title: Joint analysis of multiple blood pressure phenotypes in GAW19 data by using a multivariate rare-variant association test.
abstract: BACKGROUND
  Large-scale sequencing studies often measure many related phenotypes in addition to the genetic variants. Joint analysis of multiple phenotypes in genetic association studies may increase power to detect disease-associated loci.
  
  
  METHODS
  We apply a recently developed multivariate rare-variant association test to the Genetic Analysis Workshop 19 data in order to test associations between genetic variants and multiple blood pressure phenotypes simultaneously. We also compare this multivariate test with a widely used univariate test that analyzes phenotypes separately.
  
  
  RESULTS
  The multivariate test identified 2 genetic variants that have been previously reported as associated with hypertension or coronary artery disease. In addition, our region-based analyses also show that the multivariate test tends to give smallerpvalues than the univariate test.
  
  
  CONCLUSIONS
  Hence, the multivariate test has potential to improve test power, especially when multiple phenotypes are correlated.
authors.affiliation: Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, QC H3A 1A2 Canada ; Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, QC H3T 1E2 Canada.
authors.forename: Jianping
authors.initials: J
authors.lastname: Sun
authors.affiliation: Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, QC H3A 1A2 Canada.
authors.forename: Sahir R
authors.initials: SR
authors.lastname: Bhatnagar
authors.affiliation: Département de Mathématiques, Université du Québec à Montréal, Montréal, QC H2X 3Y7 Canada.
authors.forename: Karim
authors.initials: K
authors.lastname: Oualkacha
authors.affiliation: Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, QC H3A 1A2 Canada.
authors.forename: Antonio
authors.initials: A
authors.lastname: Ciampi
authors.affiliation: Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, QC H3A 1A2 Canada ; Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, QC H3T 1E2 Canada ; Department of Oncology, McGill University, Montreal, QC H2W 1S6 Canada ; Department of Human Genetics, McGill University, Montreal, QC H3A 1B1 Canada.
authors.forename: Celia M T
authors.initials: CM
authors.lastname: Greenwood