Gout Cases Research Articles

Genetic variation in WDR1 is associated with gout risk and gout-related metabolic indices in the Han Chinese population.

Gout is the most common form of inflammatory arthritis affecting men, and current evidence suggests that genetic factors contribute to its progression. As a previous study identified that WD40 repeat protein 1 (WDR1) is associated with gout in populations of European descent, we sought to investigate its relationship with this disease in the Han Chinese population. We genotyped six WDR1 single nucleotide polymorphisms in 143 gout cases and 310 controls using Sequenom MassARRAY technology. The SPSS 16.0 software was used to perform statistical analyses. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by unconditional logistic regression, with adjustments for age and gender. In an analysis using an allelic model, we identified that the minor alleles of rs3756230 (OR = 0.64, 95%CI = 0.450-0.911, P = 0.013) and rs12498927 (OR = 1.377, 95%CI = 1.037-1.831, P = 0.027) were associated with gout risk. In addition, we found that the "A/A" genotype of rs12498927 was associated with increased risk of gout under codominant (OR = 2.22, 95%CI = 1.12- 4.40, P = 0.042) and recessive models (OR = 2.24, 95%CI = 1.20-4.17, P = 0.012). We also determined the "A/G" genotype of rs12498927 to be significantly associated with higher urea levels in gout patients (P = 0.017). Our data shed new light on the association between genetic variations in the WDR1 gene and gout susceptibility in the Han Chinese population.

Bidirectional Association between Self-Reported Hypertension and Gout: The Singapore Chinese Health Study

It has been hypothesized that the association between hypertension and gout is bidirectional, however, few studies have examined this in a prospective cohort. We analyzed data from the Singapore Chinese Health Study (SCHS) follow-up I (1999–2004) and II (2006–2010) interviews, when both physician-diagnosed hypertension and gout were self-reported. We included participants with data for both follow-up interviews and who were free of heart disease, stroke and cancer at follow-up I. The analysis of hypertension and risk of gout included 31,137 participants when prevalent gout cases were excluded, while the analysis of gout and risk of hypertension included 20,369 participants when prevalent hypertension cases were excluded. Cox proportional hazards models were used to estimate multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs). The mean age at follow-up I was 60.1 (SD 7.3) years, and the average follow-up was 6.8 (SD 1.4) years. In the analysis of hypertension and risk of gout, 682 incident cases were identified. Compared to normotensive participants, hypertensive patients had an88% increased risk of developing gout (HR 1.88; 95% CI 1.61–2.21). In the parallel analysis, 5,450 participants reported to have newly diagnosed hypertension during follow-up. Compared to participants without gout, those with gout had an18% increased risk of developing hypertension (HR 1.18; 95% CI 1.02–1.37). The bidirectional association was stronger in normal weight adults compared to overweight/obese individuals (P interaction = 0.06 and 0.04, respectively). The hypertension to gout association was stronger in women compared to men (P interaction = 0.04), while the gout to hypertension association was evident in women but not in men (P interaction = 0.02). In conclusion, our results suggest that the hypertension-gout association is bidirectional in this cohort of Singapore Chinese adults. The potential interactions of the bidirectional association with obesity and sex deserve further investigations.

Multiplicative interaction of functional inflammasome genetic variants in determining the risk of gout

