DQB1*0602 and DQA1*0102 (DQ1) are better markers than DR2 for narcolepsy in Caucasian and black Americans.

In the present study, we tested 19 Caucasian and 28 Black American narcoleptics for the presence of the human leucocyte antigen (HLA) DQB10602 and DQA10102 (DQ1) genes using a specific polymerase chain reaction (PCR)-oligotyping technique. A similar technique was also used to identify DRB11501 and DRB11503 (DR2). Results indicate that all but one Caucasian patient (previously identified) were DRB11501 (DR2) and DQB10602/DQA1102 (DQ1) positive. In Black Americans, however, DRB11501 (DR2) was a poor marker for narcolepsy. Only 75% of patients were DR2 positive, most of them being DRB11503, but not DRB11501 positive. DQB10602 was found in all but one Black narcoleptic patient. The clinical and polygraphic results for this patient were typical, thus confirming the existence of a rare, but genuine form of DQB10602 negative narcolepsy. These results demonstrate that DQB10602/DQA10102 is the best marker for narcolepsy across all ethnic groups.