Impact of adiponectin gene polymorphisms on plasma lipoprotein and adiponectin concentrations of viscerally obese men

Quantile-dependent expressivity of plasma adiponectin concentrations may explain its sex-specific heritability, gene-environment interactions, and genotype-specific response to postprandial lipemia

Background

"Quantile-dependent expressivity" occurs when the effect size of a genetic variant depends upon whether the phenotype (e.g. adiponectin) is high or low relative to its distribution. We have previously shown that the heritability (h² ) of adiposity, lipoproteins, postprandial lipemia, pulmonary function, and coffee and alcohol consumption are quantile-specific. Whether adiponectin heritability is quantile specific remains to be determined.

Methods

Plasma adiponectin concentrations from 4,182 offspring-parent pairs and 1,662 sibships from the Framingham Heart Study were analyzed. Quantile-specific heritability from offspring-parent (β _OP,h² = 2β _OP/(1 + r_spouse)) and full-sib regression slopes (β _FS, h² = {(1 + 8r_spouse β _FS)^0.05-1}/(2r_spouse)) were robustly estimated by quantile regression with nonparametric significance assigned from 1,000 bootstrap samples.

Results

Quantile-specific h² (± SE) increased with increasing percentiles of the offspring's age- and sex-adjusted adiponectin distribution when estimated from β _OP (P _trend = 2.2 × 10^-6): 0.30 ± 0.03 at the 10th, 0.33 ± 0.04 at the 25th, 0.43 ± 0.04 at the 50th, 0.55 ± 0.05 at the 75th, and 0.57 ± 0.08 at the 90th percentile, and when estimated from β _FS (P _trend = 7.6 × 10^-7): 0.42 ± 0.03 at the 10th, 0.44 ± 0.04 at the 25th, 0.56 ± 0.05 at the 50th, 0.73 ± 0.08 at the 75th, and 0.79 ± 0.11 at the 90th percentile. Consistent with quantile-dependent expressivity, adiponectin's: (1) heritability was greater in women in accordance with their higher adiponection concentrations; (2) relationships to ADIPOQ polymorphisms were modified by adiposity in accordance with its adiponectin-lowering effect; (3) response to rosiglitazone was predicted by the 45T> G ADIPOQ polymorphism; (4) difference by ADIPOQ haplotypes increased linearly with increasing postprandial adiponectin concentrations.

Conclusion

Adiponectin heritability is quantile dependent, which may explain sex-specific heritability, gene-environment and gene-drug interactions, and postprandial response by haplotypes.

Genetic association of ADIPOQ gene variants (-3971A>G and +276G>T) with obesity and metabolic syndrome in North Indian Punjabi population

BACKGROUND AND AIMS

At present obesity and metabolic syndrome (MetS) in India are the most challenging health problems. It is also well accepted that obesity is a significant risk factor for the development of metabolic syndrome and other degenerative diseases. Many studies have reported that single-nucleotide polymorphisms (SNPs) of the adiponectin (ADIPOQ) gene have been associated with obesity and its related disorders. Here, we aimed to investigate the association of two intronic variants in ADIPOQ gene, -3971A>G (rs822396) and +276G>T (rs1501299) with obesity and metabolic syndrome.

METHODS

Biochemical and anthropometric measurements were obtained from a total of 550 unrelated subjects (obese = 250 and non-obese = 300) of North Indian Punjabi population. Genotyping for the intron variants were performed by polymerase chain reaction based restriction fragment length polymorphism (PCR-RFLP) methods. After genotyping, as a quality control measure 10% of the samples for each polymorphism were confirmed by Sanger Sequencing method. The distributions of genotypic and allelic frequencies among obese and non-obese groups were compared by chi-square test and the corresponding risk was calculated using binary logistic regression. The effects of multiple testing were controlled by applying Bonferroni corrections.

RESULTS

All the anthropometric and biochemical parameters except triglycerides (TG) and very low-density lipoproteins cholesterol (VLDL-C) have shown significant association with both GG and TT genotypes of -3971A>G (rs822396) and +276G>T (rs1501299) polymorphisms respectively. The frequencies of GG (-3971A>G) and TT (+276G>T) genotypes were higher among obese cases (p = 0.008 and p = 0.035 respectively). However, no significant association was found between allelic frequencies of ADIPOQ rs822396 and obesity, whereas the association of ADIPOQ rs1501299 attenuated and became marginally significant after Bonferroni correction (p>0.025). Both the variant genotypes of ADIPOQ gene polymorphisms (-3971GG and +276TT) significantly increased the risk of development of obesity (OR: 1.52, p = 0.03; OR: 1.58, p = 0.04 respectively) and MetS (OR: 1.42, p = 0.03; OR: 1.57, p = 0.01 respectively) in the present population, after adjusting the various covariates. The G-T haplotype model (possessing -3971G and +276T alleles) was shown toprovide ~ 3 fold risk towards the obesity susceptibility (OR: 2.69, p = 0.009) and MetS risk (OR: 2.73, p = 0.009) and the association persisted after adjusting for different confounding variables.

CONCLUSION

The present study has confirmed that ADIPOQ -3971A>G (rs822396) and +276G>T (rs1501299) polymorphism may be clinically helpful to estimate obesity and MetS risk in North Indian Punjabi population.

Association of two Common Single Nucleotide Polymorphisms (+45T/G and +276G/T) of ADIPOQ Gene with Coronary Artery Disease in Type 2 Diabetic Patients

Background:

Adiponectin, an adipocyte-secreted hormone, is known to have anti-atherogenic, anti-inflammatory, and anti-diabetic properties. In the present study, the association between two common single nucleotide polymorphisms (SNPs) (+45T/G and +276G/T) of ADIOPQ gene and coronary artery disease (CAD) was assessed in the subjects with type 2 diabetes (T2DM).

Methods:

Genotypes of two SNPs were determined by polymerase chain reaction-restriction fragment length polymorphism in 200 subjects with T2DM (100 subjects with CAD and 100 without CAD).

Results:

The frequency of TT genotype of +276G/T was significantly elevated in CAD compared to controls (χ²=7.967, P=0.019). A similar difference was found in the allele frequency of +276G/T between two groups (χ²=3.895, P=0.048). The increased risk of CAD was associated with +276 TT genotype when compared to reference GG genotype (OR=5.158; 95% CI=1.016-26.182, P=0.048). However, no similar difference was found in genotype and allele frequencies of SNP +45T/G between two groups. There was a CAD protective haplotype combination of +276 wild-type and +45 mutant-type allele (276G-45G) (OR=0.37, 95% CI=0.16-0.86, P=0.022) in the subject population.

