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Rodríguez-Pardo C, Segura A, Zamorano-León JJ, Martínez-Santos C, Martínez D, Collado-Yurrita L, Giner M, García-García JM, Rodríguez-Pardo JM, López-Farre A. Decision tree learning to predict overweight/obesity based on body mass index and gene polymporphisms. Gene 2019; 699:88-93. [DOI: 10.1016/j.gene.2019.03.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 03/06/2019] [Accepted: 03/07/2019] [Indexed: 12/26/2022]
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2
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Apalasamy YD, Mohamed Z. Obesity and genomics: role of technology in unraveling the complex genetic architecture of obesity. Hum Genet 2015; 134:361-74. [PMID: 25687726 DOI: 10.1007/s00439-015-1533-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 02/02/2015] [Indexed: 01/15/2023]
Abstract
Obesity is a complex and multifactorial disease that occurs as a result of the interaction between "obesogenic" environmental factors and genetic components. Although the genetic component of obesity is clear from the heritability studies, the genetic basis remains largely elusive. Successes have been achieved in identifying the causal genes for monogenic obesity using animal models and linkage studies, but these approaches are not fruitful for polygenic obesity. The developments of genome-wide association approach have brought breakthrough discovery of genetic variants for polygenic obesity where tens of new susceptibility loci were identified. However, the common SNPs only accounted for a proportion of heritability. The arrival of NGS technologies and completion of 1000 Genomes Project have brought other new methods to dissect the genetic architecture of obesity, for example, the use of exome genotyping arrays and deep sequencing of candidate loci identified from GWAS to study rare variants. In this review, we summarize and discuss the developments of these genetic approaches in human obesity.
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Affiliation(s)
- Yamunah Devi Apalasamy
- Department of Pharmacology, Pharmacogenomics Laboratory, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia,
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3
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Kaulfers AM, Deka R, Dolan L, Martin LJ. Association of INSIG2 polymorphism with overweight and LDL in children. PLoS One 2015; 10:e0116340. [PMID: 25607990 PMCID: PMC4301876 DOI: 10.1371/journal.pone.0116340] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 12/08/2014] [Indexed: 11/19/2022] Open
Abstract
Background Dyslipidemia and overweight are common issues in children. Identifying genetic markers of risk could lead to targeted interventions. A polymorphism of SNP rs7566605 near insulin-induced gene 2 (INSIG2) has been identified as a strong candidate gene for obesity, through its feedback control of lipid synthesis. Objective To identify polymorphisms in INSIG2 which are associated with overweight (BMI ≥ 85% for age) and dyslipidemia in children. Hypothesis: The C allele of rs7566605 would be significantly associated with BMI and LDL. Design/Methods We genotyped 15 SNPs in/near INSIG2 in 1,058 healthy children (53% non-Hispanic white (NHW), 37% overweight) participating in a school based study. Genotype was compared with BMI and lipid markers, adjusting for age, gender, and puberty. Results We found a significant association between the SNP rs12464355 and LDL in NHW children, p < 0.001. The G allele is protective (lower LDL). A different SNP was associated with overweight in NHW: rs17047757. SNP rs7566605 was not associated with overweight or lipid levels. Conclusions We identified novel genetic associations between INSIG2 and both overweight and LDL in NHW children. Polymorphisms in INSIG2 may be important in the development of obesity through its effects on lipid regulation.
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Affiliation(s)
- Anne-Marie Kaulfers
- Division of Pediatric Endocrinology, University of South Alabama, Mobile, Alabama, United States of America
- * E-mail:
| | - Ranjan Deka
- Department of Environmental Health, University of Cincinnati School of Medicine, Cincinnati, Ohio, United States of America
| | - Lawrence Dolan
- Division of Endocrinology, Cincinnati Children’s Hospital Medical Center and University of Cincinnati School of Medicine, Cincinnati, Ohio, United States of America
| | - Lisa J. Martin
- Divisions of Biostatistics and Epidemiology, Division of Human Genetics, Cincinnati Children’s Hospital Medical Center and University of Cincinnati School of Medicine, Cincinnati, Ohio, United States of America
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4
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Popadic Gacesa JZ, Secher NH, Momcilovic M, Grujic NG. Association between intramuscular fat in the arm following arm training andINSIG2. Scand J Med Sci Sports 2013; 24:907-12. [DOI: 10.1111/sms.12102] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/01/2013] [Indexed: 12/25/2022]
Affiliation(s)
- J. Z. Popadic Gacesa
- Department of Physiology; Medical School; University of Novi Sad; Novi Sad Serbia
| | - N. H. Secher
- The Copenhagen Muscle Research Center; Department of Anesthesiology; Rigshospitalet; University of Copenhagen; Copenhagen Denmark
| | - M. Momcilovic
- Department of Biochemistry; Medical School; University of Novi Sad; Novi Sad Serbia
| | - N. G. Grujic
- Department of Physiology; Medical School; University of Novi Sad; Novi Sad Serbia
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5
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Baylin A, Deka R, Tuitele J, Viali S, Weeks DE, McGarvey ST. INSIG2 variants, dietary patterns and metabolic risk in Samoa. Eur J Clin Nutr 2013; 67:101-7. [PMID: 22968099 PMCID: PMC3634362 DOI: 10.1038/ejcn.2012.124] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Revised: 08/16/2012] [Accepted: 08/18/2012] [Indexed: 12/11/2022]
Abstract
BACKGROUND/OBJECTIVES Association of insulin-induced gene 2 (INSIG2) variants with obesity has been confirmed in several but not all follow-up studies. Differences in environmental factors across populations may mask some genetic associations and therefore gene-environment interactions should be explored. We hypothesized that the association between dietary patterns and components of the metabolic syndrome could be modified by INSIG2 variants. SUBJECTS/METHODS We conducted a longitudinal study of adiposity and cardiovascular disease risk among 427 and 290 adults from Samoa and American Samoa (1990-1995). Principal component analysis on food items from a validated food frequency questionnaire was used to identify neotraditional and modern dietary patterns. We explored gene-dietary pattern interactions with the INSIG2 variants rs9308762 and rs7566605. RESULTS Results for American Samoans were mostly nonsignificant. In Samoa, the neotraditional dietary pattern was associated with lower triglycerides, body mass index (BMI), waist circumference, systolic and diastolic blood pressure and fasting glucose (all P-for-trend<0.05). The modern pattern was significantly associated with higher triglycerides, BMI, waist circumference and lower high-density lipoprotein-cholesterol (all P-for-trend<0.05). A significant interaction for triglycerides was found between the modern pattern and the rs9308762 polymorphism (P=0.04). Those from Samoa consuming the modern pattern have higher triglycerides if they are homozygous for the rs9308762 C allele. CONCLUSIONS The common INSIG2 variant rs9308762 was associated with poorer metabolic control and a greater sensitivity of trigylcerides to a modern dietary pattern. Environmental factors need to be taken into account when assessing genetic associations across and within populations.