IntroductionThe acute gout flare results from a localised self-limiting innate immune response to monosodium urate (MSU) crystals deposited in joints in hyperuricaemic individuals. Activation of the caspase recruitment domain-containing protein 8 (CARD8) NOD-like receptor pyrin-containing 3 (NLRP3) inflammasome by MSU crystals and production of mature interleukin-1β (IL-1β) is central to acute gouty arthritis. However very little is known about genetic control of the innate immune response involved in acute gouty arthritis. Therefore our aim was to test functional single nucleotide polymorphism (SNP) variants in the toll-like receptor (TLR)-inflammasome-IL-1β axis for association with gout.Methods1,494 gout cases of European and 863 gout cases of New Zealand (NZ) Polynesian (Māori and Pacific Island) ancestry were included. Gout was diagnosed by the 1977 ARA gout classification criteria. There were 1,030 Polynesian controls and 10,942 European controls including from the publicly-available Atherosclerosis Risk in Communities (ARIC) and Framingham Heart (FHS) studies. The ten SNPs were either genotyped by Sequenom MassArray or by Affymetrix SNP array or imputed in the ARIC and FHS datasets. Allelic association was done by logistic regression adjusting by age and sex with European and Polynesian data combined by meta-analysis. Sample sets were pooled for multiplicative interaction analysis, which was also adjusted by sample set.ResultsEleven SNPs were tested in the TLR2, CD14, IL1B, CARD8, NLRP3, MYD88, P2RX7, DAPK1 and TNXIP genes. Nominally significant (P < 0.05) associations with gout were detected at CARD8 rs2043211 (OR = 1.12, P = 0.007), IL1B rs1143623 (OR = 1.10, P = 0.020) and CD14 rs2569190 (OR = 1.08; P = 0.036). There was significant multiplicative interaction between CARD8 and IL1B (P = 0.005), with the IL1B risk genotype amplifying the risk effect of CARD8.ConclusionThere is evidence for association of gout with functional variants in CARD8, IL1B and CD14. The gout-associated allele of IL1B increases expression of IL-1β – the multiplicative interaction with CARD8 would be consistent with a synergy of greater inflammasome activity (resulting from reduced CARD8) combined with higher levels of pre-IL-1β expression leading to increased production of mature IL-1β in gout.Electronic supplementary materialThe online version of this article (doi:10.1186/s13075-015-0802-3) contains supplementary material, which is available to authorized users.

Relationship between vitmin D receptor rs2228570 polymorphism and susceptibility to gout in Chinese Han male population

Objective To explore gene polymorphism of G/A genotype of FokⅠrs2228570(G/A)of vitamin D receptor(VDR)gene in Han male population of Chinese coastal area, and thus to investigate the relationship between the gene polymorphism of VDR and gout. Methods Altogether 504 gout patients and 523 healthy controls were enrolled. The possible association between the polymorphism of VDR rs2228570 and gout in Chinese coastal area was investigated and genotype frequencies and allelic frequencies were calculated by realtime PCR with Taqman® probe method. Hardy-Weinberg was used to verify the representativeness of the sample. Comparison between the groups were performed with χ2 test and t-test. Results The frequencies of GG, AG, and AA genotypes were 32.1%, 50.0%, and 17.9%, respectively among gout patients, while they were 27.9%, 50.5%, and 21.6% respectively among the controls. There was no statistically significant difference in VDR rs2228570 genotype frequencies between gout patients and controls(χ2=3.366, P>0.05). The allele frequencies of G and A in gout cases were different from those in the controls(57.1%, 42.9%; 53.2%, 46.8%; χ2=3.300, P>0.05). Conclusions Results of the present study suggest that the G/A genotype of VDR FokⅠrs2228570 of the VDR gene is not associated with gout in male population of Chinese coastal area. (Chin J Endocrinol Metab, 2015, 31: 316-319) Key words: Vitmin D receptor; Polymorphism, single Nucleotide; Gout

Lack of gene–diuretic interactions on the risk of incident gout: the Nurses’ Health Study and Health Professionals Follow-up Study

BackgroundDiuretic-induced gout might occur only among those with a genetic predisposition to hyperuricaemia, as suggested by a recent study with 108 self-reported gout cases.MethodsWe examined the role of urate genes...

Genome-wide association study of clinically defined gout identifies multiple risk loci and its association with clinical subtypes

ObjectiveGout, caused by hyperuricaemia, is a multifactorial disease. Although genome-wide association studies (GWASs) of gout have been reported, they included self-reported gout cases in which clinical information was insufficient. Therefore,...

Epidemiology and management of gout in Taiwan: a nationwide population study.

