The month-of-birth pattern in narcolepsy is moderated by cataplexy severity and may be independent of HLA-DQB1*0602.
OBJECTIVE
A March peak and a September trough in the birth pattern of narcolepsy patients with clear-cut cataplexy was recently reported. The objectives of the present study were to determine whether the month-of-birth pattern would (a) vary with the presence and severity of cataplexy and (b) differ for patients positive and negative for HLA-DQB1*0602.


METHODS
Cross-sectional survey with data obtained from the clinical trials assessing the safety and efficacy of modafinil in the treatment of narcolepsy.


METHODS
Sleep clinics throughout the United States.


METHODS
A group of 530 narcolepsy patients diagnosed based on the International Classification of Sleep Disorders using clinical histories, nocturnal polysomnography, and Multiple Sleep Latency Tests.


METHODS
NA.


RESULTS
A surplus of March births and a fall-off in September births was found in narcolepsy relative to the general population. This finding was only observed when cataplexy was moderate or severe. The month-of-birth pattern was similar for HLA-DQB1*0602 positive and negative patients. A March birth and HLA-DQB1*0602 positivity were independent risk factors in a logistic regression analysis.


CONCLUSIONS
Environmental events during development may influence narcolepsy severity or the likelihood of developing the disease.
Picchioni
Dante
D
University of Southern Mississippi, Hattiesburg, USA.
Mignot
Emmanuel J
EJ
Harsh
John R
JR
D000328:Adult; D017668:Age of Onset; D000368:Aged; D001559:Benzhydryl Compounds / Q000627:therapeutic use; D001921:Brain / Q000378:metabolism; D002385:Cataplexy / Q000188:drug therapy / Q000453:epidemiology / Q000235:genetics; D000697:Central Nervous System Stimulants / Q000627:therapeutic use; D003430:Cross-Sectional Studies; D004777:Environment; D005260:Female; D005838:Genotype; D006683:HLA-DQ Antigens / Q000235:genetics*; D059866:HLA-DQ beta-Chains; D006801:Humans; D015994:Incidence; D008297:Male; D008403:Mass Screening / Q000379:methods; D008562:Membrane Glycoproteins / Q000235:genetics*; D000077408:Modafinil; D009290:Narcolepsy / Q000188:drug therapy / Q000453:epidemiology* / Q000235:genetics*; D017286:Polysomnography; D012621:Seasons; D012720:Severity of Illness Index; D012895:Sleep, REM / Q000502:physiology; D014481:United States / Q000453:epidemiology
D001559:Benzhydryl Compounds; D000697:Central Nervous System Stimulants; D006683:HLA-DQ Antigens; D059866:HLA-DQ beta-Chains; C069051:HLA-DQB1 antigen; D008562:Membrane Glycoproteins; D000077408:Modafinil