KYNU and CCBL1 are enzymes of the kynurenine pathway that have multiple biological implications, such as an active role in the immune response; some kynurenins are neuroactive and the kynurenine pathway is involved in many diseases such as Alzheimer's disease, amyotrophic lateral sclerosis, Huntington's disease, AIDS dementia complex, malaria, cancer, depression, and schizophrenia, where imbalances in tryptophan and kynurenines have been found.40 The gene discussed is KYAT1; the disease is depressive disorder.