Conclusion:

Our findings indicated that T allele of SNP +276G/T is more associated with the increased risk of CAD in subjects with T2DM. Also, a haplotype combination of +45G/+276G of these two SNPs has a protective effect on the risk of CAD.

Prevalence, Risk Factors, and Genetic Traits in Metabolically Healthy and Unhealthy Obese Individuals

Objective. To assess prevalence of metabolically healthy individuals among patients with abdominal obesity (AO) and to determine phenotype and potential genetic traits associated with a benign metabolic status. Methods. 503 AO patients without cardiovascular diseases were examined. Waist circumference (WC), BMI, blood pressure, plasma glucose and serum insulin levels, HOMA-IR, lipid profile, and adiponectin (AN) and leptin (LEP) concentrations in serum were measured. Polymorphisms A19G and Q223R of the LEP and LEP receptor gene, and G276T and T45G of the AN gene were investigated. Results. 91.3% of patients were metabolically unhealthy obese (MUO), and 8.7% metabolically healthy obese (MHO). MHO patients were younger, and had lesser BMI and WC, while duration of obesity, frequency, and duration of physical training were greater than MUO patients (p < 0.05). In MHO and MUO patients distribution of the G19G, G19A, and A19A genotypes of the LEP gene and G276G, G276T, and T276T genotypes of AN gene did not differ. The Т45Т genotype was associated with increase of metabolic disorders' risk for patients with АО (OR = 2.331; 95%  CI = 1.121 ÷ 5.132). Conclusions. Prevalence of MHO individuals among patients with AO is low. Benign metabolic status was associated with younger age, lower waist circumference, and higher physical activity, shorter duration of obesity, and G45G adiponectin genotype carriage.

Genetic basis of interindividual susceptibility to cancer cachexia: selection of potential candidate gene polymorphisms for association studies

Cancer cachexia is a complex and multifactorial disease. Evolving definitions highlight the fact that a diverse range of biological processes contribute to cancer cachexia. Part of the variation in who will and who will not develop cancer cachexia may be genetically determined. As new definitions, classifications and biological targets continue to evolve, there is a need for reappraisal of the literature for future candidate association studies. This review summarizes genes identified or implicated as well as putative candidate genes contributing to cachexia, identified through diverse technology platforms and model systems to further guide association studies. A systematic search covering 1986-2012 was performed for potential candidate genes / genetic polymorphisms relating to cancer cachexia. All candidate genes were reviewed for functional polymorphisms or clinically significant polymorphisms associated with cachexia using the OMIM and GeneRIF databases. Pathway analysis software was used to reveal possible network associations between genes. Functionality of SNPs/genes was explored based on published literature, algorithms for detecting putative deleterious SNPs and interrogating the database for expression of quantitative trait loci (eQTLs). A total of 154 genes associated with cancer cachexia were identified and explored for functional polymorphisms. Of these 154 genes, 119 had a combined total of 281 polymorphisms with functional and/or clinical significance in terms of cachexia associated with them. Of these, 80 polymorphisms (in 51 genes) were replicated in more than one study with 24 polymorphisms found to influence two or more hallmarks of cachexia (i.e., inflammation, loss of fat mass and/or lean mass and reduced survival). Selection of candidate genes and polymorphisms is a key element of multigene study design. The present study provides a contemporary basis to select genes and/or polymorphisms for further association studies in cancer cachexia, and to develop their potential as susceptibility biomarkers of cachexia.

Association of adiponectin (ADIPOQ) rs2241766 polymorphism and dyslipidemia in HIV/HCV-coinfected patients

BACKGROUND

The adiponectin (ADIPOQ) rs2241766 polymorphism is related to metabolic abnormalities. The aim of this study was to evaluate the association of the ADIPOQ rs2241766 polymorphism with serum dyslipidemia and insulin resistance (IR) in human immunodeficiency virus (HIV)/hepatitis C virus (HCV)-coinfected patients.

METHODS

We carried out a cross-sectional study on 262 patients. ADIPOQ rs2241766 polymorphisms were genotyped by GoldenGate® assay. Generalized linear models (GLMs) were used to compare continuous outcome variables (total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), non-HDL-C and homeostatic model assessment (HOMA)) and categorical outcome variables (TC≥200 mg/dL, TG≥170 mg/dL, LDL-C≥100 mg/dL, HDL-C≤35 mg/dL, non-HDL-C≥120 mg/dL and HOMA≥3·8) according to ADIPOQ genotype under a dominant inheritance model.

RESULTS

Patients with the rs2241766 GG/GT genotype had significantly lower serum TC levels (P=0·038) and percentages of TC≥200 mg/dL (P=0·022) than rs2241766 TT carriers. When adjusted GLM was performed, rs2241766 GG/GT was associated with low serum TC levels (arithmetic mean ratio (AMR)=0·92 [(95% CI=0·85; 0·99) P=0·024]) and low likelihood of TC≥200 mg/dL (odds ratio (OR)=0·32 [(95% CI=0·11; 0·88) P=0·027]. When stratifying by steatosis, no significant values were found for patients without steatosis. However, for patients with steatosis, rs2241766 GG/GT genotypes were related to low TC serum values of TC (AMR=0·89; P=0·027), LDL-C (AMR=0·85; P=0·039) and non-HDL-C (AMR=0·86; P=0·015). No significant associations were found between rs2241766 and HOMA values.

CONCLUSIONS

The presence of the ADIPOQ rs2241766 G allele (GG/GT genotype) was associated with a protective effect against dyslipidemia, primarily in HIV/HCV-coinfected patients with steatosis.

Associations between two single nucleotide polymorphisms of the adiponectin gene, its circulating concentrations and cardiometabolic risk factors in prepubertal children with and without abdominal obesity

BACKGROUND

The adiponectin gene has been identified as a susceptibility locus for metabolic syndrome, diabetes and cardiovascular disease.

AIM

To examine the influence of two single nucleotide polymorphisms (SNPs) of this gene (+276G>T and +45T>G) on circulating adiponectin concentrations, and to evaluate their relationship with adiposity and cardiometabolic risk factors in prepubertal children with and without abdominal obesity.

