title: Narcolepsy in Southern Chinese patients: clinical characteristics, HLA typing and seasonality of birth.
abstract: OBJECTIVE
  To report clinical characteristics, human leukocyte antigen (HLA) typing and seasonality of birth of a series of 54 Southern Chinese patients suffering from narcolepsy.
  
  
  METHODS
  All subjects underwent detailed medical and psychiatric interviews and a standardised nocturnal polysomnogram followed by a daytime Multiple Sleep Latency Test. Each subject also completed a set of sleep questionnaires. HLA typing was performed in 91% of subjects.
  
  
  RESULTS
  A total of 78% and 22% of patients were diagnosed with suffering from cataplectic and non-cataplectic narcolepsy, respectively. The majority (n = 47, 87%) of patients were referred to our sleep clinic for excessive daytime sleepiness (EDS). The cataplectic narcolepsy differed from non-cataplectic narcolepsy by having more rapid eye movement (REM)-related clinical symptoms (more sleep paralysis and sleep-related hallucination) and sleep disturbances (shorter REM latency), as well as tighter association with HLA DQB1*0602. A bi-modal peak pattern was observed at 11 and 39 years old. A similar bi-modal pattern also occurred for EDS and cataplexy. Excess winter births were observed for this series of patients. 81% of patients with cataplectic narcolepsy were DQB1*0602-positive. There were no differences between early- and late-onset cases in the association with positive DQB1*0602 (71.4% vs 60%). Narcolepsy had prominent pernicious effects on various social, academic, family and mental aspects in our patients.
  
  
  CONCLUSIONS
  In our Southern Chinese narcolepsy series, bi-modal peak pattern of age of onset, excess winter birth and tight association of HLA DQB1*0602 with cataplectic narcolepsy were found.
authors.affiliation: Department of Psychiatry, Shatin Hospital, The Chinese University of Hong Kong, Prince of Wales and Shatin Hospitals, Shatin, Hong Kong SAR. ykwing@cuhk.edu.hk
authors.forename: Y K
authors.initials: YK
authors.lastname: Wing
authors.forename: L
authors.initials: L
authors.lastname: Chen
authors.forename: S Y Y
authors.initials: SY
authors.lastname: Fong
authors.forename: M H L
authors.initials: MH
authors.lastname: Ng
authors.forename: C K W
authors.initials: CK
authors.lastname: Ho
authors.forename: S H
authors.initials: SH
authors.lastname: Cheng
authors.forename: N L S
authors.initials: NL
authors.lastname: Tang
authors.forename: A M
authors.initials: AM
authors.lastname: Li
mesh_terms: D000293:Adolescent; D000328:Adult; D044466:Asian People / Q000706:statistics & numerical data*; D002391:Catchment Area, Health; D002648:Child; D002681:China / Q000453:epidemiology; D005260:Female; D005838:Genotype; D006680:HLA Antigens / Q000276:immunology*; D006683:HLA-DQ Antigens / Q000276:immunology; D059866:HLA-DQ beta-Chains; D006801:Humans; D008297:Male; D008562:Membrane Glycoproteins / Q000276:immunology; D008875:Middle Aged; D009290:Narcolepsy / Q000453:epidemiology* / Q000235:genetics / Q000276:immunology*; D036801:Parturition; D015995:Prevalence; D012621:Seasons
chemical_list: D006680:HLA Antigens; D006683:HLA-DQ Antigens; D059866:HLA-DQ beta-Chains; C069051:HLA-DQB1 antigen; D008562:Membrane Glycoproteins