What is Porphyria? & Acquired Porphyria
Porphyrias are a group of 8 different diseases of heme synthesis in which over production of porhyrin compounds results from deficient enzyme activity in the biosthentic pathway of heme, either in the liver or red blood cells in the bone marrow. In the final steps of this process, iron is added in the red blood cells, producing heme, which is then made into hemoglobin within the red blood cell.
Most of the porphyrias are related to liver disease; one form involves both the liver and bone marrow, and another form originates in the red blood cells. Red blood cells live for about 3 months.
When they die they break down to bilirubin which is processed by the liver. So the process of producing new red blood cells to replace the older ones is continuous. The biochemistry of the porphyrias is very complicated, but the important thing to note is that it may be caused by a series of deficient enzymes which may result in an overproduction and over accumulation of one or more of the porphrins. These porphyrins may be deposited in various tissues where they are quite toxic and thus cause symptoms.
The classifications of porphyria is as follows :
A. Congenital erythropoietic porphyrias (very rare)
B. Hepatic porphyria (liver)
1.Genetic forms
a) Acute intermittent porphyria
b) Hereditary coproporphyria
c) Variegate porphyria. (In 1620 2 Dutch settlers in South Africa married and today 10,000 of their descendants are affected)
2.*** Acquired and secondary porphyria****
Erythrohepatic protopotphyria (liver and red blood cells)
The Acquired porphyrias may be considered to be the result of an environmental insult or poison on either (1) a genetically predisposed individual or (2) a previously normal individual with no familial history or predisposition to the disease.
This means there has been damage to the liver or bone marrow or both, resulting in various deficiencies of different enzymes in the porphyrin-to heme-pathway, with the subsequent depositing of porphyrins in different tissues causing the disease.