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The role of genetics in fetal programming of adult cardiometabolic disease. J Dev Orig Health Dis 2021; 13:292-299. [PMID: 34176548 DOI: 10.1017/s2040174421000350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Disturbances affecting early development have broad repercussions on the individual's health during infancy and adulthood. Multiple observational studies throughout the years have shown that alterations of fetal growth are associated with increased cardiometabolic disease risks. However, the genetic component of this association only started to be investigated in the last 40 years, when single genes with distinct effects were investigated. Birth weight (BW), commonly reported as the outcome of developmental growth, has been estimated to be 20% to 60% heritable. Through Genome-Wide Association (GWA) meta-analyses, 190 different loci have been identified being associated with BW, and while many of these loci designate genes involved in glucose and lipid metabolism, with clear ties to fetal development, the role of others is not yet understood. In addition, due to its influence over the intrauterine environment, the maternal genotype also plays an important part in the determination of offspring BW, with the same loci having independent effects of different magnitude or even direction. There is still much to uncover regarding the genetic determinants of BW and the interactions between maternal, offspring, and even paternal genotype. To fully understand these, diverse and novel cohorts from multiple ancestries collecting extensive neonatal phenotype will be needed. This review compiles, chronologically, the main findings in the investigation of the genetics of BW.
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Zhang Y, Xiao X, Zhang Z, Ma X, Xu T, Li W, Feng K, Sun Q, Zhang Q. Role of high-risk variants in the development of impaired glucose metabolism was modified by birth weight in Han Chinese. Diabetes Metab Res Rev 2015; 31:790-5. [PMID: 26109524 DOI: 10.1002/dmrr.2670] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2014] [Revised: 05/21/2015] [Accepted: 06/09/2015] [Indexed: 12/25/2022]
Abstract
BACKGROUND The aim of this study was to investigate the role of common variants in the genes SLC30A8, KCNQ1, and TCF7L2 in the association between birth weight and increased risk of type 2 diabetes in Han Chinese. METHODS Seven variants (SLC30A8-rs13266634 and rs2466293; KCNQ1-rs2237895 and rs2074196; and TCF7L2-rs11196218, rs7903146, and rs290487) were genotyped in 1181 individuals born in Peking Union Medical College Hospital from 1921 to 1954 by Taqman allelic discrimination assay. All the subjects were stratified by birth weight into groups of ≥3000 g and <3000 g. Associations of genetic variants with birth weight and with risk of type 2 diabetes and impaired glucose tolerance (together as impaired glucose metabolism) were analysed. RESULTS After adjustment for sex, gestational weeks, parity, and maternal age, the G allele of KCNQ1-rs2074196 was associated with higher birth weight (p = 0.032). KCNQ1-rs2074196, rs2234895, and TCF7L2-rs290487 were associated with increased risk of impaired glucose metabolism. However, the associations were modified by size at birth. The associations above were only found in subjects with birth weights greater than (or equal to) 3000 g. In subjects with birth weights less than 3000 g, impaired glucose metabolism was associated with variants SLC30A8-rs2466293 and TCF7L2-rs11196218. CONCLUSIONS The role of common variants in susceptible genes in the development of impaired glucose metabolism was modified by birth weight in Han Chinese. This provides evidence that genetic variants influence birth weight and are involved in development of type 2 diabetes.
