23 Porphyrias

  • anything increases activity of P450 can exacerbate condition

  • anemia can result with severe inhibition of enzymes

Porphyria

  • two common ones are hepatic porphyria: heme synthesis affected in liver

PCT

  • some carboxyl groups have 3 carbons, others 2

  • A for acetic, P for propionic

  • Uroporphyrinogen III must be oxidized, lose H2, to be converted to uroporphyrin III

  • skin major symptoms (cutanea)

  • heptatitis from uroporphyrins accumulation in liver
  • in kidney: tea colored urine

  • iron overload like hemochromatosis

  • determine high porphyrin, then fractionate to determine high uroporphyrin

  • vampire hypothesis
  • consume heme/blood, inhibit heme synthesis

Acute Intermittent

  • late in pathway: skin symptoms
  • early in pathway: neurologic symptoms

  • low glucose, increased ALA synthase, rising heme

  • confusion, delirium, dementia

  • inhibited porphobilinogen deaminase and increased D ala synthase leads to increased D ala and porphobilinogen

  • urine darkens over time

  • avoid triggers