Serum uric acid concentrations and SLC2A9 genetic variation in Hispanic children: the Viva La Familia Study

Single Nucleotide Variants of the SLC2A9 Gene are Associated With Hyperuricemia in Mexican Patients With Type 2 Diabetes

BACKGROUND

Chronic kidney disease (CKD) due to diabetes is the third leading cause of death in Mexico. A relationship between high serum uric acid (SUA) levels and kidney disease have been demonstrated. On the other hand, variants of the SLC2A9 gene have been associated with elevated SUA concentrations. This study evaluated the associations of the rs11722228, rs3775948, rs7678287, and rs1014290 variants with hyperuricemia and biochemical parameters in patients with type 2 diabetes (T2D).

METHODS

The study included 1036 Mexican subjects with T2D. Patients were grouped based on the presence (n = 462) or absence (n = 574) of diabetic kidney disease (DKD). SUA concentrations and biochemical parameters were determined. Samples were genotyped through real-time polymerase chain reaction. Associations between genetic variants and hyperuricemia were analyzed by univariate and multivariate models adjusting for covariates.

RESULTS

SUA levels and hyperuricemia prevalence were higher in the DKD group. rs3775948 and rs1014290 showed negative associations with hyperuricemia in the whole sample and in patients without DKD. rs7678287 was positively correlated with SUA and hyperuricemia in patients without DKD, whereas rs11722228 was a risk factor only in the DKD group. The presence of DKD and elevated triglycerides and total cholesterol were significant factors associated with hyperuricemia.

CONCLUSIONS

Variants rs3775948 and rs1014290 exhibit protective effects, while rs7678287 and rs11722228 may confer increased risk of hyperuricemia in Mexican patients with T2D. Analysis of SLC2A9 gene variants could help in detecting patients at increased risk of kidney or cardiovascular complications due to hyperuricemia.

Mendelian Randomization Studies: Opening a New Window in the Study of Metabolic Diseases and Chronic Kidney Disease

It is widely recognized that a strong correlation exists between metabolic diseases and chronic kidney disease (CKD). Based on bibliometric statistics, the overall number of Mendelian randomization (MR) analysis in relation to metabolic diseases and CKD has increased since 2005. In recent years, this topic has emerged as a significant area of research interest. In clinical studies, RCTs are often limited due to the intricate causal interplay between metabolic diseases and CKD, which makes it difficult to ascertain the precise etiology of these conditions definitively. In MR studies, genetic variation is incorporated as an instrumental variable (IV). They elucidate the possible causal relationships between associated risk factors and disease risks by including individual innate genetic markers. It is widely believed that MR avoids confounding and can reverse effects to the greatest extent possible. As an increasingly popular technology in the medical field, MR studies have become a popular technology in causal relationships investigation, particularly in epidemiological etiology studies. At present, MR has been widely used for the investigation of medical etiologies, drug development, and decision-making in public health. The article aims to offer insights into the causal relationship between metabolic diseases and CKD, as well as strategies for prevention and treatment, through a summary of MR-related research on these conditions.

The role of high fat diet on serum uric acid level among healthy male first degree relatives of type 2 diabetes mellitus

First-degree relatives (FDR) of type 2 diabetes mellitus have increased risk of developing insulin resistance-related disorders including hyperuricemia. We investigated metabolic profile and serum uric acid (SUA) metabolism in response to high-fat diet among healthy male FDR in comparison to those without family history of diabetes. A total of 30 FDR and 30 non-FDR subjects completed a 5-days-hypercaloric diet with fat added to regular daily intake. Despite similar insulin response, FDR displayed different changes in SUA compared to non-FDR subjects (0.26 ± 0.83 mg/dL vs - 0.21 ± 0.78 mg/dL, p = 0.028). In subgroup analyses stratified by body mass index and waist circumference, significant different SUA changes between FDR and non-FDR subjects were only found in obese (0.48 ± 0.87 mg/dL vs - 0.70 ± 0.71 mg/dL, p = 0.001) and centrally obese (0.59 ± 0.83 mg/dL vs - 0.55 ± 0.82 mg/dL, p = 0.011) subgroups. In multivariate analysis, visceral adiposity seemed mediating the different response in SUA metabolism between FDR and non-FDR subjects induced by short-term obesogenic diet.

Novel Insights into the Effects of Genetic Variants on Serum Urate Response to an Acute Fructose Challenge: A Pilot Study

Studies have shown that genetic variations can influence metabolic response to nutrient intake, and that diets rich in fructose contribute to hyperuricemia. In this pilot study, our aim was to determine the variability of serum urate in response to an acute fructose challenge and to investigate if genetic variants would affect this response in young to middle-aged adults who self-reported as Black or White. Fifty-seven participants consumed a fructose-rich beverage after an overnight fast. Blood was drawn at five time points (baseline, 30, 60, 120, and 180 min after consumption). Thirty urate-related single nucleotide polymorphisms (SNPs) were analyzed for their associations with baseline serum urate and its percent changes, using a two-step modeling approach followed by meta-analysis. At baseline, serum urate (mg/dL, mean ± SD) was higher in Whites (5.60 ± 1.01 vs. 5.37 ± 0.96), men (6.17 ± 1.14 vs. 5.24 ± 0.79), and those with obesity (5.69 ± 1.08 vs. 5.42 ± 1.06 vs. 5.34 ± 0.80). Three SNPs were significantly associated with baseline serum urate or its percent changes, and six SNPs were nominally associated with percent changes in serum urate. In summary, our results showed that genetic variants could play a role in short-term urate metabolism.

Polygenic Risk Score Improves Cataract Prediction in East Asian Population

Cataracts, characterized by crystalline lens opacities in human eyes, is the leading cause of blindness globally. Due to its multifactorial complexity, the molecular mechanisms remain poorly understood. Larger cohorts of genome-wide association studies (GWAS) are needed to investigate cataracts’ genetic basis. In this study, a GWAS was performed on the largest Han population to date, analyzing a total of 7079 patients and 13,256 controls from the Taiwan Biobank (TWB) 2.0 cohort. Two cataract-associated SNPs with an adjustment of p < 1 × 10−7 in the older groups and nine SNPs with an adjustment of p < 1 × 10−6 in the younger group were identified. Except for the reported AGMO in animal models, most variations, including rs74774546 in GJA1 and rs237885 in OXTR, were not identified before this study. Furthermore, a polygenic risk score (PRS) was created for the young and old populations to identify high-risk cataract individuals, with areas under the receiver operating curve (AUROCs) of 0.829 and 0.785, respectively, after covariate adjustments. Younger individuals had 17.45 times the risk while older people had 10.97 times the risk when comparing individuals in the highest and lowest PRS quantiles. Validation analysis on an independent TWB1.0 cohort revealed AUROCs of 0.744 and 0.659.