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Affiliation(s)
- Yun Zhang
- Key Laboratory of Endocrinology, Ministry of Health, Department of Endocrinology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, PR China
| | - Xinhua Xiao
- Key Laboratory of Endocrinology, Ministry of Health, Department of Endocrinology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, PR China
| | - Zhenxin Zhang
- Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, PR China
| | - Xuejun Ma
- Department of Core Facility, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, PR China
| | - Tao Xu
- Epidemiology and Statistics, School of Basic Medicine, Peking Union Medical College, PR China
| | - Wenhui Li
- Key Laboratory of Endocrinology, Ministry of Health, Department of Endocrinology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, PR China
| | - Kai Feng
- Key Laboratory of Endocrinology, Ministry of Health, Department of Endocrinology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, PR China
| | - Qi Sun
- Key Laboratory of Endocrinology, Ministry of Health, Department of Endocrinology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, PR China
| | - Qian Zhang
- Key Laboratory of Endocrinology, Ministry of Health, Department of Endocrinology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, PR China
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Morgan AR, Thompson JMD, Murphy R, Black PN, Lam WJ, Ferguson LR, Mitchell EA. Obesity and diabetes genes are associated with being born small for gestational age: results from the Auckland Birthweight Collaborative study. BMC MEDICAL GENETICS 2010; 11:125. [PMID: 20712903 PMCID: PMC2928774 DOI: 10.1186/1471-2350-11-125] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 03/31/2010] [Accepted: 08/16/2010] [Indexed: 01/01/2023]
Abstract
Background Individuals born small for gestational age (SGA) are at increased risk of rapid postnatal weight gain, later obesity and diseases in adulthood such as type 2 diabetes, hypertension and cardiovascular diseases. Environmental risk factors for SGA are well established and include smoking, low pregnancy weight, maternal short stature, maternal diet, ethnic origin of mother and hypertension. However, in a large proportion of SGA, no underlying cause is evident, and these individuals may have a larger genetic contribution. Methods In this study we tested the association between SGA and polymorphisms in genes that have previously been associated with obesity and/or diabetes. We undertook analysis of 54 single nucleotide polymorphisms (SNPs) in 546 samples from the Auckland Birthweight Collaborative (ABC) study. 227 children were born small for gestational age (SGA) and 319 were appropriate for gestational age (AGA). Results and Conclusion The results demonstrated that genetic variation in KCNJ11, BDNF, PFKP, PTER and SEC16B were associated with SGA and support the concept that genetic factors associated with obesity and/or type 2 diabetes are more prevalent in those born SGA compared to those born AGA. We have previously determined that environmental factors are associated with differences in birthweight in the ABC study and now we have demonstrated a significant genetic contribution, suggesting that the interaction between genetics and the environment are important.
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Affiliation(s)
- Angharad R Morgan
- Discipline of Nutrition, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand.
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Palmer ND, Langefeld CD, Bryer-Ash M, Rotter JI, Taylor KD, Bowden DW. Association of the Kir6.2 E23K variant with reduced acute insulin response in African-Americans. J Clin Endocrinol Metab 2008; 93:4979-83. [PMID: 18796522 PMCID: PMC2626454 DOI: 10.1210/jc.2008-0543] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT ATP-sensitive potassium channels are composed of pore-forming (Kir6.x) and regulatory sulfonylurea receptor (SURx) subunits and have been implicated in the maintenance of glucose homeostasis. Kir6.2 and SUR1 are expressed in a broad range of tissues, and no contemporary studies have addressed the physiological impact of variants in Hispanic-Americans and African-Americans carefully phenotyped for components of glucose homeostasis. OBJECTIVE The objective of this study was to evaluate two nonsynonymous variants in Kir6.2 (E23K) and SUR1 (A1369S) and determine their role in vivo. DESIGN AND SETTING The Insulin Resistance Atherosclerosis Family Study (IRAS-FS) is a community-based study of Hispanic-Americans (San Antonio, TX, and San Luis Valley, CO) and African-Americans (Los Angeles, CA). PARTICIPANTS A total of 1,040 Hispanic-Americans and 500 African-American individuals formed the basis of this study. MAIN OUTCOME MEASURE(S) The primary glucose homeostasis phenotypes of interest in this study were derived from the frequently sampled iv glucose tolerance test and included insulin sensitivity (S(I)), acute insulin response, and disposition index. RESULTS In African-Americans, both variants were associated with a significant reduction in insulin secretion in glucose-tolerant carriers of the minor alleles (additive P = 0.00053). S(I), a measure of insulin sensitivity, was not associated. In Hispanic-Americans, there was no association with measures of glucose homeostasis. CONCLUSIONS We conclude that variation marked by the Kir6.2 E23K and SUR1 A1369S mutations is associated with alterations in glucose-stimulated insulin secretion but not with other measures of glucose homeostasis in an African-American population.
