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This article is part of the supplement: Genetic Analysis Workshop 16

Open Access Proceedings

A quantile-based method for association mapping of quantitative phenotypes: an application to rheumatoid arthritis phenotypes

Saurabh Ghosh*, Krishna Rao Sanapala, Abhik Ghosh and Sujatro Chakladar

Author Affiliations

Human Genetics Unit, Indian Statistical Institute, Kolkata, India

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BMC Proceedings 2009, 3(Suppl 7):S18  doi:

Published: 15 December 2009

Abstract

Genetic association of population-based quantitative trait data has traditionally been analyzed using analysis of variance (ANOVA). However, violations of certain statistical assumptions may lead to false-positive association results. In this study, we have explored model-free alternatives to ANOVA using correlations between allele frequencies in the different quantile intervals of the quantitative trait and the quantile values. We performed genome-wide association scans on anti-cyclic citrullinated peptide and rheumatoid factor-immunoglobulin M, two quantitative traits correlated with rheumatoid arthritis, using the data provided in Genetic Analysis Workshop 16. Both the quantitative traits exhibited significant evidence of association on Chromosome 6, although not in the human leukocyte antigen region which is known to harbor a major gene predisposing to rheumatoid arthritis. We found that while a majority of the significant findings using the asymptotic thresholds of ANOVA was not validated using permutations, a relatively higher proportion of the significant findings using the asymptotic cut-offs of the correlation statistic were validated using permutations.