Diabetes 53:870-873, 2004
© 2004 by the American Diabetes Association, Inc.
Analysis of the Type 2 Diabetes-Associated Single Nucleotide Polymorphisms in the Genes IRS1, KCNJ11, and PPARG2 in Type 1 Diabetes
Christina Eftychi1,
Joanna M.M. Howson1,
Bryan J. Barratt1,
Adrian Vella1,
Felicity Payne1,
Deborah J. Smyth1,
Rebecca C.J. Twells1,
Neil M. Walker1,
Helen E. Rance1,
Eva Tuomilehto-Wolf2,
Jaakko Tuomilehto2,3,
Dag E. Undlien4,
Kjersti S. Rønningen5,
Cristian Guja6,
Constantin Ionescu-Tîirgovi te6,
David A. Savage7, and
John A. Todd1
1 Juvenile Diabetes Research Foundation/Wellcome Trust Diabetes and Inflammation Laboratory, Cambridge Institute for Medical Research, University of Cambridge, Cambridge, U.K
2 Diabetes and Genetic Epidemiology Unit, National Public Health Institute, University of Helsinki, Helsinki, Finland
3 Department of Public Health, University of Helsinki, Helsinki, Finland
4 Institute of Medical Genetics, Ulleval University Hospital, University of Oslo, Oslo, Norway
5 Laboratory of Molecular Epidemiology, Division of Epidemiology, Norwegian Institute of Public Health, Oslo, Norway
6 Clinic of Diabetes, Institute of Diabetes, Nutrition and Metabolic Diseases, Bucharest, Romania
7 Department of Medical Genetics, Queens University Belfast, Belfast City Hospital, Belfast, Northern Ireland
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ABSTRACT
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It has been proposed that type 1 and 2 diabetes might share common pathophysiological pathways and, to some extent, genetic background. However, to date there has been no convincing data to establish a molecular genetic link between them. We have genotyped three single nucleotide polymorphisms associated with type 2 diabetes in a large type 1 diabetic family collection of European descent: Gly972Arg in the insulin receptor substrate 1 (IRS1) gene, Glu23Lys in the potassium inwardly-rectifying channel gene (KCNJ11), and Pro12Ala in the peroxisome proliferative-activated receptor 2 gene (PPARG2). We were unable to confirm a recently published association of the IRS1 Gly972Arg variant with type 1 diabetes. Moreover, KCNJ11 Glu23Lys showed no association with type 1 diabetes (P > 0.05). However, the PPARG2 Pro12Ala variant showed evidence of association (RR 1.15, 95% CI 1.041.28, P = 0.008). Additional studies need to be conducted to confirm this result.
Type 1 and 2 diabetes have been considered genetically and pathophysiologically distinct diseases, although clinically, it can sometimes be difficult to distinguish between them in individuals with deficient or absent endogenous insulin secretion, a feature common to both categories. Evidence does exist suggesting that there may be shared etiological features (13). Occasionally, individuals who develop diabetes late in life initially present in a similar manner to type 2 diabetes, but develop progressive ß-cell failure together with evidence of autoimmunity to islet cells, which is characteristic of type 1 diabetes. This so-called latent autoimmune diabetes in adults could suggest an overlap in the pathogenesis of type 1 and 2 diabetes in some cases. Furthermore, a recent study (4) has reported that early in the course of type 1 diabetes, individuals with evidence of islet autoimmunity may have normal fasting glucose but abnormal postprandial glucose tolerance. This pattern of defective postprandial secretion of insulin in response to nutrient intake is often observed in type 2 diabetes as well (4).
There has been some evidence of familial clustering of type 1 and 2 diabetes (5,6). However, the HLA region, the major locus in type 1 diabetes, has only infrequently been associated with type 2 diabetes (7). Moreover, both diseases have been associated with variation in the insulin gene but with predisposition determined by opposite alleles of the 5' variable number tandem repeat locus (8). Recently, genetic studies in type 2 diabetes have begun to reveal disease-associated polymorphisms that have established some level of general acceptance because they have been replicated by independent studies. Two polymorphisms that are well established as associated with type 2 diabetes are the single nucleotide polymorphisms (SNPs) Pro12Ala in the peroxisome proliferator-activated receptor gene isoform 2 (PPARG2), resulting from a C>G transversion, and Glu23Lys in the potassium inwardly rectifying channel gene (KCNJ11), resulting from an A>G transition (9). The reported effect sizes are modest (odds ratio [OR] 1.21.3) in meta-analyses (9,10). A large collaborative collection of type 1 diabetic families is now available for genetic analysis (11) with sufficient power to detect effects in the OR range of 1.21.3. Hence, in the present report we investigated the possibility that the two type 2 diabetes-associated SNPs were also associated with type 1 diabetes in an effort to begin to establish if overlaps exist in the two disease pathways. We have also tested the insulin receptor substrate 1 (IRS1) Gly972Arg polymorphism because it has been reported to be associated with type 1 diabetes (12), although it is not as well established in type 2 diabetes as the PPARG2 and KCNJ11 SNPs.
