Marked Differences of Haplotype Tagging SNP Distribution, Linkage, and Haplotype Profile of APOA5 Gene in Roma Population Samples

Association of rs662799 variant and APOA5 gene haplotypes with metabolic syndrome and its components: a meta-analysis in North Africa

Apolipoprotein A5 (APOA5) has been linked to metabolic syndrome (MetS) in several populations. In North Africa, only the Tunisian and Moroccan populations were investigated. Our aim is to assess the association between APOA5 gene variant (rs662799) and haplotypes with MetS in Tunisian population and to perform a meta-analysis in North Africa. A total of 594 Tunisian participants were genotyped for polymorphism rs662799 using KASPar technology. Two polymorphisms rs3135506 and rs651821 in APOA5 gene genotyped in our previous study, were used in addition to rs662799 to assess the haplotype association with MetS. The genotype of 875 participants was used for the meta-analysis. Statistical analyses were performed with R software.

The rs662799 increases the risk of MetS under the dominant (P=0.018) and the additive models (P=0.028) in the Tunisian population. After stratification of the cohort following the sex and the geographic origin, a positive association of rs662799 with MetS was found for participant from the Northern region and for the women group. Only the haplotype AGT showed a significant association with MetS by decreasing the risk of the disease.

The meta-analysis reported a significant association of rs662799 and rs3135506 with MetS.

Our results showed a significant association between the APOA5 gene variants rs662799 and haplotypes with MetS and its traits in Tunisia. An impact of the sex and the geographic origin on the genotype distribution was highlighted. Our funding emphasizes the role of APOA5 in the development of MetS in North Africa.

Alcohol, Carbohydrate, and Calcium Intakes and Smoking Interactions with APOA5 rs662799 and rs2266788 were Associated with Elevated Plasma Triglyceride Concentrations in a Cross-Sectional Study of Korean Adults

BACKGROUND

Plasma triglyceride (TG) concentrations are markedly higher among Asians, which may be associated with the interaction of genetics and lifestyle factors.

OBJECTIVE

The purpose of this study was to investigate the genetic variants that have a strong association with plasma TG concentrations from genome-wide association study and to identify lifestyle interactions with the genetic variants that are associated with dyslipidemia in a cohort of Korean adults.

DESIGN

Korean genome and epidemiology study utilized a cross-sectional design of Koreans to determine genetic variants and lifestyle factors, including nutrient intakes, in a retrospective hospital-based city cohort conducted by the Korean Center for Disease and Control during 2004-2013.

PARTICIPANTS

Korean adults aged 40 to 77 years were participants (n=28,445).

MAIN OUTCOME MEASURES

The genetic variants that influence plasma TG concentrations were selected by genome-wide association study using an allele genetic model after adjusting for age, sex, area of residence, and body mass index. Lipid profiles and nutrient intakes from food frequency questionnaires were measured. The interactions between the single nucleotide polymorphisms and lifestyle factors were determined to influence plasma TG levels.

RESULTS

Carrying the minor alleles of APOA5 rs662799 and rs2266788 had an association with higher plasma TG concentrations by 1.86- and 1.51-fold, respectively, compared with those with the major allele (P=8.89E-150 and P=4.75E-68, respectively). Sex had an interaction with these single nucleotide polymorphisms, with males having higher plasma TG concentrations. The single nucleotide polymorphisms had significant interactions with carbohydrate, fat, and calcium intakes; alcohol consumption; and smoking status that were associated with plasma TG concentrations. Carriers with the minor allele of each single nucleotide polymorphisms had higher plasma TG concentrations when consuming-low fat (<15%) and high carbohydrate (≥72%) diets than those with major alleles. Carriers of the minor alleles with low calcium intakes (<500 mg/day) experienced elevated plasma TG concentrations compared with carriers of the major alleles. Smokers and alcohol drinkers with either of the minor alleles of APOA5, rs662799 or rs2266788, had higher plasma TG concentrations than those with its major allele.

CONCLUSIONS

These results indicated that carrying the minor alleles of APOA5 rs662799 and rs2266788, especially for men, was associated with elevated TG concentrations and suggested that Korean carriers of the minor alleles could be at increased risk of hypertriglyceridemia. Further research is needed to investigate the efficacy of modulating lifestyle factors to prevent dyslipidemia in people carrying the minor alleles of APOA5 rs662799 and rs2266788.

Distribution of ADH1B genotypes predisposed to enhanced alcohol consumption in the Czech Roma/Gypsy population

OBJECTIVE

The aim of the study was to analyse the frequencies of rs1229984 genotypes within the alcohol dehydrogenase (ADH1B) gene in a Gypsies/Roma population and compare them with other populations and with ethanol consumption.

