Questions about porphyrias

[Estranged]

Q1: Why aren't there ringed sideroblasts in porphyrias? Ringed sideroblasts are produced when iron can not be incorporated into heme. So if heme production is defective shouldn't iron accumulate in the mitochondria?
Q2: Why doesn't severe iron deficiency cause porphyria symptoms? If there is severe iron deficiency protoporphyrin IX should build up right?

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[KVBane]

Most porphyrias dont have anemia, because the problems in porphyrin synthesis occur in non-erythroid tissues, most manifestations are due to accumulations of protoporphyrin in other tissues. Like skin in PCT, or the liver in AIP. Since these conditions rarely effect the RBCs you dont get sideroblasts (remember that enzyme expression can be tissue specific.) Also remember these are enzyme deficiencies, not enzyme absences so the normal physiologic processes are still active. Also iron doesn't accumulate anywhere it wants to, the body has a complex system of regulating it between macrophages, and the liver, and acute phase reactants like hepcidin.

Porphyria is accumulation of products in tissues. If the process works well early metabolites of the porphyrin process do not accumulate anywhere, so no symptoms of porphyria.

Sources: Uptodate and Wikipedia