Abstract
Exome sequencing has become a powerful and effective strategy for the discovery of genes underlying Mendelian disorders1. However, use of exome sequencing to identify variants associated with complex traits has been more challenging, partly because the sample sizes needed for adequate power may be very large2. One strategy to increase efficiency is to sequence individuals who are at both ends of a phenotype distribution (those with extreme phenotypes). Because the frequency of alleles that contribute to the trait are enriched in one or both phenotype extremes, a modest sample size can potentially be used to identify novel candidate genes and/or alleles3. As part of the National Heart, Lung, and Blood Institute (NHLBI) Exome Sequencing Project (ESP), we used an extreme phenotype study design to discover that variants in DCTN4, encoding a dynactin protein, are associated with time to first P. aeruginosa airway infection, chronic P. aeruginosa infection and mucoid P. aeruginosa in individuals with cystic fibrosis.
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References
Bamshad, M.J. et al. Exome sequencing as a tool for Mendelian disease gene discovery. Nat. Rev. Genet. 12, 745–755 (2011).
Stitziel, N.O., Kiezun, A. & Sunyaev, S. Computational and statistical approaches to analyzing variants identified by exome sequencing. Genome Biol. 12, 227 (2011).
Lanktree, M.B., Hegele, R.A., Schork, N.J. & Spence, J.D. Extremes of unexplained variation as a phenotype: an efficient approach for genome-wide association studies of cardiovascular disease. Circ. Cardiovasc. Genet. 3, 215–221 (2010).
Gibson, R.L., Burns, J.L. & Ramsey, B.W. Pathophysiology and management of pulmonary infections in cystic fibrosis. Am. J. Respir. Crit. Care Med. 168, 918–951 (2003).
Emerson, J., Rosenfeld, M., McNamara, S., Ramsey, B. & Gibson, R.L. Pseudomonas aeruginosa and other predictors of mortality and morbidity in young children with cystic fibrosis. Pediatr. Pulmonol. 34, 91–100 (2002).
Proesmans, M. et al. Evaluating the “Leeds criteria” for Pseudomonas aeruginosa infection in a cystic fibrosis centre. Eur. Respir. J. 27, 937–943 (2006).
Johansen, H.K. et al. Antibody response to Pseudomonas aeruginosa in cystic fibrosis patients: a marker of therapeutic success?—a 30-year cohort study of survival in Danish CF patients after onset of chronic P. aeruginosa lung infection. Pediatr. Pulmonol. 37, 427–432 (2004).
Treggiari, M.M. et al. Early anti-pseudomonal acquisition in young patients with cystic fibrosis: rationale and design of the EPIC clinical trial and observational study. Contemp. Clin. Trials 30, 256–268 (2009).
Wright, F.A. et al. Genome-wide association and linkage identify modifier loci of lung disease severity in cystic fibrosis at 11p13 and 20q13.2. Nat. Genet. 43, 539–546 (2011).
Morris, A.P. & Zeggini, E. An evaluation of statistical approaches to rare variant analysis in genetic association studies. Genet. Epidemiol. 34, 188–193 (2010).
Green, D.M. et al. Mutations that permit residual CFTR function delay acquisition of multiple respiratory pathogens in CF patients. Respir. Res. 11, 140 (2010).
Lee, T.W., Brownlee, K.G., Conway, S.P., Denton, M. & Littlewood, J.M. Evaluation of a new definition for chronic Pseudomonas aeruginosa infection in cystic fibrosis patients. J. Cyst. Fibros. 2, 29–34 (2003).
Li, Z. et al. Longitudinal development of mucoid Pseudomonas aeruginosa infection and lung disease progression in children with cystic fibrosis. J. Am. Med. Assoc. 293, 581–588 (2005).
Kimura, S., Noda, T. & Yoshimori, T. Dynein-dependent movement of autophagosomes mediates efficient encounters with lysosomes. Cell Struct. Funct. 33, 109–122 (2008).
Haspel, J.A. & Choi, A.M. Autophagy: a core cellular process with emerging links to pulmonary disease. Am. J. Respir. Crit. Care Med. 184, 1237–1246 (2011).
Yuan, K. et al. Autophagy plays an essential role in the clearance of Pseudomonas aeruginosa by alveolar macrophages. J. Cell Sci. 125, 507–515 (2012).
Yu, L., Martinez, F.D. & Klimecki, W.T. Automated high-throughput sex-typing assay. Biotechniques 37, 662–664 (2004).
Li, H. & Durbin, R. Fast and accurate short read alignment with Burrows-Wheeler transform. Bioinformatics 25, 1754–1760 (2009).
DePristo, M.A. et al. A framework for variation discovery and genotyping using next-generation DNA sequencing data. Nat. Genet. 43, 491–498 (2011).
Acknowledgements
We thank the families for their participation and the EPIC study site investigators and research coordinators (Supplementary Note) for their assistance. We thank A. Bigham, S. Leal, M. Rosenfeld, B. Ramsey, N. Hamblett, K. Buckingham, M. McMillin, S. McNamara and S. Ruuska for technical assistance and helpful discussion. The authors wish to acknowledge the support of the NHLBI and the contributions of the research institutions, study investigators, field staff and study participants in creating this resource for biomedical research. Funding for GO ESP was provided by NHLBI grants RC2 HL-103010 (HeartGO), RC2 HL-102923 (Lung GO) and RC2 HL-102924 (Women's Health Initiative Sequencing Project (WHISP)). Exome sequencing was performed with support from NHLBI grants RC2 HL-102925 (BroadGO) and RC2 HL-102926 (SeattleGO). Our work was supported in part by grants from the Cystic Fibrosis Foundation (to R.L.G. (GIBSON07K0) and to M. Rosenfeld and R.L.G. (CFF EPIC09K0)), the US National Institutes of Health/National Human Genome Research Institute (5RO1 HG004316 to H.K.T.), and the Life Sciences Discovery Fund (2065508 and 0905001). K.C.B. was supported in part by the Mary Beryl Patch Turnbull Scholar Program.
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The project was conceived and experiments planned by M.J.B., M.J.E., M.R.K., K.C.B. and R.L.G. Review of phenotypes and sample collection were performed by M.J.B., M.J.E., R.L.G., J.E. and M.R.K. Experiments were performed by M.J.R. and D.A.N. Regulatory review and guidance was provided by H.K.T. Data analysis was performed by M.J.E., J.E., T.L., F.A.W., W.Z. and R.A.M. The manuscript was written by M.J.B., M.J.E. and R.L.G. All aspects of the study were supervised by M.J.B., M.J.E. and R.L.G.
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A full list of members and their affiliations is provided in the Supplementary Note.
A full list of members and their affiliations is provided in the Supplementary Note.
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Supplementary Tables 1–5, Supplementary Figures 1–16 and Supplementary Note (PDF 657 kb)
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Emond, M., Louie, T., Emerson, J. et al. Exome sequencing of extreme phenotypes identifies DCTN4 as a modifier of chronic Pseudomonas aeruginosa infection in cystic fibrosis. Nat Genet 44, 886–889 (2012). https://doi.org/10.1038/ng.2344
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DOI: https://doi.org/10.1038/ng.2344