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Affiliation(s)
- Nicholette D Palmer
- Department of Biochemistry, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157, USA
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Bennett AJ, Sovio U, Ruokonen A, Martikainen H, Pouta A, Hartikainen AL, Franks S, Elliott P, Järvelin MR, McCarthy MI. No evidence that established type 2 diabetes susceptibility variants in the PPARG and KCNJ11 genes have pleiotropic effects on early growth. Diabetologia 2008; 51:82-5. [PMID: 17994213 DOI: 10.1007/s00125-007-0863-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2007] [Accepted: 09/28/2007] [Indexed: 10/22/2022]
Abstract
AIMS/HYPOTHESIS The P12A variant in the PPARG gene and the E23K polymorphism in KCNJ11 are both known to influence individual predisposition to type 2 diabetes. If the effect of these variants on insulin secretion and action were to extend to an influence on early growth (which is largely mediated by insulin), it would offer an explanation for observed associations between low birthweight and subsequent diabetes. Since previous studies of the effects of these variants on early growth have been limited and conflicting, we examined these associations in a large, well-characterised birth cohort. METHODS The P12A and E23K variants were genotyped in (respectively) 5,652 and 5,632 individuals from the Northern Finland Birth Cohort of 1966 and we sought associations with early growth phenotypes. RESULTS Neither variant was associated with birthweight (P12A, p = 0.42; E23K, p = 0.44, additive models) or other measures of early growth. Although a previous report had suggested that the P12A effect on adult insulin sensitivity was restricted to small babies, we were unable to reproduce this finding (p = 0.40), nor did we confirm a previous report of an association with gestational age (p = 0.23). CONCLUSIONS/INTERPRETATION Despite a larger sample size than previous studies, we were unable to detect any effect of these variants on early growth. These findings do not support the notion that there are shared genetic determinants of low birthweight and adult diabetes.
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Affiliation(s)
- A J Bennett
- Oxford Centre for Diabetes, Endocrinology & Metabolism, University of Oxford, Oxford, OX3 7LJ, UK
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Yi Y, Dongmei L, Phares DA, Weiss EP, Brandauer J, Hagberg JM. Association betweenKCNJ11E23K genotype and cardiovascular and glucose metabolism phenotypes in older men and women. Exp Physiol 2007; 93:95-103. [PMID: 17720745 DOI: 10.1113/expphysiol.2007.038893] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Our objective was to investigate the relationship between the E23K genetic variant in the KCNJ11 gene, which encodes for the Kir6.2 subunit of the inward rectifier K+ channel family, and glucose and insulin metabolism and cardiovascular (CV) function in the sedentary state and their responses to exercise training. Two hundred and fourteen healthy sedentary men and women aged 50-75 years old and free of CV disease and type 2 diabetes underwent baseline testing (maximal oxygen consumption (Vo2max), body composition and glucose tolerance). One hundred and sixty-three of them repeated these tests after 24 weeks of exercise training while on a low-fat diet. At baseline, age, height, body fat, resting systolic blood pressure and all glucose and insulin metabolism markers did not differ among E23K genotype groups. In women at baseline, E23K genotype was associated with body weight, body mass index, Vo2max (ml kg(-1) min(-1), l min(-1)) and maximal minute ventilation. In men at baseline, E23K genotype was significantly associated with maximal heart rate, maximal respiratory exchange ratio and diastolic blood pressure at rest. Numerous glucose and insulin metabolism and CV function phenotypes changed significantly with exercise training in the total population. The E23K genotype did not significantly influence any of these training-induced changes. Thus, the common E23K genetic variant at the KCNJ11 gene locus was significantly associated with CV function in the untrained state, although the associations appear to differ between men and women. However, this variant has no significant effect on training-induced CV and glucose and insulin metabolism adaptations.
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Affiliation(s)
- Yang Yi
- Institute of Health Science, Wuhan Institute of Physical Education, Wuhan 430079, China
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Freathy RM, Weedon MN, Bennett A, Hypponen E, Relton CL, Knight B, Shields B, Parnell KS, Groves CJ, Ring SM, Pembrey ME, Ben-Shlomo Y, Strachan DP, Power C, Jarvelin MR, McCarthy MI, Davey Smith G, Hattersley AT, Frayling TM. Type 2 diabetes TCF7L2 risk genotypes alter birth weight: a study of 24,053 individuals. Am J Hum Genet 2007; 80:1150-61. [PMID: 17503332 PMCID: PMC1867102 DOI: 10.1086/518517] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2007] [Accepted: 03/22/2007] [Indexed: 12/20/2022] Open
Abstract
The role of genes in normal birth-weight variation is poorly understood, and it has been suggested that the genetic component of fetal growth is small. Type 2 diabetes genes may influence birth weight through maternal genotype, by increasing maternal glycemia in pregnancy, or through fetal genotype, by altering fetal insulin secretion. We aimed to assess the role of the recently described type 2 diabetes gene TCF7L2 in birth weight. We genotyped the polymorphism rs7903146 in 15,709 individuals whose birth weight was available from six studies and in 8,344 mothers from three studies. Each fetal copy of the predisposing allele was associated with an 18-g (95% confidence interval [CI] 7-29 g) increase in birth weight (P=.001) and each maternal copy with a 30-g (95% CI 15-45 g) increase in offspring birth weight (P=2.8x10-5). Stratification by fetal genotype suggested that the association was driven by maternal genotype (31-g [95% CI 9-48 g] increase per allele; corrected P=.003). Analysis of diabetes-related traits in 10,314 nondiabetic individuals suggested the most likely mechanism is that the risk allele reduces maternal insulin secretion (disposition index reduced by ~0.15 standard deviation; P=1x10-4), which results in increased maternal glycemia in pregnancy and hence increased offspring birth weight. We combined information with the other common variant known to alter fetal growth, the -30G-->A polymorphism of glucokinase (rs1799884). The 4% of offspring born to mothers carrying three or four risk alleles were 119 g (95% CI 62-172 g) heavier than were the 32% born to mothers with none (for overall trend, P=2x10-7), comparable to the impact of maternal smoking during pregnancy. In conclusion, we have identified the first type 2 diabetes-susceptibility allele to be reproducibly associated with birth weight. Common gene variants can substantially influence normal birth-weight variation.