Weak Association Between Genetic Markers of Hyperuricemia and Cardiorenal Outcomes: Insights From the STANISLAS Study Cohort With a 20-Year Follow-Up

Background Hyperuricemia is associated with poor cardiovascular outcomes, although it is uncertain whether this relationship is causal in nature. This study aimed to: (1) assess the heritability of serum uric acid (SUA) levels, (2) conduct a genome-wide association study on SUA levels, and (3) investigate the association between certain single-nucleotide polymorphisms and target organ damage. Methods and Results The STANISLAS (Suivi Temporaire Annuel Non-Invasif de la Santé des Lorrains Assurés Sociaux) study cohort is a single-center longitudinal cohort recruited between 1993 and 1995 (visit 1), with a last visit (visit 4 [V4]) performed ≈20 years apart. Serum lipid profile, SUA, urinary albumin/creatinine ratio, estimated glomerular filtration rate, 24-hour ambulatory blood pressure monitoring, transthoracic echocardiography, pulse wave velocity, and genotyping for each participant were assessed at V4. A total of 1573 participants were included at V4, among whom 1417 had available SUA data at visit 1. Genome-wide association study results highlighted multiple single-nucleotide polymorphisms on the SLC2A9 gene linked to SUA levels. Carriers of the most associated mutated SLC2A9 allele (rs16890979) had significantly lower SUA levels. Although SUA level at V4 was highly associated with diabetes, prediabetes, higher body mass index, CRP (C-reactive protein) levels, estimated glomerular filtration rate variation (visit 1-V4), carotid intima-media thickness, and pulse wave velocity, rs16890979 was only associated with higher carotid intima-media thickness. Conclusions Our findings demonstrate that rs16890979, a genetic determinant of SUA levels located on the SLC2A9 gene, is associated with carotid intima-media thickness despite significant associations between SUA levels and several clinical outcomes, thereby lending support to the hypothesis of a link between SUA and cardiovascular disease.

Genetic variants in ALDH1L1 and GLDC influence the serine-to-glycine ratio in Hispanic children

BACKGROUND

Glycine is a proteogenic amino acid that is required for numerous metabolic pathways, including purine, creatine, heme, and glutathione biosynthesis. Glycine formation from serine, catalyzed by serine hydroxy methyltransferase, is the major source of this amino acid in humans. Our previous studies in a mouse model have shown a crucial role for the 10-formyltetrahydrofolate dehydrogenase enzyme in serine-to-glycine conversion.

OBJECTIVES

We sought to determine the genomic influence on the serine-glycine ratio in 803 Hispanic children from 319 families of the Viva La Familia cohort.

METHODS

We performed a genome-wide association analysis for plasma serine, glycine, and the serine-glycine ratio in Sequential Oligogenic Linkage Analysis Routines while accounting for relationships among family members.

RESULTS

All 3 parameters were significantly heritable (h2 = 0.22-0.78; P < 0.004). The strongest associations for the serine-glycine ratio were with single nucleotide polymorphisms (SNPs) in aldehyde dehydrogenase 1 family member L1 (ALDH1L1) and glycine decarboxylase (GLDC) and for glycine with GLDC (P < 3.5 × 10-8; effect sizes, 0.03-0.07). No significant associations were found for serine. We also conducted a targeted genetic analysis with ALDH1L1 exonic SNPs and found significant associations between the serine-glycine ratio and rs2886059 (β = 0.68; SE, 0.25; P = 0.006) and rs3796191 (β = 0.25; SE, 0.08; P = 0.003) and between glycine and rs3796191 (β = -0.08; SE, 0.02; P = 0.0004). These exonic SNPs were further associated with metabolic disease risk factors, mainly adiposity measures (P < 0.006). Significant genetic and phenotypic correlations were found for glycine and the serine-glycine ratio with metabolic disease risk factors, including adiposity, insulin sensitivity, and inflammation-related phenotypes [estimate of genetic correlation = -0.37 to 0.35 (P < 0.03); estimate of phenotypic correlation = -0.19 to 0.13 (P < 0.006)]. The significant genetic correlations indicate shared genetic effects among glycine, the serine-glycine ratio, and adiposity and insulin sensitivity phenotypes.

CONCLUSIONS

Our study suggests that ALDH1L1 and GLDC SNPs influence the serine-to-glycine ratio and metabolic disease risk.

Association between glucokinase regulator gene polymorphisms and serum uric acid levels in Taiwanese adolescents

The glucokinase regulator gene (GCKR) is located on chromosome 2p23. It plays a crucial role in maintaining plasma glucose homeostasis and metabolic traits. Recently, genome-wide association studies have revealed a positive association between hyperuricemia and GCKR variants in adults. This study investigated this genetic association in Taiwanese adolescents. Data were collected from our previous cross-sectional study (Taipei Children Heart Study). The frequencies of various genotypes (CC, CT, and TT) or alleles (C and T) of the GCKR intronic single-nucleotide polymorphism (SNP) rs780094 and the coding SNP rs1260326 (Pro446Leu, a common 1403C-T transition) were compared between a total of 968 Taiwanese adolescents (473 boys, 495 girls) with hyperuricemia or normal uric acid levels on the basis of gender differences. Logistic and linear regression analyses explored the role of GCKR in abnormal uric acid (UA) levels. Boys had higher UA levels than girls (6.68 ± 1.29 and 5.23 ± 0.95 mg/dl, respectively, p < 0.001). The analysis of both SNPs in girls revealed that the T allele was more likely to appear in patients with hyperuricemia than the C allele. After adjusting for confounders, the odds ratio (OR) for hyperuricemia incidence in the TT genotype was 1.75 (95% confidence interval [CI] 1.02–3.00), which was higher than that in the C allele carriers in rs1260326 in the girl population. Similarly, the TT genotypes had a higher risk of hyperuricemia, with an OR of 2.29 (95% CI 1.11–4.73) for rs1260326 and 2.28 (95% CI 1.09–4.75) for rs780094, than the CC genotype in girl adolescents. The T (Leu446) allele of GCKR rs1260326 polymorphism is associated with higher UA levels in Taiwanese adolescent girls.