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Affiliation(s)
- A Baylin
- Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, MI, USA.
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6
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Campa D, Hüsing A, McKay JD, Sinilnikova O, Vogel U, Tjønneland A, Overvad K, Stegger J, Clavel-Chapelon F, Chabbert-Buffet N, Fagherazzi G, Trichopoulou A, Zylis D, Oustoglou E, Rohrmann S, Teucher B, Fisher E, Boeing H, Masala G, Krogh V, Sacerdote C, Panico S, Tumino R, Onland-Moret NC, van Gils CH, Bueno-de-Mesquita HB, Lund E, Chirlaque MD, Sala N, Quirós JR, Ardanaz E, Amiano P, Molina-Montes E, Hallmans G, Lenner P, Travis RC, Key TJ, Wareham N, Khaw KT, Rinaldi S, Slimani N, Chajes V, Siddiq A, Riboli E, Kaaks R, Canzian F. The INSIG2 rs7566605 polymorphism is not associated with body mass index and breast cancer risk. BMC Cancer 2010; 10:563. [PMID: 20955599 PMCID: PMC2965729 DOI: 10.1186/1471-2407-10-563] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2010] [Accepted: 10/18/2010] [Indexed: 01/12/2023] Open
Abstract
Background The single nucleotide polymorphism rs7566605, located in the promoter of the INSIG2 gene, has been the subject of a strong scientific effort aimed to elucidate its possible association with body mass index (BMI). The first report showing that rs7566605 could be associated with body fatness was a genome-wide association study (GWAS) which used BMI as the primary phenotype. Many follow-up studies sought to validate the association of rs7566605 with various markers of obesity, with several publications reporting inconsistent findings. BMI is considered to be one of the measures of choice to evaluate body fatness and there is evidence that body fatness is related with an increased risk of breast cancer (BC). Methods we tested in a large-scale association study (3,973 women, including 1,269 invasive BC cases and 2,194 controls), nested within the EPIC cohort, the involvement of rs7566605 as predictor of BMI and BC risk. Results and Conclusions In this study we were not able to find any statistically significant association between this SNP and BMI, nor did we find any significant association between the SNP and an increased risk of breast cancer overall and by subgroups of age, or menopausal status.
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Affiliation(s)
- Daniele Campa
- German Cancer Research Center (DKFZ), Heidelberg, Germany
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7
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Do R, Bailey SD, Paré G, Montpetit A, Desbiens K, Hudson TJ, Yusuf S, Bouchard C, Gaudet D, Pérusse L, Anand S, Vohl MC, Pastinen T, Engert JC. Fine Mapping of the Insulin-Induced Gene 2 Identifies a Variant Associated With LDL Cholesterol and Total Apolipoprotein B Levels. ACTA ACUST UNITED AC 2010; 3:454-61. [DOI: 10.1161/circgenetics.109.917039] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Background—
In a whole-genome scan, a single nucleotide polymorphism (SNP) (rs7566605) upstream of the insulin-induced gene 2 (
INSIG2
) was shown to influence body mass index and obesity in the Framingham Heart Study, with replication of these results in an additional 4 of 5 studies. However, other studies could not replicate the association. Because
INSIG2
plays an important role in cholesterol biosynthesis, we hypothesized that human
INSIG2
variants might play a role in the regulation of plasma lipid and lipoprotein levels.
Methods and Results—
We selected tagging SNPs spanning >100 kb of
INSIG2
locus and sequenced 18 434 base pairs to discover novel SNPs. Thirty-two SNPs were genotyped in 645 individuals from the Quebec Family Study. Two SNPs (rs10490626 and rs12464355) were associated with plasma low-density lipoprotein cholesterol (LDL-C) (
P
<0.0015) and total apolipoprotein B (apoB) levels (
P
<0.014), whereas no association was found between any SNP and body mass index. We replicated the finding of rs10490626 for both LDL-C and total apoB in additional study samples, including 758 individuals from Saguenay–Lac St. Jean, Quebec (
P
=0.040 for LDL-C,
P
=0.044 for apoB), 3247 Europeans (
P
=0.028 for LDL-C,
P
=0.030 for apoB), and 1695 South Asians (
P
=0.0036 for LDL-C,
P
=0.034 for apoB) from the INTERHEART study (for LDL-C, the combined 2-sided
P
=6.2×10
−5
and for total apoB,
P
=0.0011). Furthermore, we identified a variant in the human sorbin and SH
3
-domain–containing-1 gene that was associated with
INSIG2
mRNA levels, and this SNP was shown to act in combination with rs10490626 to affect LDL-C (
P
=0.022) in the Quebec Family Study and in INTERHEART South Asians (
P
=0.019) and Europeans (
P
=0.052).
Conclusion—
These results suggest that
INSIG2
genetic variants may have a more direct role in lipid and lipoprotein metabolism than in obesity.