MATERIAL AND METHODS

168 children (78M, 6-10 yr) were examined, divided into three groups based on waist circumference (WC). Auxological and biochemical parameters were measured by standard procedures. Adiponectin SNPs were genotyped using TaqMan allelic discrimination assays.

RESULTS

Adiponectin concentration correlated inversely with measures of adiposity (rBMIz-score=-0.211, pBMIz-score=0.007; rwc=-0.210, pwc=0.008; rwc/height=-0.215, pwc/height=0.006), and was significantly influenced by blood glucose, insulin and systolic blood pressure (SBP). The +276T-allele carriers had higher SBP and diastolic BP compared to GG-homozygotes (p<0.05), and expressed higher obesity-related measures and lower adiponectin concentrations. As to the +45T>G SNP, the GGsubject had higher total cholesterol and LDL-C concentrations compared to the T-allele carriers (p<0.05), showing worse obesity measures, higher triglyceride, glucose and insulin and lower serum adiponectin values.

CONCLUSION

Genetic variants of the adiponectin gene had an impact on adiposity, adiponectin concentrations and some cardiometabolic variables among prepubertal children.

Genetic association of adiponectin gene polymorphisms (+45T/G and +10211T/G) with type 2 diabetes in North Indians

Adiponectin (ADIPOQ) is an abundant protein hormone which belongs to a family of so-called adipokines. It is expressed mostly by adipocytes and is an important regulator of lipid and glucose metabolism. It was shown that decreased serum adiponectin concentration indicated insulin resistance and type 2 diabetes (T2DM) with the risk of cardiovascular complications. The fact that adiponectin is an insulin-sensitizing hormone with anti-diabetic, anti-inflammatory and anti-atherogenic properties, we proposed to study the association of ADIPOQ gene polymorphisms in subjects with T2DM. DNA was isolated from venous blood samples, quantified and subjected to Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) using suitable primers and restriction endonucleases. Adiponectin levels were measured in serum using ELISA. The genotypic, allelic and carriage rate frequencies distribution in patients and controls were analyzed by PSAW software (ver. 17.0). Odd ratios (OR) with 95% confidence interval (CI) were determined to describe the strength of association by logistic regression model. Out of the two polymorphisms studied, +10211T/G showed significant association (P=0.042), the 'G' allele association being highly significant (P=0.022). Further analysis showed that individuals with 'GG' haplotype were at increased risk of T2DM up to 15.5 times [P=0.015, OR (95% CI); 15.558 (1.690-143.174)]. The present study showed that the 'G' allele of ADIPOQ gene (+10211T/G) plays a prominent role with respect to T2DM susceptibility in North-Indian population.

Effect of interaction between PPARG, PPARA and ADIPOQ gene variants and dietary fatty acids on plasma lipid profile and adiponectin concentration in a large intervention study

Unsaturated fatty acids are ligands of PPAR-γ, which up-regulates genes involved in fatty acid transport and TAG synthesis and the insulin-sensitising adipokine adiponectin, which activates fatty acid β-oxidation via PPAR-α action in liver. We investigated the effect of dietary fatty acid interaction with PPARG, PPARA and ADIPOQ gene variants on plasma lipid and adiponectin concentrations in the Reading Imperial Surrey Cambridge King's study, a five-centre, parallel design, randomised controlled trial of 466 subjects at increased cardiometabolic risk. After a 4-week run-in to baseline, SFA was replaced by MUFA or carbohydrate (low fat) in isoenergetic diets for 24 weeks. Habitual dietary PUFA:SFA ratio×PPARG Pro12Ala genotype interaction influenced plasma total cholesterol (P=0·02), LDL-cholesterol (P=0·002) and TAG (P=0·02) concentrations in White subjects. PPARA Val162Leu×PPARG Pro12Ala genotype interaction influenced total cholesterol (P=0·04) and TAG (P=0·03) concentrations at baseline. After high-MUFA and low-fat diets, total cholesterol and LDL-cholesterol were reduced (P<0·001) and gene×gene interaction determined LDL-cholesterol (P=0·003) and small dense LDL as a proportion of LDL (P=0·012). At baseline, ADIPOQ -10066 G/A A-allele was associated with lower serum adiponectin (n 360; P=0·03) in White subjects. After the high-MUFA diet, serum adiponectin increased in GG subjects and decreased in A-allele carriers (P=0·006 for difference). In GG, adiponectin increased with age after the high MUFA and decreased after the low-fat diet (P=0·003 for difference at 60 years). In conclusion, in Whites, high dietary PUFA:SFA would help to reduce plasma cholesterol and TAG in PPARG Ala12 carriers. In ADIPOQ -10066 GG homozygotes, a high-MUFA diet may help to increase adiponectin with advancing age.

The adiponectin gene, ADIPOQ, and genetic susceptibility to colon cancer

In order to evaluate the contribution of polymorphisms of the adiponectin gene, ADIPOQ, to the risk of colon cancer, we conducted a case-control study of 60 colon cancer patients and 60 age, gender and ethnicity-matched controls in the Saudi population. We tested the hypothesis by analyzing the genotypes for two single nucleotide polymorphisms (SNPs), rs1501299 (G276T) and rs2241766 (T45G), in the ADIPOQ gene. In addition, the study was also designed to assess whether the two SNPs contribute to circulating adiponectin levels. We observed an increased risk of colon cancer associated with the 276T allele. The odds ratio (OR) was 2.64 [95% confidence interval (CI), 0.49-14.6]. The G allele at the T45G polymorphism was associated with a lower risk of colon cancer (OR=0.41; 95% CI, 0.19-0.86). Our results suggest that the risk of developing colon cancer may be partially explained by genetic polymorphisms in the ADIPOQ gene.

