What's porphyria?
Porphyrias are inborn errors of metabolism. They are characterized by the increase or elevation of Amino Levulinic Acid or Porphyrins. (Look down for a brief pathway of Heme synthesis).
There are many types of porphyrias but I will explain just what King George III had.
He had what is called Acute Intermittent Porphyria.
It is an inherited condition with the enzyme Uroporphyrinogen - 1 - synthase (Porphobilinogen deaminase) deficient.
Since PBG deaminase catalyses the conversion of Porphobilinogen to Hydroxymethylbilane, there's an increase in porphobilinogen and a secondary increase of ALA synthase's (Amino Levulinic Acid) activity and hence ALA and PBG increases in quantity.
Now, when ALA and PBG both increase they tend to be elevated in the urine too but they're colourless so it doesn't show in the urine UNTIL it is left to be oxidized and it turns into a coloured urine.
ALA and PBG elevation can cause neuropsychiatric symptoms whilst increase in porphyrins can cause cutaneous photosensitivity.
In AIP, ALA and PBG is elevated and it explains the bouts of madness presented by King George III. Although the rest of the symptoms are quite different in their manifestations.
LOL this is soo cool man, u even put in the heme synthesis chart hehe, its a good way of puttin stuff into memory, the corelation i mean hehe
ReplyDeleteYea, thanks :) I'm gonna do that for a lot of diseases so that I remember them :P
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