Gout prevalence in the Hmong: a prime example of health disparity and the role of community-based genetic research

Individuals of distinct Asian backgrounds are commonly aggregated as Asian, which could mask the differences in the etiology and prevalence of health conditions in the different Asian subgroups. The Hmong are a growing Asian subgroup in the United States with a higher prevalence of gout and gout-related comorbidities than non-Hmong. Genetic explorations in the Hmong suggest a higher prevalence of genetic polymorphisms associated with an increased risk of hyperuricemia and gout. History of immigration, acculturation, lifestyle factors, including dietary and social behavioral patterns, and the use of traditional medicines in the Hmong community may also increase the risk of developing gout and lead to poor gout management outcomes. Engaging minorities such as the Hmong population in biomedical research is a needed step to reduce the burden of health disparities within their respective communities, increase diversity in genomic studies, and accelerate the adoption of precision medicine to clinical practice.

Genetic variants and physical activity interact to affect bone density in Hispanic children

Background

Our aim was to investigate if moderate to vigorous physical activity (MVPA), calcium intake interacts with bone mineral density (BMD)-related single nucleotide polymorphisms (SNPs) to influence BMD in 750 Hispanic children (4-19y) of the cross-sectional Viva La Familia Study.

Methods

Physical activity and dietary intake were measured by accelerometers and multiple-pass 24 h dietary recalls, respectively. Total body and lumbar spine BMD were measured by dual energy X-ray absorptiometry. A polygenic risk score (PRS) was computed based on SNPs identified in published literature. Regression analysis was conducted with PRSs, MVPA and calcium intake with total body and lumbar spine BMD.

Results

We found evidence of statistically significant interaction effects between the PRS and MVPA on total body BMD and lumbar spine BMD (p < 0.05). Higher PRS was associated with a lower total body BMD (β = − 0.040 ± 0.009, p = 1.1 × 10^− 5) and lumbar spine BMD (β = − 0.042 ± 0.013, p = 0.0016) in low MVPA group, as compared to high MVPA group (β = − 0.015 ± 0.006, p = 0.02; β = 0.008 ± 0.01, p = 0.4, respectively).

Discussion

The study indicated that calcium intake does not modify the relationship between genetic variants and BMD, while it implied physical activity interacts with genetic variants to affect BMD in Hispanic children. Due to limited sample size of our study, future research on gene by environment interaction on bone health and functional studies to provide biological insights are needed.

Conclusions

Bone health in Hispanic children with high genetic risk for low BMD is benefitted more by MVPA than children with low genetic risk. Our results may be useful to predict disease risk and tailor dietary and physical activity advice delivery to people, especially children.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-021-02537-y.

Urate crystal deposition in hyperuricemic children: a dual energy computed tomography study

INTRODUCTION

The incidence of hyperuricemia (HUA) at younger ages is increasing along the coastal regions of China. This study aimed to compare the frequency of dual energy CT (DECT) urate crystal deposition between symptomatic hyperuricemic children and asymptomatic hyperuricemic children.

MATERIAL AND METHODS

Fifty-six hyperuricemic children were divided into a Joint Group (n = 33) and an Asymptomatic Group (n = 23) according to whether they had a history of arthritis symptoms, which includes rapid onset monoarthritis with intense pain and swelling. We analyzed DECT scans of their feet from the Joint Group and the Asymptomatic Group and compared their clinical features.

RESULTS

DECT urate deposits were observed in 28/33 (84.8%) children with symptomatic HUA and 14/23 (60.9%) with asymptomatic HUA. We found 60 areas of urate deposition in the Joint Group; DECT urate crystal deposition was most frequently observed in the first metatarsophalangeal (MTP) joint (30.0%), ankle joint (15.0%), and calcaneus (13.3%). 39 urate deposits were found in the Asymptomatic Group; DECT urate crystal deposition was most frequently observed in the calcaneus (25.6%), the first MTP joint (17.9%), and the first phalanx (15.4%).

CONCLUSIONS

Urate deposition can occur in children with HUA, and these deposits occur more frequently in hyperuricemic children with a history of arthritis symptoms. Also, the urate deposition in the first MTP joint and calcaneus was more prevalent than in other joints. It is important to give more attention to hyperuricemic children.

Uric Acid and Hypertension: An Update With Recommendations

The association between increased serum urate and hypertension has been a subject of intense controversy. Extracellular uric acid drives uric acid deposition in gout, kidney stones, and possibly vascular calcification. Mendelian randomization studies, however, indicate that serum urate is likely not the causal factor in hypertension although it does increase the risk for sudden cardiac death and diabetic vascular disease. Nevertheless, experimental evidence strongly suggests that an increase in intracellular urate is a key factor in the pathogenesis of primary hypertension. Pilot clinical trials show beneficial effect of lowering serum urate in hyperuricemic individuals who are young, hypertensive, and have preserved kidney function. Some evidence suggest that activation of the renin-angiotensin system (RAS) occurs in hyperuricemia and blocking the RAS may mimic the effects of xanthine oxidase inhibitors. A reduction in intracellular urate may be achieved by lowering serum urate concentration or by suppressing intracellular urate production with dietary measures that include reducing sugar, fructose, and salt intake. We suggest that these elements in the western diet may play a major role in the pathogenesis of primary hypertension. Studies are necessary to better define the interrelation between uric acid concentrations inside and outside the cell. In addition, large-scale clinical trials are needed to determine if extracellular and intracellular urate reduction can provide benefit hypertension and cardiometabolic disease.

Genetic variants affecting bone mineral density and bone mineral content at multiple skeletal sites in Hispanic children

CONTEXT

Osteoporosis is a major public health burden with significant economic costs. However, the correlates of bone health in Hispanic children are understudied.

OBJECTIVE

We aimed to identify genetic variants associated with bone mineral density (BMD) and bone mineral content (BMC) at multiple skeletal sites in Hispanic children.

METHODS

We conducted a cross-sectional genome-wide linkage analysis, genome-wide and exome-wide association analysis of BMD and BMC. The Viva La Familia Study is a family-based cohort with a total of 1030 Hispanic children (4-19 years old at baseline) conducted in Houston, TX. BMD and BMC were measured by Dual-energy X-ray absorptiometry.

