The month-of-birth pattern in narcolepsy is moderated by cataplexy severity and may be independent of HLA-DQB1*0602.
Picchioni D, Mignot EJ, Harsh JR. The month-of-birth pattern in narcolepsy is moderated by cataplexy severity and may be independent of HLA-DQB1*0602. Sleep. 2004 Dec 15; 27(8):1471-5.