ADIPOQ, ADIPOR1, and ADIPOR2 polymorphisms in relation to serum adiponectin levels and BMI in black and white women

Adiponectin is an adipose-secreted protein with influence on several physiologic pathways including those related to insulin sensitivity, inflammation, and atherogenesis. Adiponectin levels are highly heritable and several single-nucleotide polymorphisms (SNPs) in adiponectin-related genes (ADIPOQ, ADIPOR1, ADIPOR2) have been examined in relation to circulating adiponectin levels and obesity phenotypes, but despite differences in adiponectin levels and obesity prevalence by race, few studies have included black participants. Using cross-sectional interview data and blood samples collected from 990 black and 977 white women enrolled in the Southern Community Cohort Study (SCCS) from 2002 to 2006, we examined 25 SNPs in ADIPOQ, 19 in ADIPOR1, and 27 in ADIPOR2 in relation to serum adiponectin levels and BMI using race-stratified linear regression models adjusted for age and percentage African ancestry. SNP rs17366568 in ADIPOQ was significantly associated with serum adiponectin levels in white women only (adjusted mean adiponectin levels = 15.9 for G/G genotype, 13.7 for A/G, and 9.3 for A/A, P = 0.00036). No other SNPs were associated with adiponectin or BMI among blacks or whites. Because adiponectin levels as well as obesity are highly heritable and vary by race but associations with polymorphisms in the ADIPOQ, ADIPOR1, and ADIPOR2 genes have been few in this and other studies, future work including large populations from diverse racial groups is needed to detect additional genetic variants that influence adiponectin and BMI.

Identification of possible genetic polymorphisms involved in cancer cachexia: a systematic review

Cancer cachexia is a polygenic and complex syndrome. Genetic variations in regulation of the inflammatory response, muscle and fat metabolic pathways, and pathways in appetite regulation are likely to contribute to the susceptibility or resistance to developing cancer cachexia. A systematic search of Medline and EmBase databases, covering 1986-2008 was performed for potential candidate genes/genetic polymorphisms relating to cancer cachexia. Related genes were then identified using pathway functional analysis software. All candidate genes were reviewed for functional polymorphisms or clinically significant polymorphisms associated with cachexia using the OMIM and GeneRIF databases. Genes with variants which had functional or clinical associations with cachexia and replicated in at least one study were entered into pathway analysis software to reveal possible network associations between genes. A total of 184 polymorphisms with functional or clinical relevance to cancer cachexia were identified in 92 candidate genes. Of these, 42 polymorphisms (in 33 genes) were replicated in more than one study with 13 polymorphisms found to influence two or more hallmarks of cachexia (i.e. inflammation, loss of fat mass and/or lean mass and reduced survival). Thirty-three genes were found to be significantly interconnected in two major networks with four genes (ADIPOQ, IL6, NFKB1 and TLR4) interlinking both networks. Selection of candidate genes and polymorphisms is a key element of multigene study design. The present study provides an initial framework to select genes/polymorphisms for further study in cancer cachexia, and to develop their potential as susceptibility biomarkers of developing cachexia.

Molecular mechanisms of signal transduction via adiponectin and adiponectin receptors

The adipocytokine adiponectin and its receptor (AdipoR) comprise a new receptor-ligand system that is involved in a variety of clinically important morbidities such as obesity, type 2 diabetes and cardiovascular diseases. Adiponectin exerts a multitude of beneficial and tissue specific effects depending on its unique, tightly regulated multimerization behavior. Post-translational modifications are essential for the multimer assembly before secretion and protein stability in the circulation. AdipoR1 and 2 have been discovered as a new class of heptahelix receptors structurally and functionally distinct from G-protein-coupled receptors. Both AdipoRs bind adiponectin and the downstream signaling of both AdipoRs is mediated mainly by phosphorylation of AMPK and activation of peroxisome proliferator-activated receptor α, which influence the lipid and glucose metabolism of skeletal muscle and liver cells as well as inflammatory processes and vascular endothelial integrity. Several intracellular binding partners of the AdipoR N-terminus such as APPL1, CK2ß; and ERp46 have been identified and shown to control receptor signaling. Adiponectin has also been reported to modulate the dimerization and internalization of AdipoRs, which provides new insights into the molecular characteristics of this unusual receptor. The understanding of the functional mechanisms of adiponectin signal transduction is critical to benefit from the full therapeutic potential of the adiponectin-AdipoR system.

Studies of gene variants related to inflammation, oxidative stress, dyslipidemia, and obesity: implications for a nutrigenetic approach

Obesity is currently considered a serious public health issue due to its strong impact on health, economy, and quality of life. It is considered a chronic low-grade inflammation state and is directly involved in the genesis of metabolic disturbances, such as insulin resistance and dyslipidemia, which are well-known risk factors for cardiovascular disease. Furthermore, there is evidence that genetic variation that predisposes to inflammation and metabolic disturbances could interact with environmental factors, such as diet, modulating individual susceptibility to developing these conditions. This paper aims to review the possible interactions between diet and single-nucleotide polymorphisms (SNPs) in genes implicated on the inflammatory response, lipoprotein metabolism, and oxidative status. Therefore, the impact of genetic variants of the peroxisome proliferator-activated receptor-(PPAR-)gamma, tumor necrosis factor-(TNF-)alpha, interleukin (IL)-1, IL-6, apolipoprotein (Apo) A1, Apo A2, Apo A5, Apo E, glutathione peroxidases 1, 2, and 4, and selenoprotein P exposed to variations on diet composition is described.

Adiponectin gene SNP276 variants and central obesity confer risks for hyperglycemia in indigenous Taiwanese

This cross-sectional study analyzed the effects of two single nucleotide polymorphisms (SNP) of the adiponectin gene, SNP45 and SNP276, on hyperglycemia in indigenous Taiwanese, and whether central obesity modulates the effects of these SNPs. Overall, 550 indigenous Taiwanese were recruited for this cross-sectional study. The subjects were categorized into a hyperglycemic group if fasting plasma glucose was > 126 mg/dL (n = 88) or the control group if fasting plasma glucose was < 100 mg/dL (n = 462). The SNP276 TT homozygote carried greater hyperglycemia risk than SNP276 GG [odds ratio (OR) = 2.67, 95% confidence interval (CI) = 1.05-6.78], but not heterozygote (OR = 1.54, 95% CI = 0.95-2.50). SNP45 T > G was not associated with hyperglycemia risk. In multivariate-adjusted modeling, we found a significant relationship between SNP276 T carriers (GT + TT) (OR = 2.06, 95% CI = 1.10-3.88) and central obesity (OR = 4.50, 95% CI = 1.91-10.61) with hyperglycemia. Compared with non-central-obese carriers of SNP276 GG, non-central-obese SNP276 T carriers, and central obese subjects with SNP276 GG and SNP276 T carriers had 5.50, 8.31 and 13.76-fold, respectively, higher risks for hyperglycemia; obese carriers of the T-containing variants experienced a combined risk for hyperglycemia. Furthermore, the hyperglycemic risks were more pronounced in leaner (non-central-obese) individuals carrying the T variant than the central-obese individuals. The adiponectin SNP276 T variant and central obesity had independent and additive effects on hyperglycemia risks. These findings may provide valuable information regarding preventive strategies that might be useful to prevent or treat diabetes and its related complications.