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Affiliation(s)
- Ron Do
- From the Department of Human Genetics (R.D., S.D.B, G.P., T.P., J.C.E.), McGill University, McGill University and Genome Québec Innovation Centre (G.P., A.M., T.J.H., T.P.); and Research Institute of McGill University Health Centre (K.D., J.C.E.), Montreal, Canada; Pennington Biomedical Research Center (C.B.), Baton Rouge, La; Department of Medicine (D.G.), University of Montreal, and ECOGENE-21 Clinical Research Center, Chicoutimi Hospital; Department of Social and Preventive Medicine (L.P.),
| | - Swneke D. Bailey
- From the Department of Human Genetics (R.D., S.D.B, G.P., T.P., J.C.E.), McGill University, McGill University and Genome Québec Innovation Centre (G.P., A.M., T.J.H., T.P.); and Research Institute of McGill University Health Centre (K.D., J.C.E.), Montreal, Canada; Pennington Biomedical Research Center (C.B.), Baton Rouge, La; Department of Medicine (D.G.), University of Montreal, and ECOGENE-21 Clinical Research Center, Chicoutimi Hospital; Department of Social and Preventive Medicine (L.P.),
| | - Guillaume Paré
- From the Department of Human Genetics (R.D., S.D.B, G.P., T.P., J.C.E.), McGill University, McGill University and Genome Québec Innovation Centre (G.P., A.M., T.J.H., T.P.); and Research Institute of McGill University Health Centre (K.D., J.C.E.), Montreal, Canada; Pennington Biomedical Research Center (C.B.), Baton Rouge, La; Department of Medicine (D.G.), University of Montreal, and ECOGENE-21 Clinical Research Center, Chicoutimi Hospital; Department of Social and Preventive Medicine (L.P.),
| | - Alexandre Montpetit
- From the Department of Human Genetics (R.D., S.D.B, G.P., T.P., J.C.E.), McGill University, McGill University and Genome Québec Innovation Centre (G.P., A.M., T.J.H., T.P.); and Research Institute of McGill University Health Centre (K.D., J.C.E.), Montreal, Canada; Pennington Biomedical Research Center (C.B.), Baton Rouge, La; Department of Medicine (D.G.), University of Montreal, and ECOGENE-21 Clinical Research Center, Chicoutimi Hospital; Department of Social and Preventive Medicine (L.P.),
| | - Katia Desbiens
- From the Department of Human Genetics (R.D., S.D.B, G.P., T.P., J.C.E.), McGill University, McGill University and Genome Québec Innovation Centre (G.P., A.M., T.J.H., T.P.); and Research Institute of McGill University Health Centre (K.D., J.C.E.), Montreal, Canada; Pennington Biomedical Research Center (C.B.), Baton Rouge, La; Department of Medicine (D.G.), University of Montreal, and ECOGENE-21 Clinical Research Center, Chicoutimi Hospital; Department of Social and Preventive Medicine (L.P.),
| | - Thomas J. Hudson
- From the Department of Human Genetics (R.D., S.D.B, G.P., T.P., J.C.E.), McGill University, McGill University and Genome Québec Innovation Centre (G.P., A.M., T.J.H., T.P.); and Research Institute of McGill University Health Centre (K.D., J.C.E.), Montreal, Canada; Pennington Biomedical Research Center (C.B.), Baton Rouge, La; Department of Medicine (D.G.), University of Montreal, and ECOGENE-21 Clinical Research Center, Chicoutimi Hospital; Department of Social and Preventive Medicine (L.P.),
| | - Salim Yusuf
- From the Department of Human Genetics (R.D., S.D.B, G.P., T.P., J.C.E.), McGill University, McGill University and Genome Québec Innovation Centre (G.P., A.M., T.J.H., T.P.); and Research Institute of McGill University Health Centre (K.D., J.C.E.), Montreal, Canada; Pennington Biomedical Research Center (C.B.), Baton Rouge, La; Department of Medicine (D.G.), University of Montreal, and ECOGENE-21 Clinical Research Center, Chicoutimi Hospital; Department of Social and Preventive Medicine (L.P.),
| | - Claude Bouchard
- From the Department of Human Genetics (R.D., S.D.B, G.P., T.P., J.C.E.), McGill University, McGill University and Genome Québec Innovation Centre (G.P., A.M., T.J.H., T.P.); and Research Institute of McGill University Health Centre (K.D., J.C.E.), Montreal, Canada; Pennington Biomedical Research Center (C.B.), Baton Rouge, La; Department of Medicine (D.G.), University of Montreal, and ECOGENE-21 Clinical Research Center, Chicoutimi Hospital; Department of Social and Preventive Medicine (L.P.),
| | - Daniel Gaudet
- From the Department of Human Genetics (R.D., S.D.B, G.P., T.P., J.C.E.), McGill University, McGill University and Genome Québec Innovation Centre (G.P., A.M., T.J.H., T.P.); and Research Institute of McGill University Health Centre (K.D., J.C.E.), Montreal, Canada; Pennington Biomedical Research Center (C.B.), Baton Rouge, La; Department of Medicine (D.G.), University of Montreal, and ECOGENE-21 Clinical Research Center, Chicoutimi Hospital; Department of Social and Preventive Medicine (L.P.),
| | - Louis Pérusse
- From the Department of Human Genetics (R.D., S.D.B, G.P., T.P., J.C.E.), McGill University, McGill University and Genome Québec Innovation Centre (G.P., A.M., T.J.H., T.P.); and Research Institute of McGill University Health Centre (K.D., J.C.E.), Montreal, Canada; Pennington Biomedical Research Center (C.B.), Baton Rouge, La; Department of Medicine (D.G.), University of Montreal, and ECOGENE-21 Clinical Research Center, Chicoutimi Hospital; Department of Social and Preventive Medicine (L.P.),
| | - Sonia Anand
- From the Department of Human Genetics (R.D., S.D.B, G.P., T.P., J.C.E.), McGill University, McGill University and Genome Québec Innovation Centre (G.P., A.M., T.J.H., T.P.); and Research Institute of McGill University Health Centre (K.D., J.C.E.), Montreal, Canada; Pennington Biomedical Research Center (C.B.), Baton Rouge, La; Department of Medicine (D.G.), University of Montreal, and ECOGENE-21 Clinical Research Center, Chicoutimi Hospital; Department of Social and Preventive Medicine (L.P.),
| | - Marie-Claude Vohl
- From the Department of Human Genetics (R.D., S.D.B, G.P., T.P., J.C.E.), McGill University, McGill University and Genome Québec Innovation Centre (G.P., A.M., T.J.H., T.P.); and Research Institute of McGill University Health Centre (K.D., J.C.E.), Montreal, Canada; Pennington Biomedical Research Center (C.B.), Baton Rouge, La; Department of Medicine (D.G.), University of Montreal, and ECOGENE-21 Clinical Research Center, Chicoutimi Hospital; Department of Social and Preventive Medicine (L.P.),
| | - Tomi Pastinen
- From the Department of Human Genetics (R.D., S.D.B, G.P., T.P., J.C.E.), McGill University, McGill University and Genome Québec Innovation Centre (G.P., A.M., T.J.H., T.P.); and Research Institute of McGill University Health Centre (K.D., J.C.E.), Montreal, Canada; Pennington Biomedical Research Center (C.B.), Baton Rouge, La; Department of Medicine (D.G.), University of Montreal, and ECOGENE-21 Clinical Research Center, Chicoutimi Hospital; Department of Social and Preventive Medicine (L.P.),
| | - James C. Engert
- From the Department of Human Genetics (R.D., S.D.B, G.P., T.P., J.C.E.), McGill University, McGill University and Genome Québec Innovation Centre (G.P., A.M., T.J.H., T.P.); and Research Institute of McGill University Health Centre (K.D., J.C.E.), Montreal, Canada; Pennington Biomedical Research Center (C.B.), Baton Rouge, La; Department of Medicine (D.G.), University of Montreal, and ECOGENE-21 Clinical Research Center, Chicoutimi Hospital; Department of Social and Preventive Medicine (L.P.),
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8
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Zavattari P, Loche A, Civolani P, Pilia S, Moi L, Casini MR, Minerba L, Loche S. An INSIG2 Polymorphism Affects Glucose Homeostasis in Sardinian Obese Children and Adolescents. Ann Hum Genet 2010; 74:381-6. [DOI: 10.1111/j.1469-1809.2010.00590.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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9
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Deka R, Xu L, Pal P, Toelupe PT, Laumoli TS, Xi H, Zhang G, Weeks DE, McGarvey ST. A tagging SNP in INSIG2 is associated with obesity-related phenotypes among Samoans. BMC MEDICAL GENETICS 2009; 10:143. [PMID: 20028541 PMCID: PMC2804583 DOI: 10.1186/1471-2350-10-143] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2009] [Accepted: 12/22/2009] [Indexed: 11/30/2022]
Abstract
Background A genome wide association study found significant association of a sequence variant, rs7566605, in the insulin-induced gene 2 (INSIG2) with obesity. However, the association remained inconclusive in follow-up studies. We tested for association of four tagging SNPs (tagSNPs) including this variant with body mass index (BMI) and abdominal circumference (ABDCIR) in the Samoans of the Western Pacific, a population with high levels of obesity. Methods We studied 907 adult Samoan participants from a longitudinal study of adiposity and cardiovascular disease risk in two polities, American Samoa and Samoa. Four tagSNPs were identified from the Chinese HapMap database based on pairwise r2 of ≥0.8 and minor allele frequency of ≥0.05. Genotyping was performed using the TaqMan assay. Tests of association with BMI and ABDCIR were performed under the additive model. Results We did not find association of rs7566605 with either BMI or ABDCIR in any group of the Samoans. However, the most distally located tagSNPs in Intron 3 of the gene, rs9308762, showed significant association with both BMI (p-value 0.024) and ABDCIR (p-value 0.009) in the combined sample and with BMI (p-value 0.038) in the sample from Samoa. Conclusion Although rs7566605 was not significantly associated with obesity in our study population, we can not rule out the involvement of INSIG2 in obesity related traits as we found significant association of another tagSNP in INSIG2 with both BMI and ABDCIR. This study suggests the importance of comprehensive assessment of sequence variants within a gene in association studies.
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Affiliation(s)
- Ranjan Deka
- Center for Genome Information, Department of Environmental Health, University of Cincinnati College of Medicine, 3223 Eden Avenue, Cincinnati, OH 45267, USA.
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10
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Cha S, Koo I, Choi SM, Park BL, Kim KS, Kim JR, Shin HD, Kim JY. Association analyses of the INSIG2 polymorphism in the obesity and cholesterol levels of Korean populations. BMC MEDICAL GENETICS 2009; 10:96. [PMID: 19772594 PMCID: PMC2759923 DOI: 10.1186/1471-2350-10-96] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/13/2009] [Accepted: 09/22/2009] [Indexed: 12/14/2022]
Abstract
Background While INSIG2 has been reported to be associated with BMI in many populations, conflicting results have prevented consensus over its role. In analyses of mice and cell cultures the gene has been found to be involved in the regulation of cholesterol synthesis; however, no relationship has been found with cholesterol metabolism in human epidemiological research. Therefore, this study attempts to assess the effect of rs7566605 near INSIG2 on both obesity- and cholesterol-related traits in Koreans. Methods The rs7566605 polymorphism was genotyped with 2,364 Koreans, and associations with obesity- and cholesterol-related traits were analyzed statistically via an ANOVA or T-test. Results Replication of an association with BMI, WHR, fat mass, fat percent, and abdominal fat area failed, and the C allele of rs7566605 was not associated significantly with total cholesterol, HDL cholesterol, or triglyceride. However, it was found in a meta-analysis of a dominant model that the C allele of rs7566605 appeared to affect the level of the total cholesterol, especially in female subjects. Conclusion We failed to show associations of rs7566605 with cholesterol- and obesity-related phenotypes, although we newly suggest the possible involvement of INSIG2 with the plasma level of the total cholesterol in women.
