@article {522, title = {Whole exome sequencing analysis in severe chronic obstructive pulmonary disease.}, journal = {Hum Mol Genet}, volume = {27}, year = {2018}, month = {2018 11 01}, pages = {3801-3812}, abstract = {

Chronic obstructive pulmonary disease (COPD), one of the leading causes of death worldwide, is substantially influenced by genetic factors. Alpha-1 antitrypsin deficiency demonstrates that rare coding variants of large effect can influence COPD susceptibility. To identify additional rare coding variants in patients with severe COPD, we conducted whole exome sequencing analysis in 2543 subjects from two family-based studies (Boston Early-Onset COPD Study and International COPD Genetics Network) and one case-control study (COPDGene). Applying a gene-based segregation test in the family-based data, we identified significant segregation of rare loss of function variants in TBC1D10A and RFPL1 (P-value~<~2x10-6), but were unable to find similar variants in the case-control study. In single-variant, gene-based and pathway association analyses, we were unable to find significant findings that replicated or were significant in meta-analysis. However, we found that the top results in the two datasets were in proximity to each other in the protein-protein interaction network (P-value~=~0.014), suggesting enrichment of these results for similar biological processes. A network of these association results and their neighbors was significantly enriched in the transforming growth factor beta-receptor binding and cilia-related pathways. Finally, in a more detailed examination of candidate genes, we identified individuals with putative high-risk variants, including patients harboring homozygous mutations in genes associated with cutis laxa and Niemann-Pick Disease Type C. Our results likely reflect heterogeneity of genetic risk for COPD along with limitations of statistical power and functional annotation, and highlight the potential of network analysis to gain insight into genetic association studies.

}, keywords = {Adolescent, Adult, Aged, Case-Control Studies, DNA Mutational Analysis, Female, Genetic Association Studies, Genetic Predisposition to Disease, Humans, Male, Middle Aged, Mutation, Polymorphism, Single Nucleotide, Pulmonary Disease, Chronic Obstructive, Whole Exome Sequencing, Young Adult}, issn = {1460-2083}, doi = {10.1093/hmg/ddy269}, author = {Qiao, Dandi and Ameli, Asher and Prokopenko, Dmitry and Chen, Han and Kho, Alvin T and Parker, Margaret M and Morrow, Jarrett and Hobbs, Brian D and Liu, Yanhong and Beaty, Terri H and Crapo, James D and Barnes, Kathleen C and Nickerson, Deborah A and Bamshad, Michael and Hersh, Craig P and Lomas, David A and Agusti, Alvar and Make, Barry J and Calverley, Peter M A and Donner, Claudio F and Wouters, Emiel F and Vestbo, J{\o}rgen and Par{\'e}, Peter D and Levy, Robert D and Rennard, Stephen I and Tal-Singer, Ruth and Spitz, Margaret R and Sharma, Amitabh and Ruczinski, Ingo and Lange, Christoph and Silverman, Edwin K and Cho, Michael H} } @article {98, title = {Exome Sequencing Analysis in Severe, Early-Onset Chronic Obstructive Pulmonary Disease.}, journal = {Am J Respir Crit Care Med}, volume = {193}, year = {2016}, month = {2016 06 15}, pages = {1353-63}, abstract = {

RATIONALE: Genomic regions identified by genome-wide association studies explain only a small fraction of heritability for chronic obstructive pulmonary disease (COPD). Alpha-1 antitrypsin deficiency shows that rare coding variants of large effect also influence COPD susceptibility. We hypothesized that exome sequencing in families identified through a proband with severe, early-onset COPD would identify additional rare genetic determinants of large effect.

OBJECTIVES: To identify rare genetic determinants of severe COPD.

METHODS: We applied filtering approaches to identify potential causal variants for COPD in whole exomes from 347 subjects in 49 extended pedigrees from the Boston Early-Onset COPD Study. We assessed the power of this approach under different levels of genetic heterogeneity using simulations. We tested genes identified in these families using gene-based association tests in exomes of 204 cases with severe COPD and 195 resistant smokers from the COPDGene study. In addition, we examined previously described loci associated with COPD using these datasets.

MEASUREMENTS AND MAIN RESULTS: We identified 69 genes with predicted deleterious nonsynonymous, stop, or splice variants that segregated with severe COPD in at least two pedigrees. Four genes (DNAH8, ALCAM, RARS, and GBF1) also demonstrated an increase in rare nonsynonymous, stop, and/or splice mutations in cases compared with resistant smokers from the COPDGene study; however, these results were not statistically significant. We demonstrate the limitations of the power of this approach under genetic heterogeneity through simulation.

CONCLUSIONS: Rare deleterious coding variants may increase risk for COPD, but multiple genes likely contribute to COPD susceptibility.

}, keywords = {Adult, alpha 1-Antitrypsin Deficiency, Boston, Exome, Female, Genetic Predisposition to Disease, Genome-Wide Association Study, Humans, Male, Middle Aged, Pulmonary Disease, Chronic Obstructive, Severity of Illness Index}, issn = {1535-4970}, doi = {10.1164/rccm.201506-1223OC}, author = {Qiao, Dandi and Lange, Christoph and Beaty, Terri H and Crapo, James D and Barnes, Kathleen C and Bamshad, Michael and Hersh, Craig P and Morrow, Jarrett and Pinto-Plata, Victor M and Marchetti, Nathaniel and Bueno, Raphael and Celli, Bartolome R and Criner, Gerald J and Silverman, Edwin K and Cho, Michael H} } @article {415, title = {Increasing Generality and Power of Rare-Variant Tests by Utilizing Extended Pedigrees.}, journal = {Am J Hum Genet}, volume = {99}, year = {2016}, month = {2016 Oct 06}, pages = {846-859}, abstract = {

Recently, multiple studies have performed whole-exome or whole-genome sequencing to identify groups of rare variants associated with complex traits and diseases. They have primarily utilized case-control study designs that often require thousands of individuals to reach acceptable statistical power. Family-based studies can be more powerful because a rare variant can be enriched in an extended pedigree and segregate with the phenotype. Although many methods have been proposed for using family data to discover rare variants involved in a disease, a majority of them focus on a specific pedigree structure and are designed to analyze either binary or continuously measured outcomes. In this article, we propose RareIBD, a general and powerful approach to identifying rare variants involved in disease susceptibility. Our method can be applied to large extended families of arbitrary structure, including pedigrees with only affected individuals. The method accommodates both binary and quantitative traits. A series of simulation experiments suggest that RareIBD is a powerful test that outperforms existing approaches. In addition, our method accounts for individuals in top generations, which are not usually genotyped in extended families. In contrast to available statistical tests, RareIBD generates accurate p values even when genetic data from these individuals are missing. We applied RareIBD, as well as other methods, to two extended family datasets generated by different genotyping technologies and representing different ethnicities. The analysis of real data confirmed that RareIBD is the only method that properly controls type I error.

}, keywords = {Datasets as Topic, Ethnic Groups, Family, Female, Genetic Predisposition to Disease, Genetic Variation, Genotype, Humans, Male, Models, Genetic, Pedigree, Phenotype, Research Design}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2016.08.015}, author = {Sul, Jae Hoon and Cade, Brian E and Cho, Michael H and Qiao, Dandi and Silverman, Edwin K and Redline, Susan and Sunyaev, Shamil} }