Low serum adiponectin levels are associated with systemic organ failure in acute pancreatitis

OBJECTIVES

Obesity markedly increases the risk of severe acute pancreatitis (SAP), possibly through the action of adipokines. We tested the hypothesis that serum adiponectin, the primary anti-inflammatory adipokine, is associated with functional polymorphisms in the adiponectin gene (ADIPOQ) and inversely associated with SAP.

METHODS

Severe AP was defined as the presence of remote organ failure. ADIPOQ polymorphisms rs2241766T>G and rs1501299G>T were evaluated by DNA sequencing. Serum samples were assayed using a Luminex assay (Luminex, Austin, Tex).

RESULTS

One hundred thirty-three patients with AP and 94 healthy controls were ascertained. Adiponectin levels were measured in 60 patients with early serum samples (27 patients with mild AP and 33 patients with SAP). Adiponectin levels from days 1 to 3 were inversely correlated with body mass index (BMI) (rho = -0.49; P = 0.002) and were significantly lower for patients with SAP (median, 3.74 microg/mL) than those with mild AP (6.58 microg/mL; P = 0.02). Neither ADIPOQ polymorphism affected susceptibility to or severity of AP. A receiver operating characteristics curve using adiponectin levels as the severity predictor provided an area under the curve of 0.75.

CONCLUSIONS

Serum adiponectin levels in patients with AP are inversely correlated with BMI and organ dysfunction. Further studies are needed to determine whether adiponectin is a marker of low BMI or if it provides significant protection from SAP.

Interaction of ADIPOQ genetic polymorphism with blood pressure and plasma cholesterol level on the risk of coronary artery disease

BACKGROUND

The protective effect of +45T >G polymorphism in the adiponectin gene (ADIPOQ) on coronary artery disease (CAD) has been demonstrated in European populations, so this study investigated the effect of +45T >G polymorphism on the risk of CAD and its interactions with other metabolic risk factors in a Chinese population.

METHODS AND RESULTS

The +45T >G polymorphism (rs2241766) of ADIPOQ was genotyped in 600 patients with angiographically diagnosed CAD and in 718 controls. The G allele at the +45T >G polymorphism was associated with a lower risk of CAD (odds ratio (OR), 0.76; 95% confidence interval (CI), 0.64-0.89; P=0.001). The protective effect of the G allele at +45T >G polymorphism was magnified at blood pressure <140/90 mmHg (OR, 0.65; 95%CI, 0.51-0.82; P=0.0004), but disappeared at blood pressure >or=140/90 mmHg (OR, 0.98; 95%CI, 0.76-1.28; P=0.93), indicating an interaction between +45T >G polymorphism and blood pressure on CAD risk (P=0.02 for interaction). A similar interaction was also observed between plasma cholesterol level and the +45T >G polymorphism.

CONCLUSIONS

An association of ADIPOQ genetic polymorphism with CAD risk is modified by traditional risk factors, such as blood pressure and plasma cholesterol level.

Adiponectin in health and disease: evaluation of adiponectin-targeted drug development strategies

Adiponectin is a secretory protein predominantly expressed by adipocytes and released at a high rate into circulation. The ease with which the levels of adiponectin can be measured owing to its high abundance, small diurnal variation and high stability in plasma have made it a popular target for measurements in many clinical studies. It has emerged as a valuable biomarker for insulin sensitivity, cardiovascular risk and inflammation. However, adiponectin levels have been measured in many additional disease states. Preclinical studies not only have implicated adiponectin as an outstanding biomarker but also have demonstrated direct cardio-protective and insulin-sensitizing properties to be associated with the protein. Adiponectin might, therefore, be a viable protein therapeutic that could be supplied in a recombinant form in the context of type 2 diabetes and cardiovascular disease. However, the high abundance, complex tertiary and quaternary structure and rapid turnover might make chronic administration of the protein rather challenging.

A novel association of a polymorphism in the first intron of adiponectin gene with type 2 diabetes, obesity and hypoadiponectinemia in Asian Indians

Adiponectin is an adipose tissue specific protein that is decreased in subjects with obesity and type 2 diabetes. The objective of the present study was to examine whether variants in the regulatory regions of the adiponectin gene contribute to type 2 diabetes in Asian Indians. The study comprised of 2,000 normal glucose tolerant (NGT) and 2,000 type 2 diabetic, unrelated subjects randomly selected from the Chennai Urban Rural Epidemiology Study (CURES), in southern India. Fasting serum adiponectin levels were measured by radioimmunoassay. We identified two proximal promoter SNPs (-11377C-->G and -11282T-->C), one intronic SNP (+10211T-->G) and one exonic SNP (+45T-->G) by SSCP and direct sequencing in a pilot study (n = 500). The +10211T-->G SNP alone was genotyped using PCR-RFLP in 4,000 study subjects. Logistic regression analysis revealed that subjects with TG genotype of +10211T-->G had significantly higher risk for diabetes compared to TT genotype [Odds ratio 1.28; 95% Confidence Interval (CI) 1.07-1.54; P = 0.008]. However, no association with diabetes was observed with GG genotype (P = 0.22). Stratification of the study subjects based on BMI showed that the odds ratio for obesity for the TG genotype was 1.53 (95%CI 1.3-1.8; P < 10(-7)) and that for GG genotype, 2.10 (95% CI 1.3-3.3; P = 0.002). Among NGT subjects, the mean serum adiponectin levels were significantly lower among the GG (P = 0.007) and TG (P = 0.001) genotypes compared to TT genotype. Among Asian Indians there is an association of +10211T-->G polymorphism in the first intron of the adiponectin gene with type 2 diabetes, obesity and hypoadiponectinemia.

Promoter adiponectin polymorphisms and waist/hip ratio variation in a prospective French adults study

BACKGROUND

Adiponectin expression and plasma concentrations are decreased in human and animal models of obesity. Several single nucleotide polymorphisms (SNPs) in the adiponectin gene are known to influence the plasmatic concentration of the encoded protein. Some of these adiponectin polymorphisms have been associated with BMI in cross-sectional studies.

OBJECTIVE

The aim of our study was to examine the longitudinal relationships between adiponectin gene polymorphisms and anthropometric indices.

DESIGN

Two adiponectin gene (ADIPOQ) SNPs, -11391G>A and -11377C>G, were genotyped in 837 French Caucasian subjects from the SUpplémentation en VItamines et Minéraux Anti-oXydants (SU.VI.MAX) cohort. Anthropometric scores were measured at three clinical examinations over a 7-year period.

RESULTS

For -11391G>A as well as for -11377C>G, we detected no association between the variant allele and anthropometric measurements at baseline. Considering longitudinal effects, we detected moderately higher waist-to-hip ratio (WHR) changes for the carriers of the -11391A (P=0.02) and -11377C (P=0.03) allele over the follow-up of the study. -11391G>A and -11377C>G define haplotypes associated also with WHR measurements and their changes over the follow-up of the study. Diploid configurations that combine -11391A and -11377C were associated with significantly higher WHR changes (DeltaCE: P=0.02) compared to other haplotypes. In addition, higher adiponectin levels were observed in AC/AC diplotypes compared to GG/GG carriers (P<0.0001).

CONCLUSION

In the SU.VI.MAX study, genetic variations in the adiponectin gene affect abdominal fat gain over life span.

ACDC/adiponectin and PPAR-gamma gene polymorphisms: implications for features of obesity

OBJECTIVE

The main purpose of this study was to investigate associations of single-nucleotide polymorphisms (SNPs) in the adipocyte C1q and collagen domain-containing (ACDC) gene and its regulator, the nuclear peroxisome proliferator-activated receptor (PPAR)-gamma gene, with body fat mass and its topographical distribution in postmenopausal women.

RESEARCH METHODS AND PROCEDURES

Participants were 1501 healthy women, 60 to 85 years old, who were genotyped for four SNPs in the ACDC gene (-11391G/A, -11377C/G, +45T/G, +276G/T) and the Pro12Ala SNP in the PPAR-gamma gene. Total body fat mass and the central to peripheral fat mass ratio (CFM/PFM ratio) were measured using DXA. Adiponectin and homeostasis model assessment of insulin resistance were measured in 287 subjects.

RESULTS

The -11377C/G SNP was associated with adiponectin (p < 0.001) and the CFM/PFM ratio (p = 0.005); the G allele being associated with low adiponectin and high CFM/PFM ratio. Similar associations of adiponectin (p = 0.0001) and the CFM/PFM ratio (p = 0.002) characterized the 1_2 (G_G) promoter haplotype (11391G/A_-11377C/G). Genotype variation of SNP Pro12Ala was associated with total body fat mass (p = 0.04); women with GG being the most obese (p = 0.01). The Ala/Ala (GG) genotype of Pro12Ala SNP interacted with the CC genotype of SNP-11377C/G in the determination of BMI (p = 0.001), when analyzed using a codominant model.

DISCUSSION

Polymorphisms in the ACDC gene are associated with body fat distribution, whereas the Pro12Ala polymorphism in PPAR-gamma is associated with overall adiposity, apparently in interaction with an ACDC promoter SNP.

Association between plasma IL-6, the IL6 -174G>C gene variant and the metabolic syndrome in type 2 diabetes mellitus

Elevated plasma interleukin-6 (IL-6) is associated with coronary heart disease (CHD), impaired glucose tolerance (IGT), and type 2 diabetes (T2DM). We and others have described an association between the human interleukin-6 -174G>C gene variant and body mass index (BMI). Within our previous sample of subjects with T2DM, we measured plasma IL-6 and grouped subjects by the WHO-defined metabolic syndrome, in order to study the association between the -174G>C gene variant, plasma IL-6 and the metabolic syndrome (and component parts). Genotype was obtained in 571 Caucasian subjects with plasma IL-6 measures. There was a significant association between genotype and plasma IL-6 (GG vs GC vs CC: 3.23+/-0.93 pg/ml vs 3.42+/-0.95 pg/ml vs 4.16+/-1.18 pg/ml, p=0.02; for GG/GC vs CC p=0.008). No interactions were observed between genotype and the individual components of the metabolic syndrome in determining plasma IL-6. Increased plasma IL-6 was also associated with the number of components (none vs 1 vs 2 vs > or =3: 2.67+/-0.71 pg/ml vs 2.97+/-0.94 pg/ml vs 4.07+/-1.13 pg/ml, p<0.0001). Within the sample, 76% of CC compared to 56% of GG subjects had the metabolic syndrome (p=0.007). Further analysis of association between the genotype and the components of the metabolic syndrome revealed no further associations than that with BMI previously described. The association of this gene variant with the metabolic syndrome is intimately linked with obesity per se. Further prospective work is required to explore the effect of this gene variant in relation to obesity, the metabolic syndrome and 'prediabetes'.

Metabolic syndrome pathophysiology: the role of adipose tissue

Several pathophysiological explanations for the metabolic syndrome have been proposed involving insulin resistance, chronic inflammation and ectopic fat accumulation following adipose tissue saturation. However, current concepts create several paradoxes, including limited cardiovascular risk reduction with intensive glucose control in diabetics, therapies that result in weight gain (PPAR agonists), and presence of some of the metabolic traits among some lipodystrophies. We propose the functional failure of an organ, in this case, the adipose tissue as a model to interpret its manifestations and to reconcile some of the apparent paradox. A cornerstone of this model is the failure of the adipose tissue to buffer postprandial lipids. In addition, homeostatic feedback loops guide physiological and pathological adipose tissue activities. Fat turnover is determined by a complex equilibrium in which insulin is a main factor but not the only one. Chronically inadequate energy balance may be a key factor, stressing the system. In this situation, an adipose tissue functional failure occurs resulting in changes in systemic energy delivery, impaired glucose consumption and activation of self-regulatory mechanisms that extend their influence to whole body homeostasis system. These include changes in adipokines secretion and vascular effects. The functional capacity of the adipose tissue varies among subjects explaining the incomplete overlapping among the metabolic syndrome and obesity. Variations at multiple gene loci will be partially responsible for these interindividual differences. Two of those candidate genes, the adiponectin (APM1) and the perilipin (PLIN) genes, are discussed in more detail.

Adiponectin and adiponectin receptor gene variants in relation to resting metabolic rate, respiratory quotient, and adiposity-related phenotypes in the Quebec Family Study

BACKGROUND

Despite adiponectin's presumed role in fatty acid oxidation and energy homeostasis, little is known about the effect of gene variants on substrate oxidation, energy expenditure, and adiposity-related phenotypes.

OBJECTIVE

We examined the effects of genetic variation in adiponectin (ADIPOQ) and adiponectin receptors 1 and 2 (ADIPOR1 and ADIPOR2) on resting metabolic rate, respiratory quotient (RQ), and adiposity-related phenotypes.

DESIGN

We studied the associations of ADIPOQ, ADIPOR1, and ADIPOR2 polymorphisms with resting metabolic rate, RQ, and body mass index, percentage body fat, sum of 6 skinfold thicknesses, waist circumference, and total, subcutaneous, and visceral fat in 759 participants in the Québec Family Study.

RESULTS

The ADIPOQ 45T-->G single-nucleotide polymorphism (SNP) was significantly (P = 0.0002 to 0.04) associated with overall adiposity and abdominal adiposity; the rare homozygotes (G/G) had a leaner phenotype than did the carriers of the common allele. One SNP each in the putative promoter of ADIPOR1 (ie, -3882T-->C) and ADIPOR2 (ie, IVS1 -1352G-->A) was associated with RQ (P = 0.03 and 0.04, respectively), and the association was even stronger in nonobese persons (P = 0.02 and 0.003). Carriers of the common alleles (ADIPOR1 T and ADIPOR2 G alleles) had a lower RQ than did the rare homozygotes. A significant genotype-by-genotype interaction (P = 0.0002 to 0.02) was found between SNPs in the promoters of ADIPOQ (-3971A-->G) and ADIPOR1 (-3882T-->C). Subjects carrying the minor ADIPOQ allele (G allele) who were rare homozygotes (C/C) for the ADIPOR1 SNP had a higher RQ (P = 0.003) and greater overall (P < 0.03) and abdominal (P < 0.05) adiposity than did persons with other genotype combinations.

CONCLUSIONS

Previous findings that the ADIPOQ 45T-->G variant contributes to overall fatness and abdominal obesity are confirmed. Moreover, variants in the promoter region of both ADIPOR genes contribute to substrate oxidation.

The adiponectin gene is associated with adiponectin levels but not with characteristics of the insulin resistance syndrome in healthy Caucasians

Low concentrations of adiponectin, the protein product of the APM1 gene, have been reported to be associated with obesity and insulin resistance. However, contrasting results have been described on the genetic variability in APM1 and characteristics of the metabolic syndrome and adiponectin serum concentrations. In the present study, we investigated the association of the two most well-known SNPs of APM1 (+45T>G and +276G>T) and their haplotypes, with serum adiponectin concentrations, metabolic parameters and intima-media thickness of the carotid arteries in 1,745 well-phenotyped asymptomatic unrelated Caucasian subjects of the SAPHIR cohort. The common T-allele (88.5%) of SNP +45T>G and the common G-allele (70.5%) of SNP +276G>T were associated with significantly lower serum adiponectin levels (P = 0.0008 and P = 0.00005, respectively). The most frequent haplotype TG (59.0%) defined by both loci showed a strong association with lower serum adiponectin concentrations (P = 0.000000002). A clear effect per copy of the respective haplotype was observed. This association was most pronounced in lean and insulin-sensitive subjects. The two less common haplotypes TT (29.5%) and GG (11.5%) were associated with higher serum adiponectin levels in a dose-dependent association. Interestingly, no significant association between the adiponectin 45-276 haplotypes and the majority of parameters of the metabolic syndrome or intima-media thickness of the carotid arteries was found in our study. In summary, we replicated a strong association of the adiponectin 45-276 genotypes and haplotypes with adiponectin levels in healthy Caucasians. However, we could not confirm an association of this gene locus with metabolic parameters of the insulin resistance syndrome.

Plasma adiponectin, T94G gene polymorphism and PAI-1 in patients with and without hypertension

BACKGROUND

Reduced adiponectin level has been associated with metabolic syndrome, type 2 diabetes, coronary artery disease and gene polymorphisms, but the interrelationships of T94G genotype, plasma adiponectin and plasminogen activator inhibitor-1 (PAI-1) are less understood.

PATIENTS AND METHODS

The T94G genotypes and plasma levels of adiponectin, and PAI-1 were determined in 568 Chinese patients, 212 with and 356 without hypertension, to study the possible associations of T94G genotype, plasma adiponectin, PAI-1 and blood pressure.

RESULTS

Hypertensive patients showed significantly lower plasma adiponectin (9.7 +/- 11.1 vs. 11.5 +/- 10.0 microg/ml, p = 0.04) and higher PAI-1 (p < 0.001) levels but not significantly greater adiponectin TT genotype percentage (38.7 vs. 33.5%) and T allele frequency (0.620 vs. 0.585) than normotensive subjects. Plasma adiponectin was inversely related to PAI-1 activity (r = -0.09, p = 0.03) and antigen (r = -0.202, p < 0.001). Furthermore, the TT genotypic group showed significantly lower plasma adiponectin level (10.4 +/- 10.5 vs. 13.4 +/- 10.8 mug/ml, p = 0.03) and higher plasma PAI-1 activity (17.0 +/- 9.7 vs. 13.5 +/- 7.6 IU/ml, p = 0.003) and antigen (32.3 +/- 22.7 vs. 25.9 +/- 14.7 ng/ml, p = 0.01) than the GG genotypic group. Multiple linear regression analysis in all study subjects, in men and in normotensives documented an impact of adiponectin T94G genotype on plasma levels of adiponectin (p = 0.007, 0.003 and 0.03) and PAI-1 activity (p = 0.02, 0.03 and 0.04) and antigen (p = 0.03, 0.007 and 0.04) after adjustment for potential confounding factors.

CONCLUSIONS

The present study demonstrated a significant correlation of the TT genotype with lower plasma adiponectin and higher plasma PAI-1 levels in a Chinese population. The contribution of this genotype seemed greater in men and normotensives. It suggested the adiponectin gene T94G polymorphism might affect the regulation of circulating adiponectin and PAI-1.