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Affiliation(s)
- Seongwon Cha
- Division of Constitutional Medicine Research, Korea Institute of Oriental Medicine, 483 Exporo, Daejeon, Republic of Korea.
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11
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Talbert ME, Langefeld CD, Ziegler JT, Haffner SM, Norris JM, Bowden DW. INSIG2 SNPs associated with obesity and glucose homeostasis traits in Hispanics: the IRAS Family Study. Obesity (Silver Spring) 2009; 17:1554-62. [PMID: 19360016 PMCID: PMC2916685 DOI: 10.1038/oby.2009.94] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The genome-wide association study by Herbert et al. identified the INSIG2 single-nucleotide polymorphism (SNP) rs7566605 as contributing to increased BMI in ethnically distinct cohorts. The present study sought to further clarify the matter, by testing whether SNPs of INSIG2 influenced quantitative adiposity or glucose homeostasis traits in Hispanics of the Insulin Resistance Atherosclerosis Family Study (IRASFS). Using a tagging SNP approach, rs7566605 and 31 additional SNPs were genotyped in 1,425 IRASFS Hispanics. SNPs were tested for association with six adiposity measures: BMI, waist circumference (WAIST), waist-to-hip ratio (WHR), subcutaneous adipose tissue (SAT), visceral adipose tissue (VAT), and VAT to SAT ratio (VSR). SNPs were also tested for association with fasting glucose (GFAST), fasting insulin (FINS), and three measures obtained from the frequently sampled intravenous glucose tolerance test: insulin sensitivity (S(I)), acute insulin response (AIR), and disposition index (DI). Most prominent association was observed with direct computed tomography (CT)-measured adiposity phenotypes, including VAT, SAT, and VSR (P values range from 0.007 to 0.044 for rs17586756, rs17047718, rs17047731, rs9308762, rs12623648, and rs11673900). Multiple SNP associations were observed with all glucose homeostasis traits (P values range from 0.001 to 0.031 for rs17047718, rs17047731, rs2161829, rs10490625, rs889904, and rs12623648). Using BMI as a covariate in evaluation of glucose homeostasis traits slightly reduced their association. However, association with adiposity and glucose homeostasis phenotypes is not significant following multiple comparisons adjustment. Trending association after multiple comparisons adjustment remains suggestive of a role for genetic variation of INSIG2 in obesity, but these results require validation.
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Affiliation(s)
- Matthew E Talbert
- Program in Molecular Medicine and Translational Sciences, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA
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12
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Peeters A, Beckers S, Verrijken A, Mertens I, Van Gaal L, Van Hul W. Possible role for ENPP1 polymorphism in obesity but not for INSIG2 and PLIN variants. Endocrine 2009; 36:103-9. [PMID: 19399648 DOI: 10.1007/s12020-009-9194-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2009] [Revised: 03/13/2009] [Accepted: 04/01/2009] [Indexed: 10/20/2022]
Abstract
Previous studies have suggested that ENPP1, INSIG2, and PLIN may be linked with a higher risk for obesity or with increased phenotypic measures of obesity. We selected polymorphisms in these candidate genes based on their prior associations with obesity risk or obesity parameters. K121Q (rs1044498) in ENPP1, rs7566605 in INSIG2, and rs894160 in PLIN were genotyped by Taqman assays in a Belgian sample of 1,078 obese subjects (body mass index (BMI) > 30 kg/m(2)) and 323 lean controls (18.5 < BMI < 25 kg/m(2)). BMI, waist circumference, and waist-to-hip ratio (WHR) were assessed by standard methods while a computerized tomography-scan was used to measure visceral (VFA), subcutaneous (SFA), and total (TFA) abdominal fat areas. Presence of the rare allele was not significantly different between cases and controls for the three variants that were tested, while only WHR was associated with ENPP1 in obese subjects. Our data thus indicate that K121Q, rs7566605, and rs894160 are not major contributing factors for obesity.
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Affiliation(s)
- Armand Peeters
- Department of Biomedical Sciences, University of Antwerp, Universiteitsplein 1, Wilrijk, 2610, Antwerp, Belgium.
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Vimaleswaran KS, Franks PW, Brage S, Sardinha LB, Andersen LB, Wareham NJ, Ekelund U, Loos RJF. Absence of association between the INSIG2 gene polymorphism (rs7566605) and obesity in the European Youth Heart Study (EYHS). Obesity (Silver Spring) 2009; 17:1453-7. [PMID: 19197262 DOI: 10.1038/oby.2008.650] [Citation(s) in RCA: 13] [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: 11/09/2022]
Abstract
The first genome-wide association study for BMI identified a polymorphism, rs7566605, 10 kb upstream of the insulin-induced gene 2 (INSIG2) transcription start site, as the most significantly associated variant in children and adults. Subsequent studies, however, showed inconsistent association of this polymorphism with obesity traits. This polymorphism has been hypothesized to alter INSIG2 expression leading to inhibition of fatty acid and cholesterol synthesis. Hence, we investigated the association of the INSIG2 rs7566605 polymorphism with obesity- and lipid-related traits in Danish and Estonian children (930 boys and 1,073 girls) from the European Youth Heart Study (EYHS), a school-based, cross-sectional study of pre- and early pubertal children. The association between the polymorphism and obesity traits was tested using additive and recessive models adjusted for age, age-group, gender, maturity and country. Interactions were tested by including the interaction terms in the model. Despite having sufficient power (98%) to detect the previously reported effect size for association with BMI, we did not find significant effects of rs7566605 on BMI (additive, P = 0.68; recessive, P = 0.24). Accordingly, the polymorphism was not associated with overweight (P = 0.87) or obesity (P = 0.34). We also did not find association with waist circumference (WC), sum of four skinfolds, or with total cholesterol, triglycerides, low-density lipoprotein, or high-density lipoprotein. There were no gender-specific (P = 0.55), age-group-specific (P = 0.63) or country-specific (P = 0.56) effects. There was also no evidence of interaction between genotype and physical activity (P = 0.95). Despite an adequately powered study, our findings suggest that rs7566605 is not associated with obesity-related traits and lipids in the EYHS.