The PPARG gene encodes peroxisome proliferator-activated receptor (PPAR ), a member of the nuclear receptor superfamily that has regulatory functions in adipocyte differentiation and glucose homeostasis (13). PPAR is a target for a large family of antidiabetic drugs, the thiazolidinediones, that act as PPAR agonists and increase hepatic and peripheral insulin action in type 2 diabetes (14). In a meta-analysis of published studies through February 2003 (9), an OR of 1.27 was estimated for the Pro allele of isoform 2 (P value <2 x 10-8) in type 2 diabetes. This association is supported by functional data, as in vitro studies have shown that the Ala allele decreases the DNA-binding affinity of the PPAR 2, thus reducing its transcriptional activity (15).
The KCNJ11 Glu23Lys variant has also been consistently reported (10,16,17) to be associated with type 2 diabetes. KCNJ11 encodes for KIR6.2, which comprises one of the two subunits of the ß-cell ATP-sensitive potassium channel that regulates insulin secretion. A meta-analysis combining published case-control studies up to September 2002 (10) gave an OR of 1.23 (95% CI 1.121.36, P = 1.5 x 10-5) for the Lys allele, suggesting that this allele is associated with type 2 diabetes. In addition, functional data shows that the Lys variant may alter type 2 diabetes susceptibility by increasing the threshold ATP concentration necessary for insulin release, thus inducing spontaneous overactivity of pancreatic ß-cells (18). Increasing the metabolic activity of ß-cells might confer susceptibility to type 1 diabetes as well (19).
The insulin receptor substrate proteins (IRS1 and IRS2) are expressed in a variety of insulin responsive cells and tissues, mediating metabolic and growth-promoting actions of insulin and IGF-1. Observations from knockout mice suggest a role for these proteins in regulation of ß-cell function (20), and the human IRS1 Gly972Arg variant has been reported to be associated with type 2 diabetes (9). Meta-analysis, based on 3,408 case subjects and 5,419 control subjects from studies before January 2002 (21), resulted in an OR of 1.25 (95% CI 1.051.48). Of direct relevance to our study is a recent study (12) reporting an association of this variant with type 1 diabetes, with an OR of 2.5 (P = 0.0008) in a case-control study and a transmission/disequilibrium test (TDT) in simplex families giving a P value <0.02.
Therefore, we genotyped these three polymorphisms in 2,434 type 1 diabetic families of European descent. Parental genotype frequencies were found to be consistent with Hardy-Weinberg equilibrium. TDT and conditional logistic regression analyses were performed, and the results are summarized in Table 1. In this large dataset of type 1 diabetic families, we were unable to confirm the reported association of IRS1 (12), although we had >95% power to detect the reported effect (OR 2.5, P = 0.0008, minor allele frequency = 8%). Similarly, the KCNJ11 Glu23Lys variant was not associated with type 1 diabetes, as a nonsignificant deviation from 50:50 transmission from heterozygous parents was observed.
The PPARG2 Pro12Ala SNP, however, showed some evidence of association with the more common Pro allele conferring risk to type 1 diabetes (relative risk [RR] 1.15, 95% CI 1.041.28, P = 0.008), as is the case for type 2 diabetes. TDT results indicated a transmission to affected individuals of 54% (769 of 1,437 informative transmissions, P = 0.008). To confirm that this result was not due to genotyping error, we regenotyped the PPARG2 Pro12Ala SNP on the reverse strand and obtained 99.77% concordance. In agreement with the reports in type 2 diabetes, the minor allele (G) is protective in type 1 diabetes. Genotype RRs were calculated by conditional logistic regression analysis for the Pro12Ala SNP, giving values of 0.85 (0.760.95, P = 0.005) and 0.87 (0.611.24, P = 0.44) for the C/G and G/G genotypes, respectively, relative to the C/C genotype. Conversely, relative to the G/G genotype, the C/G and C/C genotypes have RRs of 0.98 (0.691.39) and 1.15 (0.811.64), respectively. The nonsignificant result for the G/G genotype (and the risks relative to the G/G genotype) is likely a result of its low frequency.
