Adrenaline Creation Pathway

Adrenaline (A.K.A epinephrine) is produced from noradrenaline (norepinephrine), which is produced from Dopamine, which is produced from L-Dopa, which is produced from Tyrosine, which is produced from Phenylalanine (an amino acid) through the catalyst tetrahydrobiopterin (“BH4”). Note that BH4 is a quirky catalyst because it temporarily consumes its co-factor rather than catalyst.

Fault in Adrenaline Creation Pathway – PKU (Phenylketonuria)

Each stage and many additional ones involved in the initial production and recycling of BH4 – after its been oxidized to BH2 when creating tyrosine – requires a specific enzyme to do the job. Any genetic problems in any of these enzymes usually causes severe and immediately apparent conditions in babies, the most common being “PKU”.

Patients with PKU usually have a faulty phenylalanine hydroxylase enzyme which converts BH4 + phenylalanine into tyrosine. Unmanaged patients have extremely high levels of phenylalanine in the blood (as they can’t get rid of it) and tyrosine deficiencies. Untreated, mental deficiency is inevitable. Treatment for ~20% of patients involves BH4 supplementation via “Kuvan” (an artificial form of BH4 as natural BH4 can’t cross the blood brain barrier) and a very low protien diet. The rest of PKU patients will live on a near 2g protien allowance diet, with the rest provided by engineered protien which doesn’t include phenylalanine.

Other enzyme disorders are much rarer and most are ~1/1,000,000 type rarity. Some cause PKU, some cause symptoms via dopamine / serotonin deficiency and others are just plain complicated. Most cause severe disability when not treated straight away, others do okay. Even rarer variants of the variants involve complicated adolescence or adult onset which involve lots of borderline “just enough” levels of these neurotransmitters which lapse into insufficiency.


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