title: HLA-DQ allele competition in narcolepsy: a comment on Tafti et al. DQB1 locus alone explains most of the risk and protection in narcolepsy with cataplexy in Europe.
abstract: OBJECTIVE
  Although HLA-DQB1*06:02 is the strongest predisposing genetic factor for narcolepsy, the effect of this gene must be considered alongside that of its polymorphic partner, DQA1. In this paper, we extend an analysis of the effect of HLA-DQB1 on narcolepsy risk published recently by Tafti et al.
  
  
  RESULTS
  Imputing allelic variation at the level of HLA-DQA1, we show that this locus also has a considerable effect on disease susceptibility. Our data are also compatible with previous findings in multi-ethnic group data sets showing that allele competition effects within the DQ1 group determine the amount of DQ0602 (the DQA1*01:02/DQB1*06:02 heterodimer), and consequently, the risk of developing narcolepsy. We also found an independent predisposing effect of DQB1*03:01 via a currently unknown mechanism.
  
  
  CONCLUSIONS
  Both DQA1 and DQB1 influence narcolepsy risk.
authors.affiliation: Stanford University Center for Sleep Sciences, Palo Alto, CA.
authors.forename: Hanna M
authors.initials: HM
authors.lastname: Ollila
authors.affiliation: Department of Pathology, Stanford Medical School Blood Center, Stanford, CA.
authors.forename: Marcelo
authors.initials: M
authors.lastname: Fernandez-Vina
authors.affiliation: Stanford University Center for Sleep Sciences, Palo Alto, CA.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Mignot
mesh_terms: D002385:Cataplexy / Q000235:genetics*; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D059866:HLA-DQ beta-Chains / Q000235:genetics*; D006801:Humans; D009290:Narcolepsy / Q000235:genetics*
chemical_list: D059866:HLA-DQ beta-Chains