Our failure to replicate the Italian study (12), which reported an association between IRS1 Gly972Arg and type 1 diabetes, is perhaps not surprising given the modest sample size previously studied. Nevertheless, we genotyped this SNP with two technologies, as family studies of rare variants may be compromised because apparent undertransmission of alleles can be observed due to genotyping errors. A concordance rate of 99.74% was observed between genotypes generated by the two methods. It is unlikely that this common SNP could be genetically associated with type 1 diabetes in central Italy and not in other European countries. In these data we found no evidence of population heterogeneity ( 2 [4 df] = 1.93, P = 0.75, in five populations). Hence, our study highlights the importance of large datasets to investigate the multigenic basis of type 1 diabetes, type 2 diabetes, and other common multifactorial diseases.
If the PPARG2 Pro12Ala association is confirmed in other studies, then a molecular link would be established between type 1 and 2 diabetes involving a protective effect of the minor allele (Ala). Other studies have reported that thiazolidinediones possess anti-inflammatory properties and decrease diabetes incidence in nonobese diabetic (NOD) mice (22,23). Prevention of autoimmune diabetes in NOD mice by thiazolidinediones has been associated with suppression of intercellular adhesion molecule 1 (ICAM1) expression and alteration of Th1/Th2 cytokine balance (24). Interestingly, we have recently reported (25) an association of the Gly241Arg polymorphism of ICAM1 with type 1 diabetes. It is possible that PPAR agonists may be worth testing in prevention of immune rejection of transplanted islets.
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RESEARCH DESIGN AND METHODS
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All families were Caucasian of European descent and were composed of two parents and at least one affected child. The families comprised up to 458 Diabetes U.K. Warren 1 multiplex from the U.K. (26), 328 U.S. multiplex from the Human Biological Data Interchange (27), 80 Yorkshire simplex from the U.K., 250 Belfast multiplex/simplex (28) from the U.K., 159 Norwegian simplex, 233 Romanian simplex, and 926 Finnish multiplex/simplex (29). All DNA samples were collected with appropriate ethical approval and informed consent.
Genotyping.
SNPs were genotyped by the TaqMan 5' nuclease assay according to the manufacturers instructions (Applied Biosystems, Warrington, U.K.). TaqMan primers and probes were designed by Applied Biosystems. The PPARG2 Pro12Ala SNP was independently typed by the TaqMan 5' nuclease assay on both strands. IRS1 Gly972 Arg was also genotyped by restriction enzyme digest with XmaI, incorrectly reported as MvaI in Federici et al. (12). All genotyping data were double scored to minimize error.
Statistical analysis.
All statistical analyses were performed in Stata (http://www.stata.com) using the Genassoc package (http://www-gene.cimr.cam.ac.uk/clayton/software/stata). A modified test was used to evaluate Hardy-Weinberg equilibrium that allows for allelic frequencies to differ between known population groups. Allelic association was tested using the TDT. Pseudo-control subjects, generated by conditioning on parental genotype, allowed us to test genotypic association with conditional logistic regression (30). This also allowed us to test for population heterogeneity by adding appropriate interaction terms into the regression equation. Robust variance estimates were used for the calculation of P values and 95% CIs in order to correct for nonindependence of transmissions within families with more than one affected offspring. As a quality control measure, the transmission of PPARG2 Pro12Ala alleles to unaffected offspring was evaluated by TDT and found to be nonsignificant (data not shown), ruling out genotyping error as a possible explanation for the association observed with type 1 diabetes.
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ACKNOWLEDGMENTS
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We thank the Juvenile Diabetes Research Foundation and the Wellcome Trust for financial support.
We also thank the Human Biological Data Interchange and Diabetes U.K. for U.S. and U.K. multiplex families, respectively, the Norwegian Study Group for Childhood Diabetes for sample collection of Norwegian samples, Sarah Field and Tasneem Hassanali for DNA preparation, and David Clayton, Jason Cooper, and Chris Lowe for discussions.
