Neopterin and biopterin are by-products of the redox reactions involving tetrahydrobiopterin (BH4). BH4 functions as a cofactor for the enzymes responsible for the production of monoamine neurotransmitters (ephinepherine, norepinephrine, DOPA, serotonin), and as a cofactor in nitric oxide production. Low biopterin levels may reflect insufficient BH4 status. Restricted BH4 cofactor availability has been suggested as an etiologic factor in:
Neopterin is a marker of inflammation, allowing detection and monitoring of inflammatory processes. The origin of the inflammation may be the small intestine pathology that so often requires treatment in children with Autism Spectrum Disorders.
Neopterin is elevated in: