Table 1

Distinguishing features of the acute hepatic porphyrias

Type of porphyriaEnzyme deficiencyGeneIncidence per million*Clinical presentationIncreased haem pathway metabolites
ALA dehydratase porphyriaALA dehydratase ALAD Exceptionally rare†Acute attacksUrine: ALA
Red cell: zinc protoporphyrin
Acute intermittent porphyriaHydroxymethylbilane synthase HMBS 0.13Acute attacksUrine: ALA, PBG, uro
Faeces: copro III:I ratio normal
Plasma: FEP at 615–622 nm
Hereditary coproporphyriaCoproporphyrinogen oxidase CPOX 0.02Acute attacks and/or bullae and skin fragilityUrine: ALA, PBG, copro III
Faeces: copro III:I ratio>1.5
Plasma: FEP at 615–622 nm
Variegate porphyriaProtoporphyrinogen oxidase PPOX 0.08Acute attacks and/or bullae and skin fragilityUrine: ALA, PBG, copro III
Faeces: copro III:I ratio>1.5, proto>copro
Plasma: FEP at 624–628 nm
  • *Symptomatic incidence in European population.16

  • †Only eight cases reported to date.3

  • ALA, aminolevulinic acid; ALAD, 5-aminolaevulinic acid dehydratase; copro, coproporphyrin; FEP, fluorescence emission peak; PBG, porphobilinogen; proto, protoporphyrin; uro, uroporphyrin.