RESULTS

Significant heritability were observed for BMC and BMD at multiple skeletal sites ranging between 44 and 68% (P < 2.8 × 10-9). Significant evidence for linkage was found for BMD of pelvis and left leg on chromosome 7p14, lumbar spine on 20q13 and left rib on 6p21, and BMC of pelvis on chromosome 20q12 and total body on 14q22-23 (logarithm of odds score > 3). We found genome-wide significant association between BMC of right arm and rs762920 at PVALB (P = 4.6 × 10-8), and between pelvis BMD and rs7000615 at PTK2B (P = 7.4 × 10-8). Exome-wide association analysis revealed novel association of variants at MEGF10 and ABRAXAS2 with left arm and lumber spine BMC, respectively (P < 9 × 10-7).

CONCLUSIONS

We identified novel loci associated with BMC and BMD in Hispanic children, with strongest evidence for PTK2B. These findings provide better understanding of bone genetics and shed light on biological mechanisms underlying BMD and BMC variation.

Fine mapping and identification of serum urate loci in American Indians: The Strong Heart Family Study

While studies have reported genetic loci affecting serum urate (SU) concentrations, few studies have been conducted in minority populations. Our objective for this study was to identify genetic loci regulating SU in a multigenerational family-based cohort of American Indians, the Strong Heart Family Study (SHFS). We genotyped 162,718 single nucleotide polymorphisms (SNPs) in 2000 SHFS participants using an Illumina MetaboChip array. A genome-wide association analysis of SU was conducted using measured genotype analysis approach accounting for kinships in SOLAR, and meta-analysis in METAL. Our results showed strong association of SU with rs4481233, rs9998811, rs7696092 and rs13145758 (minor allele frequency (MAF) = 25-44%; P < 3 × 10-14) of solute carrier family 2, member 9 (SLC2A9) and rs41481455, rs2231142 and rs1481012 (MAF = 29%; p < 3 × 10-9) of ATP-binding cassette protein, subfamily G, member 2 (ABCG2). Carriers of G alleles of rs9998811, rs4148155 and rs1481012 and A alleles of rs4481233, rs7696092 and rs13145758 and rs2231142 had lower SU concentrations as compared to non-carriers. Genetic analysis of SU conditional on significant SLC2A9 and ABCG2 SNPs revealed new loci, nucleobindin 1 (NUCB1) and neuronal PAS domain protein 4 (NPAS4) (p <6× 10-6). To identify American Indian-specific SNPs, we conducted targeted sequencing of key regions of SLC2A9. A total of 233 SNPs were identified of which 89 were strongly associated with SU (p < 7.1 × 10-10) and 117 were American Indian specific. Analysis of key SNPs in cohorts of Mexican-mestizos, European, Indian and East Asian ancestries showed replication of common SNPs, including our lead SNPs. Our results demonstrate the association of SU with uric acid transporters in a minority population of American Indians and potential novel associations of SU with neuronal-related genes which warrant further investigation.

Heterogeneity in Metabolic Responses to Dietary Fructose

Consumption of fructose has dramatically increased in past few decades in children and adults. Increasing evidence indicates that added sugars (particularly fructose) have adverse effects on metabolism and lead to numerous cardiometabolic diseases. Although both fructose and glucose are components of sucrose and high fructose corn syrup, the sugars have different metabolic fates in the human body and the effects of fructose on health are thought to be more adverse than glucose. Studies have also shown that the metabolic effects of fructose differ between individuals based on their genetic background, as individuals with specific SNPs and risk alleles seem to be more susceptible to the adverse metabolic effects of fructose. The current review discusses the metabolic effects of fructose on key complex diseases and discusses the heterogeneity in metabolic responses to dietary fructose in humans.

Adolescent obesity in the past decade: A systematic review of genetics and determinants of food choice

Background and purpose:

As the incidence of global obesity increases, concerns about adverse health outcomes in adolescents continues to rise. The complexity and expense of this problem require early recognition and specific preventive treatments. Knowledge of genetics and determinants of food choices contributing to adolescent obesity warrants further examination. The primary goal was to appraise the literature from the past decade (2007–2017) on the current state of food choice and genetic determinants of adolescent overweight/obesity in the United States. The secondary goal was to determine trends in the literature and areas for future research.

Methods:

A systematic review of research studies in the United States from 2007 to 2017 was completed. Database searches were conducted using CINAHL, Embase, PsycINFO, PsycArticles, PubMed, Scopus, Academic Search Complete, Web of Science, BIOSIS, and the Cochrane Library. A total of 535 studies were selected. Of these, 283 studies focused on determinants of food choices and 165 studies focused on genetic factors.

Conclusions:

A total of 41 full-text articles included in this literature review contained studies limited exclusively to adolescents. Stress factors related to food choices demonstrated a new trend being explored. The need for precision health, the application of genetic information, could uncover ways food choices affect adolescent obesity.

Implications for practice:

The etiology of adolescent obesity requires that nurses gain knowledge of genetics and food choice determinants to inform personalized treatments for adolescents, which may establish effective interventions that promote healthy weight achievement.

Elevated Interleukin 1β and Interleukin 6 Levels in the Serum of Children With Hyperuricemia

PURPOSES

The aim of this study was to investigate the serum levels and clinical significance of interleukin 1β (IL-1β) and IL-6 in children with hyperuricemia (HUA).

METHODS

We included 71 children with HUA and 71 children with no HUA as control subjects. Children with HUA were divided into groups I and II according to whether they had a history of acute gout-like attacks (including sudden monoarthritis of rapid onset with intense pain and swelling). Group I was examined twice (A, in the acute phase; B, in the remission phase). Serum IL-1β and IL-6 levels were measured by enzyme-linked immunosorbent assay.

RESULTS

Serum IL-1β and IL-6 levels were increased in children with HUA and were overall statistically different from the control group (P < 0.05, respectively). Serum IL-1β and IL-6 were significantly higher in group IA in comparison with group IB, group II, and control subjects (P < 0.05, respectively), as well as in groups IB and II compared with control subjects (P < 0.05, respectively). In group IB, the serum IL-1β and IL-6 concentrations were higher than those in group II, but there were no statistical differences (P > 0.05). In addition, in children with HUA, serum IL-1β and IL-6 levels were positively associated with white blood cell count, neutrophil count, monocyte count, uric acid levels, erythrocyte sedimentation rate, C-reactive protein, blood urea nitrogen, and serum creatinine levels (all P < 0.05), but were not associated with triglycerides, total cholesterol, low-density lipoprotein cholesterol, or high-density lipoprotein cholesterol levels (all P > 0.05).

CONCLUSION

IL-1β and IL-6 levels are increased in children with hyperuricemia, even if they have not had acute gout. Further studies are necessary to fully characterize the significance of IL-1β and IL-6 found in HUA children, and whether they could be correlated with long-term prognosis.

Influence of Genetic and Non-Genetic Risk Factors for Serum Uric Acid Levels and Hyperuricemia in Mexicans

Risk of hyperuricemia is modified by genetic and environmental factors. Our aim was to identify factors associated with serum uric acid levels and hyperuricemia in Mexicans. A pilot Genome-wide association study GWAS was performed in a subgroup of participants (n = 411) from the Health Workers Cohort Study (HWCS). Single nucleotide polymorphisms (SNPs) associated with serum uric acid levels were validated in all the HWCS participants (n = 1939) and replicated in independent children (n = 1080) and adult (n = 1073) case-control studies. The meta-analysis of the whole HWCS and replication samples identified three SLC2A9 SNPs: rs1014290 (p = 2.3 × 10⁻⁶⁴), rs3775948 (p = 8.2 × 10⁻⁶⁴) and rs11722228 (p = 1.1 × 10⁻¹⁷); and an ABCG2 missense SNP, rs2231142 (p = 1.0 × 10⁻¹⁸). Among the non-genetic factors identified, the visceral adiposity index, smoking, the metabolic syndrome and its components (waist circumference, blood pressure, glucose and hyperlipidemia) were associated with increased serum uric acid levels and hyperuricemia (p < 0.05). Among the female HWCS participants, the odds ratio for hyperuricemia was 1.24 (95% CI, 1.01–1.53) per unit increase in soft drink consumption. As reported in other studies, our findings indicate that diet, adiposity and genetic variation contribute to the elevated prevalence of hyperuricemia in Mexico.

The impact of dysfunctional variants of ABCG2 on hyperuricemia and gout in pediatric-onset patients

BACKGROUND

ABCG2 is a high-capacity urate transporter that plays a crucial role in renal urate overload and extra-renal urate underexcretion. Previous studies have suggested an association between hyperuricemia and gout susceptibility relative to dysfunctional ABCG2 variants, with rs2231142 (Q141K) being the most common. In this study, we analyzed the ABCG2 gene in a hyperuricemia and gout cohort focusing on patients with pediatric-onset, i.e., before 18 years of age.

METHOD

The cohort was recruited from the Czech Republic (n = 234) and consisted of 58 primary hyperuricemia and 176 gout patients, with a focus on pediatric-onset patients (n = 31, 17 hyperuricemia/14 gouts); 115 normouricemic controls were used for comparison. We amplified, sequenced, and analyzed 15 ABCG2 exons. The chi-square goodness-of-fit test was used to compare minor allele frequencies (MAF), and the log-rank test was used to compare empirical distribution functions.

RESULTS

In the pediatric-onset cohort, two common (p.V12M, p.Q141K) and three very rare (p.K360del, p.T421A, p.T434M) allelic ABCG2 variants were detected. The MAF of p.Q141K was 38.7% compared to adult-onset MAF 21.2% (OR = 2.4, P = 0.005), to the normouricemic controls cohort MAF 8.5% (OR = 6.8, P <  0.0001), and to the European population MAF 9.4% (OR = 5.7, P <  0.0001). The MAF was greatly elevated not only among pediatric-onset gout patients (42.9%) but also among patients with hyperuricemia (35.3%). Most (74%) of the pediatric-onset patients had affected family members (61% were first-degree relatives).

CONCLUSION

Our results show that genetic factors affecting ABCG2 function should be routinely considered in a hyperuricemia/gout diagnosis, especially in pediatric-onset patients. Genotyping of ABCG2 is essential for risk estimation of gout/hyperuricemia in patients with very early-onset and/or a family history.

The Daniel K. Inouye College of Pharmacy Scripts: Perspectives on the Epidemiology of Gout and Hyperuricemia

Gout is the most common inflammatory arthritic condition affecting more men than women. Hyperuricemia and the deposition of urate crystals into the joints are the hallmarks of gout. The prevalence of gout and hyperuricemia is rising in the United States and world-wide possibly due to the aging population, comorbidities, and other lifestyle factors. Gout and serum uric acid (SUA) levels are highly heritable, underscoring the role of genetics on disease risk and possibly the racial disparities in gout prevalence. However, high consumption of high fructose corn syrup, alcohol, select dietary lifestyles, and use of diuretics are associated with higher SUA levels and increased risk for developing gout. Adopting healthy diet and lifestyle modifications can lower SUA levels. Nonetheless, diet-based approaches for the management of gout should remain a secondary approach to urate lowering therapy.

Long-term effects of the SLC2A9 G844A and SLC22A12 C246T variants on serum uric acid concentrations in children

BACKGROUND

We evaluated the effects of two single-nucleotide polymorphisms on UA concentrations in the first decade of life using repeated-measures data.

METHODS

We included all subjects who were followed-up at least once and for whom we had both UA and genotypic data (i.e., 375, 204, 307, and 363 patients aged 3, 5, 7, and 9 years, respectively). All participated in the Ewha Birth and Growth Cohort study. We used a mixed model analysis to estimate the longitudinal association of serum UA concentration due to the rs3825017 (SLC22A12 c. 246C > T) and rs16890979 (SLC2A9 c. 844G > A) genotypes.

RESULTS

Overall, the tracking coefficient of UA concentrations in children 3 to 9 years of age was 0.31, and was higher in boys than in girls (0.34 vs. 0.29, respectively). Regarding individual variance, serum UA concentrations decreased as age increased (β = - 0.07, p < 0.05), but there were no significant differences by sex. The effects of rs3825017 on UA concentration were significant in boys, but not in girls. Boys with the T allele of rs3825017 had higher concentrations than their counterparts regardless of the time of follow-up. The rs16890979 genotypes were not significantly associated with serum UA concentration in either sex.

CONCLUSION

This study showed that rs3825017 in the SLC22A12 gene was associated with UA concentration in childhood.

An Intron Variant of SLC2A9 Increases the Risk for Type 2 Diabetes Mellitus Complicated with Hyperuricemia in Chinese Male Population

BACKGROUND

The aim of this study was to explore the associations of haplotypes of the glucose transporter 9 (SLC2A9) genes with type 2 diabetes mellitus (T2DM) complicated with hyperuricemia (HUA).

METHODS

Overall, 608 Chinese males, enrolled from the Affiliated Hospital of Medical College of Qingdao University in 2009-2012, were genotyped. The subjects included 167 withT2DM (average age of onset (58.07±11.82 yr), 198 with HUA subjects (average age of onset (39.20±9.73) yr), 115 with T2DM complicated with HUA (average age of onset (51.24±10.09) yr), and 128 control subjects (average age (41.92±10.01) yr). Patients genotypes of the SNPs; including rs734553 was determined by PCR method. Each genotype was regressed assuming the co-dominant, dominant and the recessive models of inheritance with covariates of duration of total glucose, uric acid, urea nitrogen, triglyceride, cholesterol, and creatinine levels.

RESULTS

Chi-square test revealed that rs734553polymorphism was both significantly associated with HUA as well as T2DM complicated HUA, but not with pure T2DM. After adjustment for age and gender, analysis showed that people with C allele had higher risk of HUA and T2DM complicated HUA than those without C allele. And none of the subjects had the homozygous genotype for SLC2A9 (CC).

CONCLUSION

The SLC2A9 mutation increases the risk for T2DM complicated HUA in Chinese population, which suggested that intron variants between two relatively conserved exons could also be associated with diseases. In patients of T2DM complicated with HUA, the diagnosis and detection of SLC2A9 gene variants should be caused enough attention.

Genome-wide association analysis identifies multiple loci associated with kidney disease-related traits in Korean populations

Chronic kidney disease (CKD) is an important social health problem characterized by a decrease in the kidney glomerular filtration rate (GFR). In this study, we analyzed genome-wide association studies for kidney disease-related traits using data from a Korean adult health screening cohort comprising 7,064 participants. Kidney disease-related traits analyzed include blood urea nitrogen (BUN), serum creatinine, estimated GFR, and uric acid levels. We detected two genetic loci (SLC14A2 and an intergenic region) and 8 single nucleotide polymorphisms (SNPs) associated with BUN, 3 genetic loci (BCAS3, C17orf82, ALDH2) and 6 SNPs associated with serum creatinine, 3 genetic loci (BCAS3, C17orf82/TBX2, LRP2) and 7 SNPs associated with GFR, and 14 genetic loci (3 in ABCG2/PKD2, 2 in SLC2A9, 3 in intergenic regions on chromosome 4; OTUB1, NRXN2/SLC22A12, CDC42BPG, RPS6KA4, SLC22A9, and MAP4K2 on chromosome 11) and 84 SNPs associated with uric acid levels. By comparing significant genetic loci associated with serum creatinine levels and GFR, rs9895661 in BCAS3 and rs757608 in C17orf82 were simultaneously associated with both traits. The SNPs rs11710227 in intergenic regions on chromosome 3 showing significant association with BUN is newly discovered. Genetic variations of multiple gene loci are associated with kidney disease-related traits, and differences in associations between kidney disease-related traits and genetic variation are dependent on the population. The meanings of the mutations identified in this study will need to be reaffirmed in other population groups in the future.

Heritability and Genome-Wide Association Analyses of Serum Uric Acid in Middle and Old-Aged Chinese Twins

Serum uric acid (SUA), as the end product of purine metabolism, has proven emerging roles in human disorders. Here based on a sample of 379 middle and old-aged Chinese twin pairs, we aimed to explore the magnitude of genetic impact on SUA variation by performing sex-limitation twin modeling analyses and further detect specific genetic variants related to SUA by conducting a genome-wide association study. Monozygotic (MZ) twin correlation for SUA level (rMZ = 0.56) was larger than for dizygotic (DZ) twin correlation (rDZ = 0.39). The common effects sex-limitation model provided the best fit with additive genetic parameter (A) accounting for 46.3%, common or shared environmental parameter (C) accounting for 26.3% and unique/nonshared environmental parameter (E) accounting for 27.5% for females and 29.9, 33.1, and 37.0% for males, respectively. Although no SUA-related genetic variants reached genome-wide significance level, 25 SNPs were suggestive of association (P < 1 × 10-5). Most of the SNPs were located in an intronic region and detected to have regulatory effects on gene transcription. The cell-type specific enhancer of skeletal muscle was detected which has been reported to implicate SUA. Two promising genetic regions on chromosome 17 around rs2253277 and chromosome 14 around rs11621523 were found. Gene-based analysis found 167 genes nominally associated with SUA level (P < 0.05), including PTGR2, ENTPD5, well-known SLC2A9, etc. Enrichment analysis identified one pathway of transmembrane transport of small molecules and 20 GO gene sets involving in ion transport, transmembrane transporter activity, hydrolase activity acting on acid anhydrides, etc. In conclusion, SUA shows moderate heritability in women and low heritability in men in the Chinese population and genetic variations are significantly involved in functional genes and regulatory domains that mediate SUA level. Our findings provide clues to further elucidate molecular physiology of SUA homeostasis and identify new diagnostic biomarkers and therapeutic targets for hyperuricemia and gout.

Hyperuricemia, Acute and Chronic Kidney Disease, Hypertension, and Cardiovascular Disease: Report of a Scientific Workshop Organized by the National Kidney Foundation

Urate is a cause of gout, kidney stones, and acute kidney injury from tumor lysis syndrome, but its relationship to kidney disease, cardiovascular disease, and diabetes remains controversial. A scientific workshop organized by the National Kidney Foundation was held in September 2016 to review current evidence. Cell culture studies and animal models suggest that elevated serum urate concentrations can contribute to kidney disease, hypertension, and metabolic syndrome. Epidemiologic evidence also supports elevated serum urate concentrations as a risk factor for the development of kidney disease, hypertension, and diabetes, but differences in methodologies and inpacts on serum urate concentrations by even subtle changes in kidney function render conclusions uncertain. Mendelian randomization studies generally do not support a causal role of serum urate in kidney disease, hypertension, or diabetes, although interpretation is complicated by nonhomogeneous populations, a failure to consider environmental interactions, and a lack of understanding of how the genetic polymorphisms affect biological mechanisms related to urate. Although several small clinical trials suggest benefits of urate-lowering therapies on kidney function, blood pressure, and insulin resistance, others have been negative, with many trials having design limitations and insufficient power. Thus, whether uric acid has a causal role in kidney and cardiovascular diseases requires further study.

