In our study, a significantly higher QUIN/KYN ratio was also observed in migraine children, suggesting an increased conversion of KYN to QUINA, which is facilitated by some enzymes, such as kynurenine 3-monooxygenase (KMO), kynurenine lyase (KYNU), and 3-hydroxy anthranilate dioxygenase (HAOO). Here, KMO is linked to migraine disorder.