HLA-DQB1-ASTERISK-0602 HOMOZYGOSITY INCREASES RELATIVE RISK FOR NARCOLEPSY BUT NOT DISEASE SEVERITY IN 2 ETHNIC-GROUPS

Narcolepsy is a neurological disorder known to be tightly associated w ith HLA-DQA10102 and DQB1*0602. In this study, we have examined if ho mozygosity for DQB10602 increases disease susceptibility and/or sever ity. Patients diagnosed at Stanford University (n = 160) or enrolled i n a multicenter clinical trial (n = 509) were included in this analysi s. In both African-Americans and Caucasian-Americans with or without c ataplexy, a significantly higher than expected number of subjects were DQB10602 homozygotes. Relative risks were 2-4 times higher in DQB1*0 602 homozygotes vs heterozygotes across all patient groups. In contras t, symptom severity did not differ between DQB10602 homozygous and he terozygous subjects. These results indicate that HLA-DQB10602 homozyg osity increases susceptibility to narcolepsy but does not appear to in fluence disease severity.