IntroductionGout is the most common inflammatory arthritis worldwide and is the only type of chronic arthritis that potentially can be ‘cured’. However, data on gout incidence, prevalence and management, assessed at multiple time points in the same population, are sparse, particularly in Asian populations. The aim of this study was to describe trends in the epidemiology of gout in the general population of Taiwan.MethodsThe National Health Insurance Research Database was used to identify patients with gout and to estimate the prevalence and incidence of gout for each calendar year from 2005 to 2010. The pattern of gout management was also examined.ResultsOf 23,371,362 beneficiaries in 2010, there were 1,458,569 prevalent and 56,595 incident cases of gout, giving a prevalence of 6.24% (95% confidence interval (CI), 6.23% to 6.25%) and an incidence of 2.74 (95% CI, 2.72 to 2.76) per 1,000 person-years. The annual percentage change (APC) of the standardised prevalence was −0.7% (95% CI, −1.7% to 0.3%; P = 0.14), suggesting that the prevalence of gout was essentially the same throughout the study period. However, The APC of incidence was −13.4 (95% CI, −16.1 to −10.6) between 2005 and 2007 and −2.1 (95% CI, −10.4 to 7.1) between 2007 and 2010. Regions with the highest prevalence and incidence were eastern coastal counties and offshore islets, where indigenous people are clustered. Among prevalent gout cases in 2010, only 22.93% (95% CI, 22.87% to 23.00%) were prescribed urate-lowering treatment (ULT), which remained unchanged between 2005 and 2010 at an APC of 0.0 (95% CI, −3.8 to 4.0). Uricosuric agents were more commonly prescribed than xanthine oxidase inhibitors in Taiwan.ConclusionsIn Taiwan, 1 in 16 people have gout. Whereas the incidence has decreased recently, the prevalence remains unchanged. Management of gout in Taiwan is poor, with only one in five affected people being treated with ULT.Electronic supplementary materialThe online version of this article (doi:10.1186/s13075-015-0522-8) contains supplementary material, which is available to authorized users.

Performance of classification criteria for gout in early and established disease

ObjectivesTo compare the sensitivity and specificity of different classification criteria for gout in early and established disease.MethodsThis was a cross-sectional study of consecutive rheumatology clinic patients with joint swelling in...

Common variant of ALPK1 is not associated with gout: a replication study.

Gout is one of the most kinds of common inflammatory arthritis as a consequence of hyperuricemia. Alpha-protein kinase 1 (ALPK1) gene locates in a gout-susceptibility locus on chromosome 4q21–31, and encodes ALPK1 protein which plays a pivotal role in the phosphorylation of myosin 1. In the previous genetic study of Taiwanese populations, 3 single nucleotide polymorphisms (SNPs), rs11726117, rs231247 and rs231253, in ALPK1 gene were reported to have a significant association with gout. However, no replication study has been performed to confirm this association. Therefore, we first conducted a replication study with clinically defined gout patients in a different population. Linkage disequilibrium (LD) analyzes of the 3 SNPs in ALPK1 revealed that these SNPs are in strong LD in a Japanese population. Among the 3 SNPs of ALPK1, rs11726117 (M861T) is the only missense SNP. Therefore, rs11726117 was genotyped in a Japanese population of 903 clinically defined gout cases and 1,302 controls, and was evaluated for a possible association with gout. The minor allele frequencies of rs11726117 were 0.26 and 0.25 in the case and control groups, respectively. The association analysis has not detected a significant association between rs11726117 and gout susceptibility in a Japanese population (p = 0.44). Because ABCG2, a major causative gene for gout, also locates in the gout-susceptibility locus on chromosome 4q, these findings suggest that among genes in a gout-susceptibility locus, not ALPK1 but ABCG2 could be important as a gout-susceptible gene.

Prevalence of gout with comorbidity aggregations in southern Taiwan

ObjectiveComorbidity is an important concern for chronic gout patients. We evaluated the relationship between comorbidity profiles and gout in Taiwan aborigines and Taiwanese Han. MethodsWe used the claims data from the Taiwan national health insurance database for 2004 to 2006. Physician-diagnosed gout and comorbidities were coded using the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM). Total sampling from Pingtung County of southern Taiwan included 37,482 aborigines (gout cases, n=3906 and controls, n=33,576) and 37,451 Han (gout cases, n=1115 and controls, n=36,336). ResultsIn 2006, the gout prevalences were 10.42% and 2.98% (prevalence ratio [PR]=3.50) in the aborigines and Han general populations, respectively. The prevalences of uric acid nephrolithiasis and tophi were higher in aborigines (0.42% and 0.30%, respectively) than in Han (0.09% and 0.04%, respectively). When stratified by comorbidity status, the prevalences of gout were 4.49% and 27.34% in aborigines and 1.52% and 9.44% in Han (approximate PR=3.00). Similarly, the prevalence ratios of gout in the comorbidity group, compared with the non-comorbidity group, were 6.09 in aborigines and 6.23 in Han. Multivariate odds ratios [ORs] showed that hypercholesterolemia, hyperglyceridemia, essential hypertension and renal insufficiency were the common comorbidities of gout (OR≥1.63); heart failure exerted a significant effect only in aborigines (OR=1.55). For five comorbidity factors, patients with multiple comorbidities had higher gout prevalence (maximum OR=12.90). ConclusionGout prevalence was higher in aborigines, both with and without comorbidities, than in Han. The comorbid diseases and comorbidity aggregations showed a substantial association with gout occurrence in both ethnicities.