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Wiedmann S, Neureuther K, Stark K, Reinhard W, Kallmünzer B, Baessler A, Fischer M, Linsel-Nitschke P, Erdmann J, Schunkert H, Hengstenberg C. Lack of association between a common polymorphism near the INSIG2 gene and BMI, myocardial infarction, and cardiovascular risk factors. Obesity (Silver Spring) 2009; 17:1390-5. [PMID: 19197259 DOI: 10.1038/oby.2008.669] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Epidemiological studies revealed an increasing prevalence of and a steep increase in obesity, a risk factor for cardiovascular disease. Because significant influence of a polymorphism, rs7566605, near the INSIG2 gene on BMI has been shown in the general population and in obesity cohorts, we hypothesized that this polymorphism might also act through an elevated BMI on the development of coronary artery disease (CAD) or myocardial infarction (MI). We pursued two strategies: First, the polymorphism rs7566605 was investigated for association with BMI, CAD/MI, and cardiovascular risk factors in a large German cohort at high risk for CAD and MI (n = 1,460 MI patients) as compared to unrelated healthy controls (n = 1,215); second, we extended our analyses on the families of MI patients and performed family-based association testing (n = 5,390 individuals). The polymorphism rs7566605 was analyzed using TaqMan technology. No deviation from Hardy-Weinberg equilibrium could be observed, and the call rate was 98.2%. No significant associations of rs7566605 with CAD/MI, BMI, and classical cardiovascular risk factors could be detected in the full sample size or in the subgroups. A total of 6,878 individuals were investigated in a population of German MI patients and their family members. Although the number of individuals was large enough, no influence of the rs7566605 INSIG2 polymorphism was detected on BMI and CAD/MI. We therefore conclude that in our sample the SNP rs7566605 near the INSIG2 gene does not influence BMI and is not associated directly with CAD/MI or indirectly through cardiovascular risk factors.
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Affiliation(s)
- Silke Wiedmann
- Klinik und Poliklinik für Innere Medizin II, Universitätsklinikum Regensburg, Regensburg, Germany
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Bressler J, Fornage M, Hanis CL, Kao WHL, Lewis CE, McPherson R, Dent R, Mosley TH, Pennacchio LA, Boerwinkle E. The INSIG2 rs7566605 genetic variant does not play a major role in obesity in a sample of 24,722 individuals from four cohorts. BMC MEDICAL GENETICS 2009; 10:56. [PMID: 19523229 PMCID: PMC2706232 DOI: 10.1186/1471-2350-10-56] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 11/25/2008] [Accepted: 06/12/2009] [Indexed: 02/08/2023]
Abstract
Background In a genome-wide association study performed in the Framingham Offspring Cohort, individuals homozygous for the rs7566605 C allele located upstream of insulin-induced gene 2 (INSIG2) were reported to incur an increased risk of obesity. This finding was later replicated in four out of five populations examined. The goal of the study reported here was to assess the role of the INSIG2 single nucleotide polymorphism (SNP) in susceptibility to obesity in the prospective longitudinal Atherosclerosis Risk in Communities (ARIC) study (n = 14,566) and in three other cohorts: the Coronary Artery Risk Development in Young Adults (CARDIA) study (n = 3,888), the Genetic Epidemiology Network of Arteriopathy (GENOA) study (n = 4,766), and extremely obese and lean individuals ascertained at the University of Ottawa (n = 1,502). The combined study sample is comprised of 24,722 white, African-American, and Mexican-American participants. Methods Differences in mean body mass index (BMI) and other anthropometric measures including weight, waist circumference, and waist-to-hip ratio were assessed by a general linear model in individuals categorized by INSIG2 rs7566605 genotype. Multivariable logistic regression was used to predict the risk of obesity (BMI ≥ 30 kg/m2). Results There was no discernable variation in the frequencies of the three INSIG2 SNP genotypes observed between white, Hispanic, and African-American obese individuals and non-obese study subjects. When the relationship between rs7566605 and BMI considered either as a categorical variable or a continuous variable was examined, no significant association with obesity was found for participants in any of the four study populations or in a combined analysis (p = 0.38) under a recessive genetic model. There was also no association between the INSIG2 polymorphism and the obesity-related quantitative traits except for a reduced waist-to-hip ratio in white ARIC study participants homozygous for the C allele, and an increased waist-to-hip ratio in African-Americans in the ARIC cohort with the same genotype (p = 0.04 and p = 0.01, respectively). An association with waist-to-hip ratio was not seen when the combined study sample was analyzed (p = 0.74). Conclusion These results suggest that the INSIG2 rs7566605 variant does not play a major role in determining obesity risk in a racially and ethnically diverse sample of 24,722 individuals from four cohorts.
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Affiliation(s)
- Jan Bressler
- Human Genetics Center, University of Texas Health Science Center at Houston, Houston, TX 77030, USA.
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Wu AC, Gillman MW, Taveras EM, Litonjua AA. INSIG2 is Associated with Lower Gain in Weight-for-Length Between Birth and Age 6 Months. CLINICAL MEDICINE. PEDIATRICS 2009; 3:33-37. [PMID: 20354568 PMCID: PMC2846639 DOI: 10.4137/cmped.s2279] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Researchers have described the association of a common DNA polymorphism, rs7566605, near INSIG2 (insulin-induced gene 2) with obesity in multiple independent populations that include subjects ages 11-60 years.1 To our knowledge, no studies have examined the association of this polymorphism with weight status during early childhood. We explored the association of the rs7566605 polymorphism with weight-for-length among 319 children at 6 months and 3 years participating in Project Viva, a pre-birth cohort study. In contrast to studies of older individuals, CC homozygosity was associated with lower gain in weight-for-length z-score between birth and age 6 months than GG homozygosity or GC heterozygosity. At age 3, we did not find an association. The association of INSIG2 gene with obesity may change direction with age.
