On the association of common and rare genetic variation influencing body mass index: a combined SNP and CNV analysis
- PMID: 24884913
- PMCID: PMC4035084
- DOI: 10.1186/1471-2164-15-368
On the association of common and rare genetic variation influencing body mass index: a combined SNP and CNV analysis
Abstract
Background: As the architecture of complex traits incorporates a widening spectrum of genetic variation, analyses integrating common and rare variation are needed. Body mass index (BMI) represents a model trait, since common variation shows robust association but accounts for a fraction of the heritability. A combined analysis of single nucleotide polymorphisms (SNP) and copy number variation (CNV) was performed using 1850 European and 498 African-Americans from the Study of Addiction: Genetics and Environment. Genetic risk sum scores (GRSS) were constructed using 32 BMI-validated SNPs and aggregate-risk methods were compared: count versus weighted and proxy versus imputation.
Results: The weighted SNP-GRSS constructed from imputed probabilities of risk alleles performed best and was highly associated with BMI (p=4.3×10(-16)) accounting for 3% of the phenotypic variance. In addition to BMI-validated SNPs, common and rare BMI/obesity-associated CNVs were identified from the literature. Of the 84 CNVs previously reported, only 21-kilobase deletions on 16p12.3 showed evidence for association with BMI (p=0.003, frequency=16.9%), with two CNVs nominally associated with class II obesity, 1p36.1 duplications (OR=3.1, p=0.009, frequency 1.2%) and 5q13.2 deletions (OR=1.5, p=0.048, frequency 7.7%). All other CNVs, individually and in aggregate, were not associated with BMI or obesity. The combined model, including covariates, SNP-GRSS, and 16p12.3 deletion accounted for 11.5% of phenotypic variance in BMI (3.2% from genetic effects). Models significantly predicted obesity classification with maximum discriminative ability for morbid-obesity (p=3.15×10(-18)).
Conclusion: Results show that incorporating validated effect sizes and allelic probabilities improve prediction algorithms. Although rare-CNVs did not account for significant phenotypic variation, results provide a framework for integrated analyses.
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References
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- Centers for Disease Control and Prevention [http://www.cdc.gov]
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- U01 HG004446/HG/NHGRI NIH HHS/United States
- U01 HG004422/HG/NHGRI NIH HHS/United States
- K02 AA018755/AA/NIAAA NIH HHS/United States
- U10 AA008401/AA/NIAAA NIH HHS/United States
- HHSN862200782096C/PHS HHS/United States
- R25 DA026119/DA/NIDA NIH HHS/United States
- U01 HG004438/HG/NHGRI NIH HHS/United States
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- T32 MH020030/MH/NIMH NIH HHS/United States
- R01 DA019963/DA/NIDA NIH HHS/United States
- R01 DA013423/DA/NIDA NIH HHS/United States
- DA26119/DA/NIDA NIH HHS/United States
- P60 AA003510/AA/NIAAA NIH HHS/United States
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