The HLA-DRB1, -DQB1, and -DQA1 genes also were among the 10 top-ranking pleiotropic genes in the Chesmore et al. (2018) study and, together with the MTCO3P1 variants, might be associated with systemic lupus erythematosus, T1D, immunoglobulin A nephropathy, Crohn’s disease, multiple sclerosis, narcolepsy, and systemic sclerosis among various other disease phenotypes. This evidence concerns the gene HLA-DQA2 and narcolepsy.