THU0492 Association Analysis of 18 Recently Discovered Serum Urate Loci with Gout

BackgroundElevated serum urate levels are causal for gout. The first genome-wide association studies associated common genetic variation in 10 loci of stronger effect with serum urate. Predictably, the majority of...

THU0493 Association of the Toll-Like Receptor 4 (TLR4) Gene with Gout

BackgroundGout results from innate immune response to monosodium urate (MSU) crystals that form when serum urate is elevated. Identification of genetic risk factors for hyperuricemia and the MSU immune response...

Functional Polymorphisms of the ABCG2 Gene Are Associated with Gout Disease in the Chinese Han Male Population

BackgroundGout is a common type of arthritis that is characterized by hyperuricemia, tophi and joint inflammation. Genetic variations in the ABCG2 gene have been reported to influence serum uric acid levels and to participate in the pathogenesis of gout, but no further data have been reported in the Han Chinese population.MethodsPeripheral blood DNA was isolated from 352 male patients with gout and 350 gout-free normal male controls. High-resolution melting analysis and Sanger sequencing were performed to identify the genetic polymorphisms V12M, Q141K and Q126X in the ABCG2 gene. Genotype and haplotype analyses were utilized to determine the disease odds ratios (ORs). A prediction model for gout risk using ABCG2 protein function was established based on the genotype combination of Q126X and Q141K.ResultsFor Q141K, the A allele frequency was 49.6% in the gout patients and 30.9% in the controls (OR 2.20, 95% confidence interval (CI): 1.77–2.74, p = 8.99 × 10−13). Regarding Q126X, the T allele frequency was 4.7% in the gout patients and 1.7% in the controls (OR 2.91, 95% CI: 1.49–5.68, p = 1.57 × 10−3). The A allele frequency for V12M was lower (18.3%) in the gout patients than in the controls (29%) (OR 0.55, 95% CI 0.43–0.71, p = 2.55 × 10−6). In the order of V12M, Q126X and Q141K, the GCA and GTC haplotypes indicated increased disease risk (OR = 2.30 and 2.71, respectively). Patients with mild to severe ABCG2 dysfunction accounted for 78.4% of gout cases.ConclusionThe ABCG2 126X and 141K alleles are associated with an increased risk of gout, whereas 12M has a protective effect on gout susceptibility in the Han Chinese population. ABCG2 dysfunction can be used to evaluate gout risk.

65. Anxiety and Depression Comorbidity in Primary Care Gout: A Matched Retrospective Cohort Study

Background: Chronic conditions such as diabetes mellitus and cardiovascular disease are common in people with gout and are associated with poorer quality of life and higher mortality. However, our understanding of the role of psychological comorbidity in gout remains unclear. Frequent experience of severe pain, social isolation and strained family relationships may impact negatively on psychological health and influence health-seeking behaviour. This matched retrospective cohort study aimed to examine the association between gout and subsequent consultation for anxiety & depression in a UK primary care population. Methods: The study was undertaken using data from a general practice consultation database (CiPCA), gathered from nine general practices in North Staffordshire. Patients aged 18 years who consulted with gout between 2000 and 2008 were identified by Read code and each matched to 4 controls by age, gender, year of consultation and general practice. A consultation for either anxiety or depression, subsequent to the gout diagnosis, was defined from a relevant Read code gained between 2000 and 2011. Several other gout-related comorbidities (e.g. hypertension) were also recorded by Read code. Cox regression model was used to examine the association between gout and subsequent anxiety & depression consultation (new episodes), adjusting for age, gender, deprivation, year of consultation, general practice and comorbidities. Hazard ratio (HR) and 95% CI were reported for gout cases vs matched controls. Results: 1689 patients with gout were compared with 6,756 control patients. Mean age was 63 years (Standard deviation 16) and 24% were female. Of gout patients, 15.3% & 9.7% had consulted for anxiety & depression respectively, this was in comparison with 14.2% & 9.5% of the controls. Adjusted cox regression analysis found no association between gout and time to consultation for anxiety (HR 1.04, 95% CI 0.9, 1.2) or depression [0.88 (0.7, 1.1)] compared with controls. Across gout patients and matched controls, being younger and female was associated with a propensity to consult for anxiety & depression. With each year from first diagnosis (gout and controls), there was a trend of increasing consultation for anxiety. The presence of hypertension and alcoholism comorbidity was associated with an increased probability of consultation for anxiety & depression. Conclusion: Despite the psychological burden which gout may be expected to impart on patients, time to consultation for anxiety & depression in UK primary care was equivalent to matched controls. This may relate to the prolonged asymptomatic inter-critical period between gout attacks during which psychological burden may ease. However, as under-reporting of both anxiety & depression in primary care is common and the severity & disease characteristics of gout, anxiety & depression could not be established from medical records, further research considering these factors would be of benefit. Disclosure statement: The authors have declared no conflicts of interest.