Address correspondence and reprint requests to John A. Todd, JDRF/WT Diabetes and Inflammation Laboratory, Cambridge Institute for Medical Research, Wellcome Trust/MRC Building, Hills Rd., Cambridge CB2 2XY, U.K. E-mail: john.todd{at}cimr.cam.ac.uk
Received for publication October 3, 2003
and accepted in revised form October 31, 2003
Abbreviations:
ICAM1, intercellular adhesion molecule 1; IRS1, insulin receptor substrate 1; KCNJ11, potassium inwardly rectifying channel gene; PPAR , peroxisome proliferator-activated receptor ; PPARG2, peroxisome proliferator-activated receptor 2 gene; SNP, single nucleotide polymorphism; TDT, transmission/disequilibrium test
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REFERENCES
|
|---|
- Donath MY, Storling J, Maedler K, Mandrup-Poulsen T: Inflammatory mediators and islet beta-cell failure: a link between type 1 and type 2 diabetes.
J Mol Med81
:455
470,2003[Medline]
- Mathis D, Vence L, Benoist C: Beta-cell death during progression to diabetes.
Nature414
:792
798,2001[Medline]
- Wilkin TJ: The accelerator hypothesis: weight gain as the missing link between type I and type II diabetes.
Diabetologia44
:914
922,2001[Medline]
- Greenbaum CJ, Prigeon RL, DAlessio DA: Impaired ß-cell function, incretin effect, and glucagon suppression in patients with type 1 diabetes who have normal fasting glucose.
Diabetes51
:951
957,2002[Abstract/Free Full Text]
- Dahlquist G, Blom L, Tuvemo T, Nystrom L, Sandstrom A, Wall S: The Swedish childhood diabetes study: results from a nine year case register and a one year case-referent study indicating that type 1 (insulin-dependent) diabetes mellitus is associated with both type 2 (non-insulin-dependent) diabetes mellitus and autoimmune disorders.
Diabetologia32
:2
6,1989[Medline]
- Li H, Lindholm E, Almgren P, Gustafsson A, Forsblom C, Groop L, Tuomi T: Possible human leukocyte antigen-mediated genetic interaction between type 1 and type 2 diabetes.
J Clin Endocrinol Metab86
:574
582,2001[Abstract/Free Full Text]
- Tuomilehto-Wolf E, Tuomilehto J, Hitman GA, Nissinen A, Stengard J, Pekkanen J, Kivinen P, Kaarsalo E, Karvonen MJ: Genetic susceptibility to non-insulin dependent diabetes mellitus and glucose intolerance are located in HLA region.
BMJ307
:155
159,1993
- Bennett ST, Todd JA: Human type 1 diabetes and the insulin gene: principles of mapping polygenes.
Annu Rev Genet30
:343
370,1996[Medline]
- Florez JC, Hirschhorn J, Altshuler D: The inherited basis of diabetes mellitus: implications for the genetic analysis of complex traits.
Ann Rev Genomics Hum Genet4
:257
291,2003[Medline]
- Gloyn AL, Weedon MN, Owen KR, Turner MJ, Knight BA, Hitman G, Walker M, Levy JC, Sampson M, Halford S, McCarthy MI, Hattersley AT, Frayling TM: Large-scale association studies of variants in genes encoding the pancreatic ß-cell KATP channel subunits Kir6.2 (KCNJ11) and SUR1 (ABCC8) confirm that the KCNJ11 E23K variant is associated with type 2 diabetes.
Diabetes52
:568
572,2003[Abstract/Free Full Text]
- Dahlman I, Eaves IA, Kosoy R, Morrison VA, Heward J, Gough SC, Allahabadia A, Franklyn JA, Tuomilehto J, Tuomilehto-Wolf E, Cucca F, Guja C, Ionescu-Tirgoviste C, Stevens H, Carr P, Nutland S, McKinney P, Shield JP, Wang W, Cordell HJ, Walker N, Todd JA, Concannon P: Parameters for reliable results in genetic association studies in common disease.
Nat Genet30
:149
150,2002[Medline]
- Federici M, Petrone A, Porzio O, Bizzarri C, Lauro D, DAlfonso R, Patera I, Cappa M, Nistico L, Baroni M, Sesti G, di Mario U, Lauro R, Buzzetti R: The Gly972
Arg IRS-1 variant is associated with type 1 diabetes in continental Italy.
Diabetes52
:887
890,2003[Abstract/Free Full Text]
- Lee CH, Olson P, Evans RM: Minireview: lipid metabolism, metabolic diseases, and peroxisome proliferator-activated receptors.
Endocrinology144
:2201
2207,2003[Abstract/Free Full Text]
- Spiegelman BM: PPAR-
: adipogenic regulator and thiazolidinedione receptor.
Diabetes47
:507
514,1998[Abstract]
- Deeb SS, Fajas L, Nemoto M, Pihlajamaki J, Mykkanen L, Kuusisto J, Laakso M, Fujimoto W, Auwerx J: A Pro12Ala substitution in PPARgamma2 associated with decreased receptor activity, lower body mass index and improved insulin sensitivity.