METHODS

We analysed the ADH1B (rs1229984; Arg47→His; c.143G>A) genotype using the Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) in two ethnically different groups - Gypsies/Roma (N = 301) and Czechs (N = 300) where one day alcohol consumption was recorded.

RESULTS

ADH1B genotype/allelic frequencies did not significantly differ between the populations (p = 0.32). The frequency of minor A allele carriers was slightly higher in Gypsies/Roma (14.7%) than in Czechs (11.9%). The prevalence of subjects reporting alcohol intake on the previous day was non-significantly lower in Gypsies/Roma (10.5% vs. 16.4%), as was the amount of alcohol consumed the day before the examination in ethanol consumers (36.1 ± 18.3 g vs. 43.0 ± 27.2 g).

CONCLUSIONS

The frequency of rs1229984 genotypes in the ADH1B gene within the Gypsies/Roma population corresponds with frequencies obtained in North India/Central Asia, the putative country of this ethnic origin. Our results suggest that the minority Gypsies/Roma population consume slightly less alcohol than the Czech majority population.

Generalizability and applicability of results obtained from populations of European descent regarding the effect direction and size of HDL-C level-associated genetic variants to the Hungarian general and Roma populations

OBJECTIVES

Large-scale association studies that mainly involve European populations identified many genetic loci related to high-density lipoprotein cholesterol (HDL-C) levels, one of the most important indicators of the risk for cardiovascular diseases. The question with intense speculation of whether the effect estimates obtained from European populations for different HDL-C level-related SNPs are applicable to the Roma ethnicity, the largest minority group in Europe with a South Asian origin, was addressed in the present study.

DESIGN

The associations between 21 SNPs (in the genes LIPC(G), CETP, GALNT2, HMGCP, ABCA1, KCTD10 and WWOX) and HDL-C levels were examined separately in adults of the Hungarian general (N = 1542) and Roma (N = 646) populations by linear regression. Individual effects (direction and size) of single SNPs on HDL-C levels were computed and compared between the study groups and with data published in the literature.

RESULTS

Significant associations between SNPs and HDL-C levels were more frequently found in general subjects than in Roma subjects (11 SNPs in general vs. 4 SNPs in Roma). The CETP gene variants rs1532624, rs708272 and rs7499892 consistently showed significant associations with HDL-C levels across the study groups (p ˂ 0.05), indicating a possible causal variant(s) in this region. Although nominally significant differences in effect size were found for three SNPs (rs693 in gene APOB, rs9989419 in gene CETP, and rs2548861 in gene WWOX) by comparing the general and Roma populations, most of these SNPs did not have a significant effect on HDL-C levels. The β coefficients for SNPs in the Roma population were found to be identical both in direction and magnitude to the effect obtained previously in large-scale studies on European populations.

CONCLUSIONS

The effect of the vast majority of the SNPs on HDL-C levels could be replicated in the Hungarian general and Roma populations, which indicates that the effect size measurements obtained from the literature can be used for risk estimation for both populations.

Sequence Analysis of APOA5 Among the Kuwaiti Population Identifies Association of rs2072560, rs2266788, and rs662799 With TG and VLDL Levels

Common variants of Apolipoprotein A5 (APOA5) have been associated with lipid levels yet very few studies have reported full sequence data from various ethnic groups. The purpose of this study was to analyse the full APOA5 gene sequence to identify variants in 100 healthy Kuwaitis of Arab ethnicities and assess their association with variation in lipid levels in a cohort of 733 samples. Sanger method was used in the direct sequencing of the full 3.7 Kb APOA5 and multiple sequence alignment was used to identify variants. The complete APOA5 sequence in Kuwaiti Arabs has been deposited in GenBank (KJ401315). A total of 20 reported single nucleotide polymorphisms (SNPs) were identified. Two novel SNPs were also identified: a synonymous 2197G>A polymorphism at genomic position 116661525 and a 3′ UTR 3222 C>T polymorphism at genomic position 116660500 based on human genome assembly GRCh37/hg:19. Five SNPs along with the two novel SNPs were selected for validation in the cohort. Association of those SNPs with lipid levels was tested and minor alleles of three SNPs (rs2072560, rs2266788, and rs662799) were found significantly associated with TG and VLDL levels. This is the first study to report the full APOA5 sequence and SNPs in an Arab ethnic group. Analysis of the variants identified and comparison to other populations suggests a distinctive genetic component in Arabs. The positive association observed for rs2072560 and rs2266788 with TG and VLDL levels confirms their role in lipid metabolism.