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Affiliation(s)
- Rachel M Freathy
- Institute of Biomedical and Clinical Science, Peninsula Medical School, Exeter, UK
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Hattersley AT, Ashcroft FM. Activating mutations in Kir6.2 and neonatal diabetes: new clinical syndromes, new scientific insights, and new therapy. Diabetes 2005; 54:2503-13. [PMID: 16123337 DOI: 10.2337/diabetes.54.9.2503] [Citation(s) in RCA: 298] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Closure of ATP-sensitive K(+) channels (K(ATP) channels) in response to metabolically generated ATP or binding of sulfonylurea drugs stimulates insulin release from pancreatic beta-cells. Heterozygous gain-of-function mutations in the KCJN11 gene encoding the Kir6.2 subunit of this channel are found in approximately 47% of patients diagnosed with permanent diabetes at <6 months of age. There is a striking genotype-phenotype relationship with specific Kir6.2 mutations being associated with transient neonatal diabetes, permanent neonatal diabetes alone, and a novel syndrome characterized by developmental delay, epilepsy, and neonatal diabetes (DEND) syndrome. All mutations appear to cause neonatal diabetes by reducing K(ATP) channel ATP sensitivity and increasing the K(ATP) current, which inhibits beta-cell electrical activity and insulin secretion. The severity of the clinical symptoms is reflected in the ATP sensitivity of heterozygous channels in vitro with wild type > transient neonatal diabetes > permanent neonatal diabetes > DEND syndrome channels. Sulfonylureas still close mutated K(ATP) channels, and many patients can discontinue insulin injections and show improved glycemic control when treated with high-dose sulfonylurea tablets. In conclusion, the finding that Kir6.2 mutations can cause neonatal diabetes has enabled a new therapeutic approach and shed new light on the structure and function of the Kir6.2 subunit of the K(ATP) channel.
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Bennett A, Sovio U, Ruokonen A, Martikainen H, Pouta A, Taponen S, Hartikainen AL, Franks S, Peltonen L, Elliott P, Järvelin MR, McCarthy MI. No association between insulin gene variation and adult metabolic phenotypes in a large Finnish birth cohort. Diabetologia 2005; 48:886-91. [PMID: 15834700 DOI: 10.1007/s00125-005-1737-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2004] [Accepted: 12/30/2004] [Indexed: 10/25/2022]
Abstract
AIMS/HYPOTHESIS Although the variable number tandem repeat (VNTR) minisatellite 5' to the insulin gene is among the most studied polymorphisms in diabetes, the relationships between VNTR variation, diabetes-related traits and predisposition to type 2 diabetes remain unclear. Since inadequate sample size is likely to have been an obstacle to reliable inference, we examined the relationship between VNTR variation and a range of diabetes-related traits in a cohort of 5,753 Finnish adults. MATERIALS AND METHODS VNTR genotypes were derived, by typing at the -23HphI variant site, for 5,646 individuals from the Northern Finland Birth Cohort 1966. Associations were sought between these genotypes and a range of anthropometric (BMI, WHR), physiological (blood pressure) and biochemical (fasting glucose, insulin, lipids, indices of insulin sensitivity and beta cell function) measures obtained at clinical examination at 31 years. RESULTS We found no evidence that VNTR genotype was significantly associated with measures of insulin secretion, insulin sensitivity, glycaemia, adiposity or blood pressure. CONCLUSIONS/INTERPRETATION Despite evidence from several relatively small studies suggesting that INS-VNTR genotypes are associated with predisposition to type 2 diabetes, reduced beta cell function and measures of adiposity, the present study failed to detect any association with a range of diabetes-related traits. Taken with other recent studies in large population-based cohorts, these data suggest that previous studies have, at the very least, overestimated the influence of the INS-VNTR on type 2 diabetes-related traits. The effects of INS-VNTR variation on insulin transcription observed in vitro appear not to translate into detectable differences in basal insulin secretion in humans.