Joint Effects of Alcohol Consumption and ABCG2 Q141K on Chronic Tophaceous Gout Risk

To investigate the joint effects of alcohol consumption and ABCG2 gene variants on tophaceous gout occurrence. The V12M (rs2231137), Q126X (rs72552713), and Q141K (rs2231142) of the ABCG2 gene were genotyped among controls, nontophaceous, and tophaceous gout cases in Taiwanese Han (n=446, 77, 177) and Taiwan Aborigines (n=1105, 203, 330). The missense variations V12M (C) and Q141K (T) significantly associated with tophaceous gout (p trend=4.08×10(-2), 9.00×10(-12) in Han; 1.81×10(-3), 9.34×10(-10) in Aborigines). The nonsense variation Q126X (T) exerted a significant effect only in Han (p=1.10×10(-2)), but not in Aborigines. In the prediction of tophaceous gout, the Q141K (T) OR were 1.51 in Han, 1.50 in Aborigines, and 1.55 (p=7.84×10(-5)) in pooled analysis when compared to nontophaceous gout. We found the joint effects of alcohol consumption and Q141K (T/T) highly associated with tophaceous gout (adjusted OR≥5.11; p≤7.78×10(-4)); specifically the ever drinkers carrying the Q141K (T/T; adjusted OR 25.05, p=9.21×10(-4) in Han; adjusted OR 14.87, p=1.08×10(-8) in Aborigines). Our findings showed alcohol consumption and ABCG2 Q141K, independently and jointly, associated with the risk of chronic tophaceous gout.

A Common Variant of Organic Anion Transporter 4 (OAT4/SLC22A11) Gene Is Associated with Renal Underexcretion Type Gout

Gout, a common disease, is a consequence of hyperuricemia, and increases the risks of hypertension, cardiovascular diseases, cerebrovascular diseases and renal failure. Gout can be classified into 3 types: the renal underexcretion (RUE) type, renal overload type and combined type. RUE type is a major type of gout; however, its genetic causes are still unclear. Since human organic anion transporter 4 (OAT4/SLC22A11) is expressed in the kidney and mediates urate transport, we investigated the effects of a common variant of OAT4/SLC22A11 on the susceptibility to gout. Five hundred and forty-five Japanese male gout cases and 1,115 male individuals as a control group were genotyped with rs17300741, a single nucleotide polymorphism in the OAT4/SLC22A11 gene. The association analysis of rs17300741 showed no significant association for all gout cases; however, there was a slight but significant association for RUE type gout cases (p = 0.049). These results also suggest that OAT4 contributes to urate transport at the apical membrane of renal proximal tubule cells in humans. Our findings make it clear for the first time that a common variant of OAT4/SLC22A11 is associated with RUE type gout, a major gout subtype.

A common variant of leucine-rich repeat-containing 16A (LRRC16A) gene is associated with gout susceptibility

Gout is a common disease resulting from hyperuricemia which causes acute arthritis. Recently, genome-wide association studies revealed an association between serum uric acid levels and a common variant of leucine-rich repeat-containing 16A (LRRC16A) gene. However, it remains to be clarified whether LRRC16A contributes to the susceptibility to gout. In this study, we investigated the relationship between rs742132 in LRRC16A and gout. A total of 545 Japanese male gout cases and 1,115 male individuals as a control group were genotyped. rs742132 A/A genotype significantly increased the risk of gout, conferring an odds ratio of 1.30 (95 % CI 1.05–1.60; p = 0.015). LRRC16A encodes a protein called capping protein ARP2/3 and myosin-I linker (CARMIL), which serves as an inhibitor of the actin capping protein (CP). CP is an essential element of the actin cytoskeleton, which binds to the barbed end of the actin filament and regulates its polymerization. In the apical membrane of proximal tubular cells in the human kidney, the urate-transporting multimolecular complex (urate transportsome) is proposed to consist of several urate transporters and scaffolding proteins, which interact with the actin cytoskeleton. Thus, if there is a CARMIL dysfunction and regulatory disability in actin polymerization, urate transportsome may be unable to operate appropriately. We have shown for the first time that CARMIL/LRRC16A was associated with gout, which could be due to urate transportsome failure.Electronic supplementary materialThe online version of this article (doi:10.1007/s13577-013-0081-8) contains supplementary material, which is available to authorized users.