Nat Genet20
:284
287,1998[Medline]
- Gloyn AL, Hashim Y, Ashcroft SJ, Ashfield R, Wiltshire S, Turner RC: Association studies of variants in promoter and coding regions of beta-cell ATP-sensitive K-channel genes SUR1 and Kir6.2 with type 2 diabetes mellitus (UKPDS 53).
Diabet Med18
:206
212,2001[Medline]
- Hani EH, Boutin P, Durand E, Inoue H, Permutt MA, Velho G, Froguel P: Missense mutations in the pancreatic islet beta cell inwardly rectifying K+ channel gene (KIR6.2/BIR): a meta-analysis suggests a role in the polygenic basis of type II diabetes mellitus in Caucasians.
Diabetologia41
:1511
1515,1998[Medline]
- Schwanstecher C, Meyer U, Schwanstecher M: K(IR)6.2 polymorphism predisposes to type 2 diabetes by inducing overactivity of pancreatic ß-cell ATP-sensitive K+ channels.
Diabetes51
:875
879,2002[Abstract/Free Full Text]
- Palmer JP: Beta cell rest and recovery: does it bring patients with latent autoimmune diabetes in adults to euglycemia?
Ann N Y Acad Sci958
:89
98,2002[Abstract/Free Full Text]
- Burks DJ, White MF: IRS proteins and ß-cell function.
Diabetes50 (Suppl. 1)
:S140
S145,2001
- Jellema A, Zeegers MP, Feskens EJ, Dagnelie PC, Mensink RP: Gly972Arg variant in the insulin receptor substrate-1 gene and association with type 2 diabetes: a meta-analysis of 27 studies.
Diabetologia46
:990
995,2003[Medline]
- Beales PE, Liddi R, Giorgini AE, Signore A, Procaccini E, Batchelor K, Pozzilli P: Troglitazone prevents insulin dependent diabetes in the non-obese diabetic mouse.
Eur J Pharmacol357
:221
225,1998[Medline]
- Beales PE, Pozzilli P: Thiazolidinediones for the prevention of diabetes in the non-obese diabetic (NOD) mouse: implications for human type 1 diabetes.
Diabete Metab Res Rev18
:114
117,2002
- Augstein P, Dunger A, Heinke P, Wachlin G, Berg S, Hehmke B, Salzsieder E: Prevention of autoimmune diabetes in NOD mice by troglitazone is associated with modulation of ICAM-1 expression on pancreatic islet cells and IFN-gamma expression in splenic T cells.
Biochem Biophys Res Commun304
:378
384,2003[Medline]
- Nezhentsev S, Guja C, McCormack R, Cooper J, Howson JMM, Nutland S, Rance H, Walker N, Undlien D, Ronningen KS, Tuomilehto-Wolf E, Tuomilehto J, Ionescu-Tirgoviste C, Gale EAM, Bingley PJ, Gillespie KM, Savage DA, Carson DJ, Patterson CC, Maxwell AP, Todd JA: The ARG241 allele of the intercellular adhesion molecule-1 is associated with a reduced risk of type 1 diabetes.
Lancet362
:1723
1724,2003[Medline]
- Bain SC, Todd JA, Barnett AH: The British Diabetic Association: Warren repository.
Autoimmunity7
:83
85,1990[Medline]
- Lernmark A, Ducat L, Eisenbarth G, Ott J, Permutt MA, Rubenstein P, Spielman R: Family cell lines available for research.
Am J Hum Genet47
:1028
1030,1990[Medline]
- Patterson CC, Carson DJ, Hadden DR, the Northern Ireland Diabetes Study Group: Epidemiology of childhood IDDM in Northern Ireland 19891994: low incidence in areas with highest population density and most household crowding.
Diabetologia39
:1063
1069,1996[Medline]
- Tuomilehto J, Lounamaa R, Tuomilehto-Wolf E, Reunanen A, Virtala E, Kaprio EA, Akerblom HK, the Childhood Diabetes in Finland (DiMe) Study Group: Epidemiology of childhood diabetes mellitus in Finland: background of a nationwide study of type 1 (insulin-dependent) diabetes mellitus.
Diabetologia35
:70
76,1992[Medline]
- Cordell HJ, Clayton DG: A unified stepwise regression procedure for evaluating the relative effects of polymorphisms within a gene using case/control or family data: application to HLA in type 1 diabetes.
Am J Hum Genet70
:124
141,2002[Medline]

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