Variable frequencies of apolipoprotein E genotypes and its effect on serum lipids in the Guangxi Zhuang and Han children

Genetic risks of Alzheimer's by APOE and MAPT on cortical morphology in young healthy adults

Genetic risk factors such as APOE ε4 and MAPT (rs242557) A allele are associated with amyloid and tau pathways and grey matter changes at both early and established stages of Alzheimer's disease, but their effects on cortical morphology in young healthy adults remain unclear. A total of 144 participants aged from 18 to 24 underwent 3T MRI and genotyping for APOE and MAPT to investigate unique impacts of these genetic risk factors in a cohort without significant comorbid conditions such as metabolic and cardiovascular diseases. We segmented the cerebral cortex into 68 regions and calculated the cortical area, thickness, curvature and folding index for each region. Then, we trained machine learning models to classify APOE and MAPT genotypes using these morphological features. In addition, we applied a growing hierarchical self-organizing maps algorithm, which clustered the 68 regions into 4 subgroups representing different morphological patterns. Then, we performed general linear model analyses to estimate the interaction between APOE and MAPT on cortical patterns. We found that the classifiers using all cortical features could accurately classify individuals carrying genetic risks of dementia outperforming each individual feature alone. APOE ε4 carriers had a more convoluted and thinner cortex across the cerebral cortex. A similar pattern was found in MAPT A allele carriers only in the regions that are vulnerable for early tau pathology. With the clustering analysis, we found a synergetic effect between APOE ε4 and MAPT A allele, i.e. carriers of both risk factors showed the most deviation of cortical pattern from the typical pattern of that cluster. Genetic risk factors of dementia by APOE ε4 and MAPT (rs242557) A allele were associated with variations of cortical morphology, which can be observed in young healthy adults more than 30 years before Alzheimer's pathology is likely to occur and 50 years before dementia symptoms may begin.

Apolipoprotein E Gene Polymorphism, Serum Lipids, and Risk of Superficial Fungal Infections in Egyptian Patients - A Preliminary Case-Controlled Study

Background

Apolipoprotein E (APOE) gene isoforms have been found to affect the risk of superficial fungal infections (SFIs). However, the data only cover a few ethnicities.

Aims

The present work intended to investigate the association of APOE gene polymorphism and serum lipids with the susceptibility of SFIs among a group of Egyptian patients.

Materials and Methods

Standard laboratory methods were used to estimate the serum lipid profile, and polymerase chain reaction-restriction fragment length polymorphism was used to detect APOE gene polymorphism in deoxyribonucleic acid extracted from 150 SFI patients and an equal number of apparently healthy matched controls.

Results

Serum total cholesterol, triglycerides, and low-density lipoprotein cholesterol were significantly higher in the studied patients than in controls. The APOE gene ε2, ε4 alleles, and ε3/4 and ε3/2 genotypes were significantly distributed in the patients than in the controls. APOE ε3/3 genotype was predominant in dermatophytosis and tinea versicolour patients, and ε3/4 genotype was predominant in candidiasis.

Conclusions

ApoE alleles ε2 and ε4, and genotypes ε2/3 and ε3/4 are linked to SFI and may be risk factors, whereas allele ε3 and genotype ε3/3 may be protective for SFI in the Egyptian population studied. The lipid profile results suggest that hyperlipidemia may provide evidence for SFI pathogenesis. However; further large-scale studies are still needed to validate our results.

Genetic Regulatory Networks of Apolipoproteins and Associated Medical Risks

Apolipoproteins (APO proteins) are the lipoprotein family proteins that play key roles in transporting lipoproteins all over the body. There are nearly more than twenty members reported in the APO protein family, among which the A, B, C, E, and L play major roles in contributing genetic risks to several disorders. Among these genetic risks, the single nucleotide polymorphisms (SNPs), involving the variation of single nucleotide base pairs, and their contributing polymorphisms play crucial roles in the apolipoprotein family and its concordant disease heterogeneity that have predominantly recurred through the years. In this review, we have contributed a handful of information on such genetic polymorphisms that include APOE, ApoA1/B ratio, and A1/C3/A4/A5 gene cluster-based population genetic studies carried throughout the world, to elaborately discuss the effects of various genetic polymorphisms in imparting various medical conditions, such as obesity, cardiovascular, stroke, Alzheimer's disease, diabetes, vascular complications, and other associated risks.