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Affiliation(s)
- Ann Chen Wu
- Center for Child Health Care Studies, Department of Ambulatory Care and Prevention, Harvard Pilgrim Health Care and Harvard Medical School, Boston, Massachusetts, U.S.A
- Division of General Pediatrics, Children’s Hospital, Boston, Massachusetts, U.S.A
| | - Matthew W. Gillman
- Center for Child Health Care Studies, Department of Ambulatory Care and Prevention, Harvard Pilgrim Health Care and Harvard Medical School, Boston, Massachusetts, U.S.A
- Department of Nutrition, Harvard School of Public Health, Massachusetts, U.S.A
| | - Elsie M. Taveras
- Center for Child Health Care Studies, Department of Ambulatory Care and Prevention, Harvard Pilgrim Health Care and Harvard Medical School, Boston, Massachusetts, U.S.A
- Division of General Pediatrics, Children’s Hospital, Boston, Massachusetts, U.S.A
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Orkunoglu-Suer FE, Gordish-Dressman H, Clarkson PM, Thompson PD, Angelopoulos TJ, Gordon PM, Moyna NM, Pescatello LS, Visich PS, Zoeller RF, Harmon B, Seip RL, Hoffman EP, Devaney JM. INSIG2 gene polymorphism is associated with increased subcutaneous fat in women and poor response to resistance training in men. BMC MEDICAL GENETICS 2008; 9:117. [PMID: 19105843 PMCID: PMC2646703 DOI: 10.1186/1471-2350-9-117] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/13/2008] [Accepted: 12/23/2008] [Indexed: 01/27/2023]
Abstract
Background A common SNP upstream of the INSIG2 gene, rs7566605 (g.-10,1025G>C, Chr2:118,552,255, NT_022135.15), was reported to be associated with obesity (Body Mass Index, [BMI]) in a genome-wide association scan using the Framingham Heart Study but has not been reproduced in other cohorts. As BMI is a relatively insensitive measure of adiposity that is subject to many confounding variables, we sought to determine the relationship between the INSIG2 SNP and subcutaneous fat volumes measured by MRI in a young adult population. Methods We genotyped the INSIG2 SNP rs7566605 in college-aged population enrolled in a controlled resistance-training program, (the Functional Polymorphism Associated with Human Muscle Size and Strength, FAMuSS cohort, n = 752 volunteers 18–40 yrs). In this longitudinal study, we examined the effect of the INSIG2 polymorphism on subcutaneous fat and muscle volumes of the upper arm measured by magnetic resonance imaging (MRI) before and after 12 wks of resistance training. Gene/phenotype associations were tested using an analysis of covariance model with age and weight as covariates. Further, the % variation in each phenotype attributable to genotype was determined using hierarchical models and tested with a likelihood ratio test. Results Women with a copy of the C allele had higher levels of baseline subcutaneous fat (GG: n = 139; 243473 ± 5713 mm3 vs. GC/CC: n = 181; 268521 ± 5003 mm3; p = 0.0011); but men did not show any such association. Men homozygous for the G ancestral allele showed a loss of subcutaneous fat, while those with one or two copies of the C allele gained a greater percentage of subcutaneous fat with resistance training (GG: n = 103; 1.02% ± 1.74% vs. GC/CC: n = 93; 6.39% ± 1.82%; p = 0.035). Conclusion Our results show that the INSIG2 rs7566605 polymorphism underlies variation in subcutaneous adiposity in young adult women and suppresses the positive effects of resistance training on men. This supports and extends the original finding that there is an association between measures of obesity and INSIG2 rs7566605 and further implicates this polymorphism in fat regulation.
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Affiliation(s)
- Funda E Orkunoglu-Suer
- Research Center for Genetic Medicine, Children's National Medical Center, Washington, DC 20010, USA.
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Wang HJ, Zhang H, Zhang SW, Pan YP, Ma J. Association of the common genetic variant upstream of INSIG2 gene with obesity related phenotypes in Chinese children and adolescents. BIOMEDICAL AND ENVIRONMENTAL SCIENCES : BES 2008; 21:528-536. [PMID: 19263810 DOI: 10.1016/s0895-3988(09)60013-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
OBJECTIVE To study the association between the rs7566605 variant of INSIG2 and obesity-related phenotypes in Chinese children and adolescents. METHODS The study sample consisted of two independent cohorts of Chinese children and adolescents. Anthropometric indices, lipids, blood pressure, fasting glucose, insulin and percentage of fat mass were determined. PCR with restriction fragment length polymorphism analysis was performed for genotyping the rs7566605 variant. RESULTS In each of the two independent cohorts, no significant association was observed between rs7566605 and obesity under additive, dominant or recessive model. We also did not detect any difference in the genotype frequency between all the obese children and controls. Furthermore, we did not find evidence of an association between body composition indices and metabolic phenotypes in all children. However, the triglyceride level of CC homozygotes was significantly higher than that of GG+GC genotypes in obese children (P=0.022). Additionally, we observed a non-significant trend of severe obesity in a post-hoc test. CONCLUSION INSIG2 rs7566605 variant is not associated Chinese childhood obesity in two independent cohorts. Further study is needed to verify the effect of rs7566605 on triglyceride in obese children.
