title: An interactive mutation database for human coagulation factor IX provides novel insights into the phenotypes and genetics of hemophilia B.
abstract: BACKGROUND
  Factor IX (FIX) is important in the coagulation cascade, being activated to FIXa on cleavage. Defects in the human F9 gene frequently lead to hemophilia B.
  
  
  OBJECTIVE
  To assess 1113 unique F9 mutations corresponding to 3721 patient entries in a new and up-to-date interactive web database alongside the FIXa protein structure.
  
  
  METHODS
  The mutations database was built using MySQL and structural analyses were based on a homology model for the human FIXa structure based on closely-related crystal structures.
  
  
  RESULTS
  Mutations have been found in 336 (73%) out of 461 residues in FIX. There were 812 unique point mutations, 182 deletions, 54 polymorphisms, 39 insertions and 26 others that together comprise a total of 1113 unique variants. The 64 unique mild severity mutations in the mature protein with known circulating protein phenotypes include 15 (23%) quantitative type I mutations and 41 (64%) predominantly qualitative type II mutations. Inhibitors were described in 59 reports (1.6%) corresponding to 25 unique mutations.
  
  
  CONCLUSIONS
  The interactive database provides insights into mechanisms of hemophilia B. Type II mutations are deduced to disrupt predominantly those structural regions involved with functional interactions. The interactive features of the database will assist in making judgments about patient management.
authors.affiliation: Division of Biosciences, Research Department of Structural and Molecular Biology, University College London, London, UK.
authors.forename: P M
authors.initials: PM
authors.lastname: Rallapalli
authors.forename: G
authors.initials: G
authors.lastname: Kemball-Cook
authors.forename: E G
authors.initials: EG
authors.lastname: Tuddenham
authors.forename: K
authors.initials: K
authors.lastname: Gomez
authors.forename: S J
authors.initials: SJ
authors.lastname: Perkins
mesh_terms: D000595:Amino Acid Sequence; D001777:Blood Coagulation / Q000235:genetics*; D019295:Computational Biology; D018360:Crystallography, X-Ray; D004252:DNA Mutational Analysis; D030541:Databases, Genetic; D005164:Factor IX / Q000737:chemistry / Q000235:genetics*; D015949:Factor IXa / Q000235:genetics; D020022:Genetic Predisposition to Disease; D002836:Hemophilia B / Q000097:blood / Q000235:genetics*; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D011110:Polymorphism, Genetic; D011487:Protein Conformation; D012720:Severity of Illness Index; D013329:Structure-Activity Relationship
chemical_list: D005164:Factor IX; D015949:Factor IXa
keywords: bioinformatics; coagulation factor IX; database; hemophilia B; models; molecular; mutations; phenotypes