Tetrahydrobiopterin

Tetrahydrobiopterin (BH4) is cofactor in the synthesis of the neurotransmitters dopamine, norepinephrine, epinephrine and melatonin. It is also a cofactor in the synthesis of nitric oxide.

MTHFR mutations

MTHFR A1298C is involved in converting 5-methylfolate (5MTHF) to tetrahydrofolate (THF), a reaction that produces one molecule of BH4. Mutations in this gene down regulate the methylation cycle and consequently, the production of BH4.

ME/CFS

BH4 was found to be raised in a pilot study of ME/CFS patients with orthostatic intolerance by Gottschalk and colleagues in 2023.

Notable studies

• 2024, Dysregulation of tetrahydrobiopterin metabolism in myalgic encephalomyelitis/chronic fatigue syndrome by pentose phosphate pathway - (Full text)
• 2023, Detection of Elevated Level of Tetrahydrobiopterin in Serum Samples of ME/CFS Patients with Orthostatic Intolerance: A Pilot Study - (Full text)

A substance that acts with another substance to bring about certain effects. In biochemistry, a cofactor is a molecule that is necessary for a given biochemical reaction, but is not an enzyme or substrate of the reaction.

cofactor A substance that acts with another substance to bring about certain effects. In biochemistry, a cofactor is a molecule that is necessary for a given biochemical reaction, but is not an enzyme or substrate of the reaction.

See myalgic encephalomyelitis.

See chronic fatigue syndrome.

serum The clear yellowish fluid that remains from blood plasma after clotting factors have been removed by clot formation. (Blood plasma is simply blood that has had its blood cells removed.)

orthostatic intolerance (OI) - The development of symptoms when standing upright, where symptoms are relieved upon reclining. Patients with orthostatic intolerance have trouble remaining upright for more than a few seconds or a few minutes, depending upon severity. In severe orthostatic intolerance, patients may not be able to sit upright in bed. Orthostatic intolerance is often a sign of dysautonomia. There are different types of orthostatic intolerance, including postural orthostatic tachycardia syndrome (POTS).