Adiponectin and its gene variants as risk factors for insulin resistance, the metabolic syndrome and cardiovascular disease

The increasing prevalence of obesity and metabolic syndrome/insulin resistance has attracted considerable interest due to their identification as risk factors for cardiovascular disease and, hence, targets for cardiovascular disease prevention. This review focuses on adiponectin, the most profusely secreted protein from adipose tissue, which itself is being increasingly recognised as an important and very active endocrine organ, secreting a wide range of biologically active substances known as adipokines or adipocytokines. Adiponectin has been demonstrated to have insulin sensitising effects, and secretion of adiponectin is reduced as adipose tissue mass increases. Adiponectin has also been demonstrated to have anti-inflammatory and anti-atherogenic properties, and is independently associated with cardiovascular disease. The evidence that suggests adiponectin plays a role in the relationship between obesity and insulin resistance, and also insulin resistance and cardiovascular disease, is examined. Variation in the adiponectin gene is one tool to determine whether this relationship is causal. The association of identified variants with human disease, specifically obesity and its consequences, type 2 diabetes and cardiovascular disease is reviewed. This data may enable patients at greater risk of the adverse effects of obesity to be identified and, as such, benefit from more targeted therapy of its consequences.

The human obesity gene map: the 2005 update

This paper presents the 12th update of the human obesity gene map, which incorporates published results up to the end of October 2005. Evidence from single-gene mutation obesity cases, Mendelian disorders exhibiting obesity as a clinical feature, transgenic and knockout murine models relevant to obesity, quantitative trait loci (QTL) from animal cross-breeding experiments, association studies with candidate genes, and linkages from genome scans is reviewed. As of October 2005, 176 human obesity cases due to single-gene mutations in 11 different genes have been reported, 50 loci related to Mendelian syndromes relevant to human obesity have been mapped to a genomic region, and causal genes or strong candidates have been identified for most of these syndromes. There are 244 genes that, when mutated or expressed as transgenes in the mouse, result in phenotypes that affect body weight and adiposity. The number of QTLs reported from animal models currently reaches 408. The number of human obesity QTLs derived from genome scans continues to grow, and we now have 253 QTLs for obesity-related phenotypes from 61 genome-wide scans. A total of 52 genomic regions harbor QTLs supported by two or more studies. The number of studies reporting associations between DNA sequence variation in specific genes and obesity phenotypes has also increased considerably, with 426 findings of positive associations with 127 candidate genes. A promising observation is that 22 genes are each supported by at least five positive studies. The obesity gene map shows putative loci on all chromosomes except Y. The electronic version of the map with links to useful publications and relevant sites can be found at http://obesitygene.pbrc.edu.

Genetic predispositions to low-grade inflammation and type 2 diabetes

Insulin resistance and cardiovascular disease share common pathophysiological mechanisms, as the chronic activation of the innate immune system. This system constitutes the first line of body's defense and is constituted by different barriers (e.g., epithelia, adipose tissue) and different blood and tissue components (e.g., macrophages, neutrophils). This system generates the acute-phase response in which different acute-phase proteins and cytokines are produced in response to different aggressions as infections and traumatisms. The aim of this response is to eradicate these agents, to repair the harmed tissues, and, through increased insulin resistance, to optimize the energetic substrates, which will be drained to vital tissues and organs (i.e., brain and the immune system). Evolutionary pressures have led to survival of the fittest individuals, those with the genetics that allows the best defense against infection and periods of famine. Evidence is reported according to which gene polymorphisms in the molecules regulating the inflammatory cascade are associated with body composition, insulin action, and characteristics of the metabolic syndrome. The evolutive advantages of increased inflammatory responses, hypersecretion of proinflammatory cytokines [tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1beta, IL-6, and IL-18], or decreased anti-inflammatory molecules (adiponectin, certain TNF-alpha isoforms, soluble CD14, etc.), would lead in westernized countries to chronic inflammation conditions, such as obesity and type 2 diabetes, resulting in cardiovascular disease.

Genetic architecture of the APM1 gene and its influence on adiponectin plasma levels and parameters of the metabolic syndrome in 1,727 healthy Caucasians

The associations of the adiponectin (APM1) gene with parameters of the metabolic syndrome are inconsistent. We performed a systematic investigation based on fine-mapped single nucleotide polymorphisms (SNPs) highlighting the genetic architecture and their role in modulating adiponectin plasma concentrations in a particularly healthy population of 1,727 Caucasians avoiding secondary effects from disease processes. Genotyping 53 SNPs (average spacing of 0.7 kb) in the APM1 gene region in 81 Caucasians revealed a two-block linkage disequilibrium (LD) structure and enabled comprehensive tag SNP selection. We found particularly strong associations with adiponectin concentrations for 11 of the 15 tag SNPs in the 1,727 subjects (five P values <0.0001). Haplotype analysis provided a thorough differentiation of adiponectin concentrations with 9 of 17 haplotypes showing significant associations (three P values <0.0001). No significant association was found for any SNP with the parameters of the metabolic syndrome. We observed a two-block LD structure of APM1 pointing toward at least two independent association signals, one including the promoter SNPs and a second spanning the relevant exons. Our data on a large number of healthy subjects suggest a clear modulation of adiponectin concentrations by variants of APM1, which are not merely a concomitant effect in the course of type 2 diabetes or coronary artery disease.

Interactions between noncontiguous haplotypes in the adiponectin gene ACDC are associated with plasma adiponectin

Adiponectin, an adipocyte protein important in insulin sensitization and cardioprotection, has a strong genetic component. We hypothesized that variants in the adiponectin gene (adipocyte collagen-domain containing [ACDC]) contribute to adiponectin levels in a biracial adolescent cohort. We genotyped 11 ACDC single nucleotide polymorphisms (SNPs) in 631 non-Hispanic white and 553 African-American unrelated adolescents in grades 5-12 randomly selected from the Princeton School District Study. ACDC SNPs -11,391 (A allele), -10,068 (G allele), and +276 (T allele) were associated with higher adiponectin, adjusting for sex, puberty stage, BMI Z score, and waist Z score. Contiguous two-SNP haplotypes of promoter variants -11,391/-10,068 were significantly associated with adiponectin levels in whites and African Americans (P < 0.0001 and 0.03, respectively). Extended haplotypes from the promoter through the second intron (-11,391 to +349) strongly associated with adiponectin in whites (P = 6 x 10(-11)) and African Americans (P = 0.004), but haplotypes of first intron SNPs -4,521 to -657 did not (P > 0.2). Noncontiguous haplotypes or interactions between two-SNP (-11,391/-10,068) and three-SNP (+45, +276, and +349) haplotypes predicted adiponectin better than either region alone. Variants of ACDC are associated with adiponectin levels in whites and African Americans. Interactions between noncontiguous ACDC haplotypes strongly influence adiponectin levels, suggesting nonadditive and potentially cis relationships between these regions.