Indeed, erroneous HLA-disease associations have been established due to LD, such as in the case of narcolepsy, where predisposing factors had been mistakenly attributed to HLA-DRB1*15, and later were found to be associated to the HLA-DQ genes that are in LD with DRB1*15 (6). The gene discussed is HLA-DRB1; the disease is narcolepsy.