Major gene effects on apolipoprotein B concentrations in families of adolescents—Results from a community-based study in Taiwan

Common sequence variants in CD36 gene and the levels of triglyceride and high-density lipoprotein cholesterol among ethnic Chinese in Taiwan

Background

Evidence of the genetic association between CD36 candidate gene and the risk of metabolic syndrome and its components has been inconsistent. This case–control study assessed the haplotype-tagged SNPs from CD36 on the risk of metabolic syndrome and components.

Methods and results

We recruited 1,000 cases and age, gender-matched controls were randomly selected from the participants with metabolic syndrome defined by International Diabetes Federation. Overall, the haplotype tagged SNPs of CD36 gene were not related to the risk of metabolic syndrome. For individuals with normal lipid levels, several SNPs were significantly associated with the triglycerides and HDL-cholesterol levels: Subjects with rs3211848 homozygote had a higher triglyceride level (99.16 ± 2.61 mg/dL), compared with non-carriers (89.27 ± 1.45 mg/dL, P = 0.001). In addition, compared with non-carriers, individuals with rs1054516 heterozygous and homozygous genotypes had a significantly lower HDL-cholesterol (46.6 ± 0.46 mg/dL for non-carrier, 44.6 ± 0.36 mg/dL for heterozygous, and 44.3 ± 0.56 mg/dL for homozygous, P = 0.0008).

Conclusion

The CD36 gene variants were significantly associated with triglycerides and HDL-cholesterol concentrations among ethnic Chinese in Taiwan.

Heritability of serum apolipoprotein concentrations in middle-aged Japanese twins

Background

Studies of the genetic and environmental influences on apolipoproteins have been conducted, but few have used data from Japanese twins. The aim of this study was to quantify and compare the genetic and environmental causes of individual differences in the serum concentrations of apolipoproteins in Japanese middle-aged twins.

Methods

Apo A-I, apo A-II, apo B, apo C-II, apo C-III, and apo E were studied. A total of 142 twin pairs, aged 45 through 65 years, were enrolled: 85 monozygotic pairs (59 male, 26 female) and 57 same-sexed dizygotic pairs (43 male, 14 female). The intraclass correlation coefficient and structural equation modeling were used to estimate the best-fitting model and heritability.

Results

Sixteen percent to 75% of the total variances of apo A-I, apo C-II, and apo C-III were attributable to genetic influence; apo A-I and apo C-II were influenced by dominant genetic factors. Twenty percent to 73% of the total variances of apo A-II, apo B, and apo E were attributable to additive genetic influence; apo B was clearly influenced by common environmental factors. Furthermore, the heritability of all apolipoproteins was higher among females than among males.

Conclusions

Genetic factors, including additive genetic effects (A) and dominant effects (D), influence apolipoprotein levels. However, a common environment does not influence the variances of these apolipoproteins, with the exception of apo B. Furthermore, the heritability of apolipoprotein phenotypes differs by sex.

Sports activity and risk of type 2 diabetes in Chinese

An association between physical inactivity and obesity risk has been established. However, the relationship between sports activity and the risk of diabetes among Chinese populations is still unclear. We prospectively investigated the association between sports activity and incidence of type 2 diabetes in a Chinese population. Habitual physical activity in the presumed last year was obtained from a questionnaire developed by Baecke and colleagues. During a median 9.02-year follow-up period among the 1936 participants with complete questionnaire data, 312 participants developed diabetes. After adjusting for age, gender and body mass index, the relative risk (RR) of diabetes according to quartiles of sports activity were 0.86, 0.71 and 0.72 (95% Confidence Interval [CI], 0.52-0.99, P for trend, 0.048). Participants with the highest quartiles of sports activity had a significantly lower risk than the participants with the lowest quartiles among the obese group (multivariate RR, 0.61, 95% CI, 0.41-0.92, P for trend=0.018). Furthermore, the RRs of diabetes were 2.24 (95% CI, 1.58-3.19) for participants who were obese and sedentary, compared with those who were of a healthy weight and participated actively in sports. The findings suggest a significant inverse association between sports activity and incidence of type 2 diabetes in middle to older-aged Chinese individuals.

Genetic association study of APOA1/C3/A4/A5 gene cluster and haplotypes on triglyceride and HDL cholesterol in a community-based population

BACKGROUND

Polymorphism of apolipoprotein A1/C3/A4/A5 gene cluster affected lipid profiles in general population. We reported 6 polymorphisms, APOA1 -75G>A, APOA1 83C>T, APOC3 3175C>G, APOC3 3206G>T, APOA4 127A>G, and APOA5 553G>T in APOA1/C3/A4/A5 gene and the haplotype structures on triglyceride and HDL traits among ethnic Chinese.

RESULTS

Overall, there were statistically significant differences in the distribution of APOA1 -75G>A and APOA5 +553G>T genotypes comparing cases with control subjects. For the APOA1 -75 SNP, a lower risk of triglyceride/HDL among subjects with A/A genotype compared with those with the G/G genotype (odds ratio, OR=0.39, 95% CI 0.16-0.92, P=0.04). However, the risk magnitude reduced after multivariate adjustments. For continuous traits, we found that only in APOA5 +553 T allele carriers showed a significant higher triglyceride and a significant lower HDL cholesterol level than subjects with APOA5 +553 G/G genotypes. There were significant differences in overall haplotype frequencies between case and control subjects (P<0.001).

CONCLUSION

There is an important role of APOA1/C3/A4/A5 gene polymorphisms and haplotypes in the development of high triglyceride/HDL ratio in Chinese.

Heritability and major gene effects on left ventricular mass in the Chinese population: a family study

Background

Genetic components controlling for echocardiographically determined left ventricular (LV) mass are still unclear in the Chinese population.

Methods

We conducted a family study from the Chin-San community, Taiwan, and a total of 368 families, 1145 subjects, were recruited to undergo echocardiography to measure LV mass. Commingling analysis, familial correlation, and complex segregation analysis were applied to detect component distributions and the mode of inheritance.

Results

The two-component distribution model was the best-fitting model to describe the distribution of LV mass. The highest familial correlation coefficients were mother-son (0.379, P < .0001) and father-son (0.356, P < .0001). Genetic heritability (h²) of LV mass was estimated as 0.268 ± 0.061 (P < .0001); it decreased to 0.153 ± 0.052 (P = .0009) after systolic blood pressure adjustment. Major gene effects with polygenic components were the best-fitting model to explain the inheritance mode of LV mass. The estimated allele frequency of the gene was 0.089.

Conclusion

There were significant familial correlations, heritability and a major gene effect on LV mass in the population-based families.