Markers of Iron Status Are Associated with Risk of Hyperuricemia among Chinese Adults: Nationwide Population-Based Study

Background: Elevated serum uric acid (SUA) involved in iron metabolism, has been increasingly recognized as a risk factor for gout and cardiovascular diseases. The objective of this study was to examine the associations between markers of iron status with risk of hyperuricemia (HU) in Chinese adult population. Methods: Data were extracted from the 2009 wave of the China Health and Nutrition Survey, consisting of 7946 apparently healthy adults. Serum ferritin (SF), transferrin, soluble transferrin receptors (sTfR), hemoglobin (Hb), high-sensitivity C-reactive protein (hs-CRP), and SUA were measured. Diet was assessed with three consecutive 24 h recalls. Demographic characteristics, smoking status, alcohol consumption, and physical activities were investigated using a structured questionnaire. Multilevel mixed-effects models were constructed to estimate the associations of SF, transferrin, sTfR, and Hb with SUA and the risk of HU. Results: The crude prevalence of HU was 16.1%. SF, transferrin, and Hb levels were positively associated with SUA and the risk of HU after adjustment for cluster effects and potential confounders (all p-trend < 0.05). Compared with participants in the lowest quartile of SF, those in the highest quartile had significantly higher SUA concentrations (β = 0.899 mg/dL, 95% confidence interval (CI): 0.788, 1.010; p < 0.001) and higher risk of HU (odds ratio (OR) = 3.086, 95% CI: 2.450, 3.888; p < 0.001). Participants with the highest quartile of transferrin had significantly higher SUA concentrations (β = 0.488 mg/dL, 95% CI: 0.389, 0.587; p < 0.001) and higher risk of HU (OR: 1.900; 95% CI: 1.579, 2.286; p < 0.001) when compared with those with the lowest quartile. In male participants, those in the highest quartile of Hb had significantly higher risk of HU when compared to the reference group (OR: 1.401, 95% CI: 1.104, 1.777; p < 0.01); however, this association was not found in female participants (OR: 1.093; 95% CI: 0.821, 1.455; p = 0.544). Conclusion: SF, transferrin, and Hb levels were positively associated with the risk of HU, and additional studies are needed to confirm the findings, as well as to elucidate their underlying mechanisms.

Exome sequencing reveals novel genetic loci influencing obesity-related traits in Hispanic children

OBJECTIVE

To perform whole exome sequencing in 928 Hispanic children and identify variants and genes associated with childhood obesity.

METHODS

Single-nucleotide variants (SNVs) were identified from Illumina whole exome sequencing data using integrated read mapping, variant calling, and an annotation pipeline (Mercury). Association analyses of 74 obesity-related traits and exonic variants were performed using SeqMeta software. Rare autosomal variants were analyzed using gene-based association analyses, and common autosomal variants were analyzed at the SNV level.

RESULTS

(1) Rare exonic variants in 10 genes and 16 common SNVs in 11 genes that were associated with obesity traits in a cohort of Hispanic children were identified, (2) novel rare variants in peroxisome biogenesis factor 1 (PEX1) associated with several obesity traits (weight, weight z score, BMI, BMI z score, waist circumference, fat mass, trunk fat mass) were discovered, and (3) previously reported SNVs associated with childhood obesity were replicated.

CONCLUSIONS

Convergence of whole exome sequencing, a family-based design, and extensive phenotyping discovered novel rare and common variants associated with childhood obesity. Linking PEX1 to obesity phenotypes poses a novel mechanism of peroxisomal biogenesis and metabolism underlying the development of childhood obesity.

Genetic risk scores, sex and dietary factors interact to alter serum uric acid trajectory among African-American urban adults

Serum uric acid (SUA), a causative agent for gout among others, is affected by both genetic and dietary factors, perhaps differentially by sex. We evaluated cross-sectional (SUAbase) and longitudinal (SUArate) associations of SUA with a genetic risk score (GRS), diet and sex. We then tested the interactive effect of GRS, diet and sex on SUA. Longitudinal data on 766 African-American urban adults participating in the Healthy Aging in Neighborhood of Diversity across the Lifespan study were used. In all, three GRS for SUA were created from known SUA-associated SNP (GRSbase (n 12 SNP), GRSrate (n 3 SNP) and GRStotal (n 15 SNP)). Dietary factors included added sugar, total alcohol, red meat, total fish, legumes, dairy products, caffeine and vitamin C. Mixed-effects linear regression models were conducted. SUAbase was higher among men compared with that among women, and increased with GRStotal tertiles. SUArate was positively associated with legume intake in women (γ=+0·14; 95 % CI +0·06, +0·22, P=0·001) and inversely related to dairy product intake in both sexes combined (γ=-0·042; 95 % CI -0·075, -0·009), P=0·010). SUAbase was directly linked to alcohol consumption among women (γ=+0·154; 95 % CI +0·046, +0·262, P=0·005). GRSrate was linearly related to SUArate only among men. Legume consumption was also positively associated with SUArate within the GRStotal's lowest tertile. Among women, a synergistic interaction was observed between GRSrate and red meat intake in association with SUArate. Among men, a synergistic interaction between low vitamin C and genetic risk was found. In sum, sex-diet, sex-gene and gene-diet interactions were detected in determining SUA. Further similar studies are needed to replicate our findings.

Genetic variation underlying renal uric acid excretion in Hispanic children: the Viva La Familia Study

Background

Reduced renal excretion of uric acid plays a significant role in the development of hyperuricemia and gout in adults. Hyperuricemia has been associated with chronic kidney disease and cardiovascular disease in children and adults. There are limited genome-wide association studies associating genetic polymorphisms with renal urate excretion measures. Therefore, we investigated the genetic factors that influence the excretion of uric acid and related indices in 768 Hispanic children of the Viva La Familia Study.

Methods

We performed a genome-wide association analysis for 24-h urinary excretion measures such as urinary uric acid/urinary creatinine ratio, uric acid clearance, fractional excretion of uric acid, and glomerular load of uric acid in SOLAR, while accounting for non-independence among family members.

Results

All renal urate excretion measures were significantly heritable (p <2 × 10⁻⁶) and ranged from 0.41 to 0.74. Empirical threshold for genome-wide significance was set at p <1 × 10⁻⁷. We observed a strong association (p < 8 × 10⁻⁸) of uric acid clearance with a single nucleotide polymorphism (SNP) in zinc finger protein 446 (ZNF446) (rs2033711 (A/G), MAF: 0.30). The minor allele (G) was associated with increased uric acid clearance. Also, we found suggestive associations of uric acid clearance with SNPs in ZNF324, ZNF584, and ZNF132 (in a 72 kb region of 19q13; p <1 × 10⁻⁶, MAFs: 0.28–0.31).