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Affiliation(s)
- A Bennett
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital Site, Old Road, Headington, Oxford OX3 7LJ, UK
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van Dam RM, Hoebee B, Seidell JC, Schaap MM, de Bruin TWA, Feskens EJM. Common variants in the ATP-sensitive K+ channel genes KCNJ11 (Kir6.2) and ABCC8 (SUR1) in relation to glucose intolerance: population-based studies and meta-analyses. Diabet Med 2005; 22:590-8. [PMID: 15842514 DOI: 10.1111/j.1464-5491.2005.01465.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
AIMS To evaluate the relation between common variants in the ATP-sensitive K+ channel genes and glucose intolerance. METHODS We conducted a meta-analysis of reported association studies in Caucasian populations for common variants in the ABCC8 (exons 16 and 18) and the KCNJ11 (E23K) gene and examined sources of heterogeneity in the results. The meta-analysis was based on 7768-10216 subjects (depending on the gene variant), and included two new population-based studies in the Netherlands with 725 cases and 742 controls. RESULTS For the KCNJ11 variant, the summary odds ratio (OR) for glucose intolerance was 1.12 (1.01-1.23, P=0.03) for the EK genotype and 1.44 (1.17-1.78, P=0.0007) for the KK genotype, as compared with the EE genotype. For the ABCC8 exon 16 variant, the OR was 1.06 (0.94-1.19, P=0.34) for ct and 0.93 (0.71-1.20, P=0.56) for tt, as compared with the cc genotype. For ABCC8 exon 18, the OR was 1.20 (0.97-1.49, P=0.10) for CT/TT, as compared with the CC genotype. Studies of the ABCC8 variants that were published first or had smaller sample sizes (for the exon 18 variant) showed stronger associations, which may indicate publication bias. For the ABCC8 exon 18 and the KCNJ11 variant, associations were stronger for studies of clinical diabetes than newly detected glucose intolerance. The population attributable risk for clinical Type 2 diabetes was 6.2% for the KCNJ11 KK genotype and 10.1% for the KCNJ11 EK and KK genotype combined. CONCLUSIONS The common KCNJ11 E23K gene variant, but not the ABCC8 exon 16 or exon 18 variant, was consistently associated with Type 2 diabetes.
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Affiliation(s)
- R M van Dam
- Centre of Nutrition and Health, National Institute for Public Health and the Environment, Bilthoven, the Netherlands.
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Li L, Shi Y, Wang X, Shi W, Jiang C. Single nucleotide polymorphisms in K(ATP) channels: muscular impact on type 2 diabetes. Diabetes 2005; 54:1592-7. [PMID: 15855351 DOI: 10.2337/diabetes.54.5.1592] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ATP-sensitive K+ channels (K(ATP) channels) play an important role in glucose homeostasis. A single nucleotide polymorphism (SNP) in the Kir6.2 subunit causes a point mutation of Glu23 to lysine and reduces the ATP sensitivity of pancreatic K(ATP) channels. The SNP found in 58% of Caucasians accounts for 15% of type 2 diabetes. Here we show evidence for dysregulations of muscular K(ATP) channels with the E23K variation. We were particularly interested in the channel modulation by intracellular protons, as pH changes widely and frequently in skeletal muscles. Surprisingly, we found that the defect of the E23K variant was more related to pH than ATP. A level of intracellular acidification seen during exercise not only activated the E23K channel more readily than the wild type, but also relieved the channel inhibition by ATP, leading to a vast increase in the channel open-state probability by approximately sevenfold at pH 6.8 over the wild-type channel at pH 7.4. Considering the reduction in sarcolemmal excitability, muscle fatigue, and impairment of muscular glucose uptake found previously by genetically disrupting K(ATP) channels, it is likely that the E23K variant in muscular K(ATP) channels affects systemic glucose homeostasis and poses an important risk factor for type 2 diabetes and obesity.
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Affiliation(s)
- Li Li
- Department of Biology, Georgia State University, 24 Peachtree Center Ave., Atlanta, Georgia 30302-4010, USA
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