-density lipoprotein levels was observed. However, there was no positive association with other elevated lipid levels in North Indians from Uttar Pradesh.

Expression and functional activity of receptor-Ck in mononuclear cells of a homozygous hypercholesterolemic family.

The study was addressed to explore the expression and functional activity of a novel cholesterol-specific cell surface receptor-Ck in a typical homozygous familial hypercholesterolemic family. Functional activity of receptor-Ck was characterized by its ability to downregulate Bcl-2 gene expression through a 47 kDa factor having an affinity for the sterol-regulatory element in the promoter region of this gene. The result of such a study revealed normal expression and functional activity of receptor-Ck accompanied by a lack of Apolipoprotein B-specific low-density lipoprotein receptor gene expression in the mononuclear cells derived from these patients. On the basis of these results, it is tempting to speculate that receptor-Ck may be involved in the maintenance of cellular cholesterol homeostasis observed in homozygous familial hypercholesterolemic patients.

Relationship of Xba1 and EcoR1 polymorphisms of apolipoprotein-B gene to dyslipidemia and obesity in Asian Indians in North India.

BACKGROUND: Genetic investigation of dyslipidemia and obesity prevalent in the Indian population form the basis of this study. METHODS AND RESULTS: The frequency of restriction fragment length polymorphisms (Xba1 and EcoR1) of the apolipoprotein-B gene was investigated in a case-control study of 30 hyperlipidemic and 40 normolipidemic subjects. By univariate analysis, old age, higher body mass index, waist-hip ratio and sum of four skinfolds were found to be significantly associated with hyperlipidemia. The frequencies of X- and E+ alleles of the apolipoprotein-B gene were significantly higher in North Indians in the state of New Delhi (0.83 and 0.91, respectively) as compared to the observations made in Caucasians in previous studies, but was similar to the frequency reported in Indians settled in Singapore and the UK. There were no significant differences in the allele or genotype frequencies of either Xba1 or EcoR1 polymorphisms between the hyperlipidemic and normolipidemic groups. On multiple logistic regression analysis considering body mass index, waist-hip ratio, percentage body fat and genotypes as independent variables, no association was observed between the apolipoprotein-B genotypes and serum lipid components. Further, there were no associations between apolipoprotein-B polymorphisms and generalized obesity (as assessed by body mass index, sum of four skinfolds, and percentage total body fat) and abdominal obesity (as measured by waist circumference and waist-hip ratio). CONCLUSIONS: We conclude that apolipoprotein-B (Xba1 and EcoR1) polymorphisms do not appear to influence serum lipid levels and parameters of generalized andregional obesity in the study sample.

The Haplotype Analyses Using Multiple Markers of the Apolipoprotein B Gene in Patients with Coronary Artery Disease

The high level of low density lipoprotein (LDL) is a risk factor for cardiovascular disease. Apolipoprotein (apo) B is a major protein component of LDL and plays an important role in the maintenance of cholesterol homeostasis. In this study, six polymorphic sites of the apoB gene were anlaysed in 235 patients with coronary artery disease (CAD) and 216 normal control subjects. There were no significant differences in the allele frequencies of apoB polymorphisms between the control and patient groups. However, haplotype frequencies were significantly different between the CAD patients and control (p<0.05). In addition, the allelic distributions of both EcoRI and MspI polymorphisms in Koreans were similar to those in Chinese but significantly different from those in Caucasians. ApoB polymorphisms showed no association with plasma lipid levels. In conclusion, haplotype analysis of the apoB gene using multiple diallelic markers might be a useful marker for Korean CAD patients.

Tipificacion del polimorfismo VNTR en el gen de apolipoproteina B en pacientes con enfermedad coronaria e hipercolesterolemia / Tipyfication of VNTR polymorphism in gene of apolipoproteina B for patient with coronary disease and hypercholesterolemia

La enfermedad coronaria es principal causa de morbilidad y mortalidad en el mundo. En Colombia la enfermedad coronaria, con los accidentes cerebrovasculares y la hipertensión arterial, es la segunda causa de mortalidad y discapacidad. El colesterol LDL (lipoproteína de baja densidad) elevado es factor de riesgo importante en el desarrollo de esta enfermedad. Un componente principal de las LDL es la apolipoproteína B cuyo gen contiene una región altamente polimórfica constituida por un número variable de repeticiones en tándem (VNTR). En este estudio mediante técnica de Reacción en Cadena de la Polimerasa (PCR) se estimaron frecuencias alélicas y distribución de este polimorfismo, se establecieron diferencias específicas del polimorfismo en asociación a enfermedad coronaria e hipercolesterolemia. Se realizó estudio de casos y controles. Se evaluaron 50 pacientes con enfermedad coronaria e hipercolesterolemia y 50 individuos sanos. Para establecer diferencias en las frecuencias alélicas entre casos y controles, se utilizó el test de chi cuadrado. Se realizó regresión logística condicionada al analizar cada una de las variables consideradas en el estudio. Los resultados muestran: 1. Las frecuencias de los alelos VNTR mayores de 48 repeticiones fueron significativamente mayores en pacientes con enfermedad coronaria e hipercolesterolemia que en individuos sanos. 2. Las cifras elevadas de triglicéridos, glicemia e hipertensión arterial, contribuyeron significativamente a la manifestación de esta enfermedad. En conclusión, en la muestra analizada los alelos VNTR de mayor tamaño favorecen la aparición de enfermedad coronaria e hipercolesterolemia, pero la contribución de los niveles de glicemia, triglicéridos e hipertensión arterial representan mayor riesgo para la expresión de la patología

DNA polymorphisms of apolipoprotein B and AI-CIII-AIV genes in a Brazilian population: a preliminary report

Possible associations between coronary heart disease (CHD) and restriction fragment length polymorphisms (RFLPs) in the apo AI-CIII-AIV cluster and the apo B gene were investigated in a Brazilian population consisting of 46 patients with CHD and 24 individuals without evidence of CHD. A preliminary genetic analysis of SstI RFLP in the apo AI-CIII-AIV cluster showed a significantly higher frequency of the rare SstI allele (S2) in CHD patients as compared with controls. No significant differences were found in the frequencies of PstI RFLP in the apo AI-CIII-AIV cluster or XbaI and EcoRI RFLPs in the apo B gene between CHD patients and controls. Moreover, no association was seen between the RFLPs studied and myocardial infarction or plasma cholesterol or triglyceride levels.

Analysis of the human apolipoprotein B gene 3 hypervariable region among UAE nationals

With the aim of identifying a multi-marker system for DNA "fingerprinting" in the UAE population, we have explored the potential value of a highly polymorphic marker localised 100 base pairs after the end of the human apolipoprotein B gene. This genetic marker is more polymorphic in the indigenous UAE population than in any other part of the world where it has been studied because of unique patterns of allele distribution. It will therefore be quite useful for population genetic studies, and it can certainly be part of a multi-system for DNA "fingerprinting" in the UAE