Case-control study with narcoleptic patients and healthy controls who, like the patients, possess both HLA-DRB1*1501 and -DQB1*0602

In previous studies, we suggested that the tumor necrosis factor (TNF-alpha and its receptor 2 (TNFR2) genes could be associated with the susceptibili ty to human narcolepsy, and that haplotype carrying DRB1*1502 had a negativ e association with the disorder. To further evaluate these associations, we herein compared narcoleptic patients with healthy individuals who, like th e patients, possessed both DRB1*1501 and DQB1*0602. Results agreed with the negative association of DRB1*1502 and positive association of the TNF-alph a(-857T) and TNFR2-196R combination with the disorder. In addition, a signi ficant association of the TNF-alpha(-857T) homozygote with the disorder and an increase in a rare haplotype carrying DRB1*1501 and TNF-alpha(-857T) in the patients were also observed in the present study.