Furthermore, recent results of untargeted metabolite and cytokine data showed that cognitive impairment in post-acute sequelae of COVID (PASC) was associated with KP activation most especially QUIN, 3-hydroxyanthranilic acid (3-HAA), and KYN (p < 0.001); no other variables related to cognitive impairment [16]. This evidence concerns the gene NPPA and Cognitive impairment.