title: VPA: an R tool for analyzing sequencing variants with user-specified frequency pattern.
abstract: BACKGROUND
  The massive amounts of genetic variant generated by the next generation sequencing systems demand the development of effective computational tools for variant prioritization.
  
  
  RESULTS
  VPA (Variant Pattern Analyzer) is an R tool for prioritizing variants with specified frequency pattern from multiple study subjects in next-generation sequencing study. The tool starts from individual files of variant and sequence calls and extract variants with user-specified frequency pattern across the study subjects of interest. Several position level quality criteria can be incorporated into the variant extraction. It can be used in studies with matched pair design as well as studies with multiple groups of subjects.
  
  
  CONCLUSIONS
  VPA can be used as an automatic pipeline to prioritize variants for further functional exploration and hypothesis generation. The package is implemented in the R language and is freely available from http://vpa.r-forge.r-project.org.
authors.affiliation: Department of Biostatistics, Roswell Park Cancer Institute, Buffalo, New York 14263, USA. Song.Liu@RoswellPark.org.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Hu
authors.forename: Dan
authors.initials: D
authors.lastname: Wang
authors.forename: Li
authors.initials: L
authors.lastname: Yan
authors.forename: Hua
authors.initials: H
authors.lastname: Zhao
authors.forename: Song
authors.initials: S
authors.lastname: Liu