In the exceedingly rare congenital erythropoietic porphyria (uroporphyrinogen III synthetase deficiency), the stools and urine turn dark red (porphyrinuria
) and bones and teeth acquire a yellow-orange color.
Pathological causes are hematuria, hemoglobinuria, myoglobinuria, and porphyrinuria
. Erythrocytes impart a red color to urine, which turns brown within hours due to oxidation of hemoglobin to methemoglobin, particularly at acidic pH.
The role of nicotinic acid in the prevention of pellagra, roentgen sickness and increased porphyrinuria
. I Clin Invest.
The GABA shunt pathway also generates succinyl CoA and glycine which are substrates for porphyrin synthesis contributing to porphyrinuria
. Since glycine is utilized for porphyrin synthesis it is not available for cystathionine synthesis.
An investigation of porphyrinuria
in Australian children with autism.
A causal relationship between heavy metal inhibition and porphyrinuria
was demonstrated both in rats and humans exposed to Hg.