Conclusion

For the first time, we showed the importance of 19q13 region in the regulation of renal urate excretion in Hispanic children. Our findings indicate differences in inherent genetic architecture and shared environmental risk factors between our cohort and other pediatric and adult populations.

Electronic supplementary material

The online version of this article (doi:10.1186/s12881-016-0366-3) contains supplementary material, which is available to authorized users.

Blueberry Consumption Affects Serum Uric Acid Concentrations in Older Adults in a Sex-Specific Manner

Blueberries are rich in antioxidants and may protect against disease. Uric acid accounts for about 50% of the antioxidant properties in humans. Elevated levels of serum uric acid (SUA) or hyperuricemia is a risk factor for cardiovascular disease (CVD). The aim was to determine the effect of blueberries on SUA in older adults. Participants (n = 133, 65–80 years) experiencing mild cognitive impairment (MCI) were randomized in a double-blind 6-month clinical trial to either blueberry or placebo. A reference group with no MCI received no treatment. The mean (SD) SUA at baseline were 5.45 (0.9), 6.4 (1.3) and 5.8 (1.4) mg/dL in reference, placebo, and treatment groups, respectively. Baseline SUA was different in men and women (6.25 (1.1) vs. 5.35 (1.1), p = 0.001). During the first three months, SUA decreased in the blueberry group and was significantly different from the placebo group in both men and women (p < 0.0003). Sex-specific differences became apparent after 3 months, when only men showed an increase in SUA in the blueberry group and not in the placebo (p = 0.0006) between 3 and 6 months. At 6 months SUA had rebounded in both men and women and returned to baseline levels. Baseline SUA was correlated with CVD risk factors, waist circumference and triglycerides (p < 0.05), but differed by sex. Overall, 6 m SUA changes were negatively associated with triglycerides in men, but not in women. Group-wise association between 6 m SUA changes and CVD risk factors showed associations with diastolic blood pressure, triglycerides and high-density lipoprotein (HDL) cholesterol in women of the Blueberry group but not in men or any sex in the placebo group. In summary, blueberries may affect SUA and its relationship with CVD risk in a sex-specific manner.

GWAS and transcriptional analysis prioritize ITPR1 and CNTN4 for a serum uric acid 3p26 QTL in Mexican Americans

Background

The variation in serum uric acid concentrations is under significant genetic influence. Elevated SUA concentrations have been linked to increased risk for gout, kidney stones, chronic kidney disease, and cardiovascular disease whereas reduced serum uric acid concentrations have been linked to multiple sclerosis, Parkinson’s disease and Alzheimer’s disease. Previously, we identified a novel locus on chromosome 3p26 affecting serum uric acid concentrations in Mexican Americans from San Antonio Family Heart Study. As a follow up, we examined genome-wide single nucleotide polymorphism data in an extended cohort of 1281 Mexican Americans from multigenerational families of the San Antonio Family Heart Study and the San Antonio Family Diabetes/Gallbladder Study. We used a linear regression-based joint linkage/association test under an additive model of allelic effect, while accounting for non-independence among family members via a kinship variance component.

Results

Univariate genetic analysis indicated serum uric acid concentrations to be significant heritable (h² = 0.50 ± 0.05, p < 4 × 10⁻³⁵), and linkage analysis of serum uric acid concentrations confirmed our previous finding of a novel locus on 3p26 (LOD = 4.9, p < 1 × 10⁻⁵) in the extended sample. Additionally, we observed strong association of serum uric acid concentrations with variants in following candidate genes in the 3p26 region; inositol 1,4,5-trisphosphate receptor, type 1 (ITPR1), contactin 4 (CNTN4), decapping mRNA 1A (DCP1A); transglutaminase 4 (TGM4) and rho guanine nucleotide exchange factor (GEF) 26 (ARHGEF26) [p < 3 × 10⁻⁷; minor allele frequencies ranged between 0.003 and 0.42] and evidence of cis-regulation for ITPR1 transcripts.

Conclusion

Our results confirm the importance of the chromosome 3p26 locus and genetic variants in this region in the regulation of serum uric acid concentrations.

Global metabolomic profiling targeting childhood obesity in the Hispanic population

BACKGROUND

Metabolomics may unravel important biological pathways involved in the pathophysiology of childhood obesity.

OBJECTIVES

We aimed to 1) identify metabolites that differ significantly between nonobese and obese Hispanic children; 2) collapse metabolites into principal components (PCs) associated with obesity and metabolic risk, specifically hyperinsulinemia, hypertriglyceridemia, hyperleptinemia, and hyperuricemia; and 3) identify metabolites associated with energy expenditure and fat oxidation.

DESIGN

This trial was a cross-sectional observational study of metabolomics by using gas chromatography-mass spectrometry and ultrahigh-performance liquid chromatography-tandem mass spectrometry analyses performed on fasting plasma samples from 353 nonobese and 450 obese Hispanic children.

RESULTS

Branched-chained amino acids (BCAAs) (Leu, Ile, and Val) and their catabolites, propionylcarnitine and butyrylcarnitine, were significantly elevated in obese children. Strikingly lower lysolipids and dicarboxylated fatty acids were seen in obese children. Steroid derivatives were markedly higher in obese children as were markers of inflammation and oxidative stress. PC6 (BCAAs and aromatic AAs) and PC10 (asparagine, glycine, and serine) made the largest contributions to body mass index, and PC10 and PC12 (acylcarnitines) made the largest contributions to adiposity. Metabolic risk factors and total energy expenditure were associated with PC6, PC9 (AA and tricarboxylic acid cycle metabolites), and PC10. Fat oxidation was inversely related to PC8 (lysolipids) and positively related to PC16 (acylcarnitines).

CONCLUSIONS

Global metabolomic profiling in nonobese and obese children replicates the increased BCAA and acylcarnitine catabolism and changes in nucleotides, lysolipids, and inflammation markers seen in obese adults; however, a strong signature of reduced fatty acid catabolism and increased steroid derivatives may be unique to obese children. Metabolic flexibility in fuel use observed in obese children may occur through the activation of alternative intermediary pathways. Insulin resistance, hyperleptinemia, hypertriglyceridemia, hyperuricemia, and oxidative stress and inflammation evident in obese children are associated with distinct metabolomic profiles.