Principles of Biochemistry, Volume 2 - A. Lehninger 1985

Bioenergetics and Metabolism
Biosynthesis of Amino Acids and Nucleotides
Certain genetic disorders lead to the accumulation of porphyrin derivatives

Genetic defects affecting various Enzymes in the biosynthetic pathway from Glycine to Porphyrins lead to the accumulation of specific porphyrin precursors in erythrocytes, Body Fluids, and the Liver. These pathological conditions are known as the Porphyrias. One type of porphyria, which primarily affects erythrocytes, is characterized by the accumulation of uroporphyrinogen I, an abnormal isomer of a protoporphyrin precursor. This condition results in red urine, strong fluorescence of the Teeth under ultraviolet light, and heightened photosensitivity of the Skin.

Another type of porphyria involves the accumulation of the porphyrin precursor porphobilinogen in the liver, accompanied by neuropsychiatric disorders. King George III, who ruled England during the American War of Independence (1776–1781), is believed to have suffered from this form of porphyria. Medical historians suggest that the emotional instability characteristic of this disease accounted for the king's erratic behavior, as he stubbornly insisted on excessive taxation and harsh punishments for the American colonies.



Last update: 06/08/2026

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