Serum apolipoprotein E concentration and polymorphism influence serum lipid levels in Chinese Shandong Han population

Apolipoprotein E (ApoE), which has been shown to influence serum lipid parameters, can bind to multiple types of lipids and plays an important role in the metabolism and homeostasis of lipids and lipoproteins. A previous study showed that ApoE concentration significantly affects serum lipid levels independently of ApoE polymorphism. The serum lipid levels were also closely correlated with dietary habits, and Shandong cuisine is famous for its high salt and oil contents, which widely differ among the different areas in China. Therefore, studying the effect of ApoE polymorphism on ApoE concentration and serum lipid levels in Shandong province is very important.A total of 815 subjects including 285 men and 530 women were randomly selected and studied from Jinan, Shandong province. In order to evaluate the association of ApoE polymorphism and serum level on lipid profiles, the ApoE genotypes, as well as levels of fasting serum ApoE and other lipid parameters, were detected in all subjects.The frequency of the ApoE E3 allele was highest (83.1%), while those of E2 and E4 were 9.4% and 7.5%, respectively, which are similar to those in other Asian populations. ApoE2 allele carriers showed significantly increased ApoE levels but lower levels of serum total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and Apolipoprotein B (ApoB).We found that ApoE level is influenced by ApoE polymorphism in a gene-dependent manner. The ApoE polymorphism showed different influences on serum lipid parameters with increasing age and body mass index (BMI) in our Shandong Han population.

Association of apolipoprotein E polymorphism with plasma lipid disorders, independent of obesity-related traits in Vietnamese children

Background

The dyslipidemia associated with obesity plays a major role in the development of atherosclerosis and cardiovascular disease. Dyslipidemia in childhood can progress in adult stage. APOE is one of the most important genes that regulate plasma lipid transport and clearance. The study aimed to assess whether the common APOE polymorphism is associated with lipid profiles and dyslipidemia, and it could be modulated by obesity-related traits (body mass index, waist circumference, hip circumference, and waist-to-hip ratio) in Vietnamese children.

Methods

A case-control study was designed including 249 cases with dyslipidemia and 600 controls without dyslipidemia. Dyslipidemia is defined as elevated total or low-density lipoprotein (LDL) cholesterol levels, or low levels of high-density lipoprotein (HDL) cholesterol. Genotype for APOE polymorphism (rs7412 and rs429358) was determined by the polymerase chain reaction and restriction fragment length polymorphism method. The association of APOE genotypes with plasma lipid disorders was tested by binary logistic regression analysis, taking into account the confounding factors of age, sex, residence, province and obesity-related traits.

Results

In comparison with ε3/ε3 carriers, the ε4 carriers had the highest concentration of serum TC and LDL-C in cases and controls (P ≤ 0.001), while ε2 carriers had the lowest. Carriers without TT haplotype had higher serum TC than those with TT haplotype. The ε4 carriers had higher hypoalphalipoproteinemia risk than ε3/ε3 carriers (OR = 2.78, P = 0.02) before and after adjustment for age, gender, residence and obesity-related traits.

Conclusions

The study suggested that the APOE genotype and haplotype significantly associated with plasma TC and LDL-C level in Vietnamese children. The association of APOE genotype with hypoalphalipoproteinemia was independent of obesity-related traits.

Electronic supplementary material

The online version of this article (doi:10.1186/s12944-016-0349-6) contains supplementary material, which is available to authorized users.

Genetic Contribution of Variants near SORT1 and APOE on LDL Cholesterol Independent of Obesity in Children

Objective

To assess potential effects of variants in six lipid modulating genes (SORT1, HMGCR, MLXIPL, FADS2, APOE and MAFB) on early development of dyslipidemia independent of the degree of obesity in children, we investigated their association with total (TC), low density lipoprotein (LDL-C), high density lipoprotein (HDL-C) cholesterol and triglyceride (TG) levels in 594 children. Furthermore, we evaluated the expression profile of the candidate genes during human adipocyte differentiation.