CaseBook Challenges: Managing Gout, Hyperuricemia and Comorbidities—Dialogue with the Experts

The prevalence of gout and hyperuricemia are on the rise in the United States corresponding with an increase in risk factors for these conditions, such as obesity, metabolic syndrome, and the use of diuretics. A progressive disorder, untreated gout can be debilitating and result in tophi, chronic arthropathy, and recurrent kidney stones. Although joint aspiration is needed for a definitive diagnosis, the majority of patients are diagnosed presumptively based on medical history and presentation with characteristic signs and symptoms. Patients with gout also often have multiple comorbidities, and there is an increasing body of evidence that shows hyperuricemia is associated with incidence hypertension, diabetes, chronic kidney disease, and heart failure. Clinical strategies for the management of gout and hyperuricemia must include considerations for these and other common cardiometabolic and renal conditions. In addition to acute flare therapy and prophylaxis, the treatment of gout involves lowering serum uric acid (SUA) levels with the urate-lowering therapies (ULTs) allopurinol or febuxostat. Once begun, treatment with ULT is lifelong. However, inadequate dosing and patient nonadherence or intolerance to therapy often lead to treatment failure. Recent guidelines from the American College of Rheumatology stress tailoring therapy and target SUA level (traditionally <6 mg/dL, but lower levels may be needed for certain patients) based on gout severity and the presence of comorbid conditions. Because painful acute gout flares may result in trips to the emergency department and because the majority of gout cases are managed in primary care, it is important for clinicians practicing in these settings to be able to diagnose and treat this condition and communicate with patients to improve their understanding of the disease process and adherence to treatment.

A common missense variant of monocarboxylate transporter 9 (MCT9/SLC16A9) gene is associated with renal overload gout, but not with all gout susceptibility

Gout is a common disease caused by hyperuricemia, which shows elevated serum uric acid (SUA) levels. From a viewpoint of urate handling in humans, gout patients can be divided into those with renal overload (ROL) gout with intestinal urate underexcretion, and those with renal underexcretion (RUE) gout. Recent genome-wide association studies (GWAS) revealed an association between SUA and a variant in human monocarboxylate transporter 9 (MCT9/SLC16A9) gene. Although the function of MCT9 remains unclear, urate is mostly excreted via intestine and kidney where MCT9 expression is observed. In this study, we investigated the relationship between a variant of MCT9 and gout in 545 patients and 1,115 healthy volunteers. A missense variant of MCT9 (K258T), rs2242206, significantly increased the risk of ROL gout (p = 0.012), with odds ratio (OR) of 1.28, although it revealed no significant association with all gout cases (p = 0.10), non-ROL gout cases (p = 0.83), and RUE gout cases (p = 0.34). In any case groups and the control group, minor allele frequencies of rs2242206 were >0.40. Therefore, rs2242206 is a common missense variant and is revealed to have an association with ROL gout, indicating that rs2242206 relates to decreased intestinal urate excretion rather than decreased renal urate excretion. Our study provides clues to better understand the pathophysiology of gout as well as the physiological roles of MCT9.

Common dysfunctional variants in ABCG2 are a major cause of early-onset gout

Gout is a common disease which mostly occurs after middle age, but more people nowadays develop it before the age of thirty. We investigated whether common dysfunction of ABCG2, a high-capacity urate transporter which regulates serum uric acid levels, causes early-onset gout. 705 Japanese male gout cases with onset age data and 1,887 male controls were genotyped, and the ABCG2 functions which are estimated by its genotype combination were determined. The onset age was 6.5 years earlier with severe ABCG2 dysfunction than with normal ABCG2 function (P = 6.14 × 10−3). Patients with mild to severe ABCG2 dysfunction accounted for 88.2% of early-onset cases (twenties or younger). Severe ABCG2 dysfunction particularly increased the risk of early-onset gout (odds ratio 22.2, P = 4.66 × 10−6). Our finding that common dysfunction of ABCG2 is a major cause of early-onset gout will serve to improve earlier prevention and therapy for high-risk individuals.