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Affiliation(s)
- Hai-Jun Wang
- Department of Maternal and Child Health, School of Public Health, Peking University, Beijing 100191, China
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Andreasen CH, Mogensen MS, Borch-Johnsen K, Sandbæk A, Lauritzen T, Sørensen TIA, Hansen L, Almind K, Jørgensen T, Pedersen O, Hansen T. Non-replication of genome-wide based associations between common variants in INSIG2 and PFKP and obesity in studies of 18,014 Danes. PLoS One 2008; 3:e2872. [PMID: 18682847 PMCID: PMC2483934 DOI: 10.1371/journal.pone.0002872] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2008] [Accepted: 07/03/2008] [Indexed: 02/01/2023] Open
Abstract
Background The INSIG2 rs7566605 and PFKP rs6602024 polymorphisms have been identified as obesity gene variants in genome-wide association (GWA) studies. However, replication has been contradictory for both variants. The aims of this study were to validate these obesity-associations through case-control studies and analyses of obesity-related quantitative traits. Moreover, since environmental and genetic factors may modulate the impact of a genetic variant, we wanted to perform such interaction analyses. We focused on physical activity as an environmental risk factor, and on the GWA identified obesity variants in FTO (rs9939609) and near MC4R (rs17782313) as genetic risk factors. Materials and Methods The four variants were genotyped in a combined study sample comprising a total of 18,014 subject ascertained from, the population-based Inter99 cohort (n = 6,514), the ADDITION screening cohort (n = 8,662), a population-based study sample (n = 680) and a type 2 diabetic patient group (n = 2,158) from Steno Diabetes Center. Results No association with overweight, obesity or obesity-related measures was shown for either the INSIG2 rs7566605 or the PFKP rs6602024 variants. However, an interaction between the INSIG2 rs7566605 variant and the level of self-reported physical activity (pInt = 0.004) was observed. A BMI difference of 0.53 (SE 0.42) kg/m2 was found when comparing physically passive homozygous C-allele carriers with physically passive G-allele carriers. No interactions between the two variants and FTO rs9939609 and MC4R rs17782313 were observed. Conclusions The INSIG2 rs7566605 and PFKP rs6602024 polymorphisms play no apparent role in the development of common forms of obesity in the Danish population. However, if replicated, the INSIG2 rs7566605 may influence the level of BMI in combination with the level of physical activity.
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Affiliation(s)
- Camilla H. Andreasen
- Steno Diabetes Center, Copenhagen, Denmark
- Medical and Science, Developmental Projects, Novo Nordisk A/S, Bagsværd, Denmark
- * E-mail:
| | | | - Knut Borch-Johnsen
- Steno Diabetes Center, Copenhagen, Denmark
- Research Centre for Prevention and Health, Glostrup University Hospital, Glostrup, Denmark
- Faculty of Health Science, University of Aarhus, Aarhus, Denmark
| | - Annelli Sandbæk
- Department of General Practice, University of Aarhus, Aarhus, Denmark
| | - Torsten Lauritzen
- Department of General Practice, University of Aarhus, Aarhus, Denmark
| | - Thorkild I. A. Sørensen
- Institute for Preventive Medicine, Copenhagen University Hospitals, Centre for Health and Society, Copenhagen, Denmark
| | - Lars Hansen
- Bristol-Myers Squibb Co., Princeton, New Jersey, United States of America
| | - Katrine Almind
- Medical and Science, Developmental Projects, Novo Nordisk A/S, Bagsværd, Denmark
| | - Torben Jørgensen
- Research Centre for Prevention and Health, Glostrup University Hospital, Glostrup, Denmark
| | - Oluf Pedersen
- Steno Diabetes Center, Copenhagen, Denmark
- Faculty of Health Science, University of Aarhus, Aarhus, Denmark
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INSIG2 gene rs7566605 polymorphism is associated with severe obesity in Japanese. J Hum Genet 2008; 53:857-862. [PMID: 18615239 PMCID: PMC2522377 DOI: 10.1007/s10038-008-0317-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2008] [Accepted: 06/18/2008] [Indexed: 12/15/2022]
Abstract
The single nucleotide polymorphism (SNP) rs7566605 in the upstream region of the insulin-induced gene 2 (INSIG2) is associated with the obesity phenotype in many Caucasian populations. In Japanese, this association with the obesity phenotype is not clear. To investigate the relationship between rs7566605 and obesity in Japanese, we genotyped rs7566605 from severely obese subjects [n = 908, body mass index (BMI) ≥ 30 kg/m2] and normal-weight control subjects (n = 1495, BMI < 25 kg/m2). A case–control association analysis revealed that rs7566605 was significantly associated with obesity in Japanese. The P value in the minor allele recessive mode was 0.00020, and the odds ratio (OR) adjusted for gender and age was 1.61 [95% confidential interval (CI) = 1.24–2.09]. Obesity-associated phenotypes, which included the level of BMI, plasma glucose, hemoglobin A1c, total cholesterol, triglycerides, high-density lipoprotein (HDL) cholesterol, and blood pressure, were not associated with the rs7566605 genotype. Thus, rs7566605 in the upstream region of the INSIG2 gene was found to be associated with obesity, i.e., severe obesity, in Japanese.
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Abstract
PURPOSE OF REVIEW These last months, the wave of genome-wide association scans finally reached the shores of body weight and obesity complex trait. In parallel, thanks to the increasing sequencing and genotyping capacities, large studies on rare mutations can now be carried out. RECENT FINDINGS In this review, I tried to cover the most recent findings in genome-wide association analyses, the outcome of conclusions subsequently not replicated, and the weight of rare mutations with strong effects on common obesity. The strongest predictor of obesity, FTO, is responsible for 1% of the total heritability, and results from other genome-wide scans do not provide, so far, any clue of other variants of this effect size. Thus, monogenic obesity studies might well reinstall the importance of rare nonsynonymous mutations of already known genes, especially melanocortin-4 receptor gene, in the general population. Nevertheless, additional genome-wide association analyses and replication are expected to confirm these first intuitions. SUMMARY Initial results both support the common variant-common disease hypothesis because at least one such variant exists in FTO, and also tone down its importance because such variants may be fewer than expected. Moreover, having a polymorphism associated with body weight is clearly not the end but rather the beginning of a long search for the gene function and pathway.
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Affiliation(s)
- Christian Dina
- CNRS 8090-Institute of Biology, Pasteur Institute, Lille, France.
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