Results

Expression of selected genes increased 10¹ to >10⁴ fold during human adipocyte differentiation, suggesting a potential link with adipogenesis. In genetic association studies adjusted for age, BMI SDS and sex, we identified significant associations for rs599839 near SORT1 with TC and LDL-C and for rs4420638 near APOE with TC and LDL-C. We performed Bayesian modelling of the combined lipid phenotype of HDL-C, LDL-C and TG to identify potentially causal polygenic effects on this multi-dimensional phenotype and considering obesity, age and sex as a-priori modulating factors. This analysis confirmed that rs599839 and rs4420638 affect LDL-C.

Conclusion

We show that lipid modulating genes are dynamically regulated during adipogenesis and that variants near SORT1 and APOE influence lipid levels independent of obesity in children. Bayesian modelling suggests causal effects of these variants.

Rapid identification of apolipoprotein E genotypes by high-resolution melting analysis in Chinese Han and African Fang populations

Apolipoprotein E (APOE) gene polymorphism can affect APOE gene transcription, serum lipid levels and repair of tissue damage, which could place individuals at serious risk of cardiovascular disease or certain infectious diseases. Recently, high-resolution melting (HRM) analysis was reported to be a simple, inexpensive, accurate and sensitive method for the genotyping or/and scanning of rare mutations. For this reason, an HRM analysis was used in the present study for APOE genotyping in the Southern Chinese Han and African Fang populations. A total of 100 healthy Southern Chinese Han and 175 healthy African Fang individuals attended the study. Polymerase chain reaction-DNA sequencing was used as a reference method for the genotyping of these samples. The six APOE genotypes could all be rapidly and efficiently identified by HRM analysis, and 100% concordance was found between the HRM analysis and the reference method. The allele frequencies of APOE in the Southern Chinese Han population were 7.0, 87.5 and 5.5% for ɛ2, ɛ3 and ɛ4, respectively. In the African Fang population, the allele frequencies of APOE were 24.3, 65.7 and 10.0% for ɛ2, ɛ3 and ɛ4, respectively. A statistically significant difference was found between the allele frequencies between the populations (P<0.05). In conclusion, the present study revealed the molecular characterization of APOE gene polymorphism in the Han population from the Chaozhou region of Southern China and the Fang population from Equatorial Guinea. The findings of the study indicated that HRM analysis could be used as an accurate and sensitive method for the rapid screening and identification of APOE genotypes in prospective clinical and population genetic analyses.

Apolipoprotein E gene polymorphism and serum lipid profile in Saudi patients with psoriasis

Background/Aim. Apolipoprotein E (APOE) gene variants have been reported to influence psoriasis risk. However, data is limited to a few ethnicities and no similar study has been performed in middle eastern populations. We investigated this association in Saudi psoriasis patients. Methods. Saudi subjects (294) were genotyped for APOE gene using APOE StripAssay kit. Results. The frequencies of alleles ε2, ε4, and genotypes ε3/ε4 and ε3/ε2 were significantly higher in psoriasis patients compared with those in controls. The frequency of ε3 allele and ε3/ε3 genotype was significantly lower in patients. Other genotypes, ε2/ε4, ε2/ε2, and ε4/ε4, were absent in both groups. The serum cholesterol, triglycerides, and LDL levels were significantly higher in psoriasis patients contrary to HDL level. Patients with APOE ε4 had significantly higher levels of total cholesterol and LDL cholesterol, whereas those with the ε2 had higher HDL cholesterol, and triglycerides. Conclusion. APOE alleles ε2, ε4, and genotypes ε2/ε3 and ε4/ε3 are associated with psoriasis and can be a risk factor while allele ε3 and genotype ε3/ε3 may be protective for psoriasis in Saudis. Results of lipid profile support that psoriasis is one of the independent risk factors for hyperlipidemia and emphasize the need of screening cardiovascular diseases in psoriatic patients.