Diagnosis of feline acute intermittent porphyria presenting with erythrodontia requires molecular analyses

Vet J. 2013 Dec;198(3):720-2. doi: 10.1016/j.tvjl.2013.10.008. Epub 2013 Oct 10.


Erythrodontia is the hallmark of human congenital erythropoietic porphyria (CEP), but is also a major phenotypic feature of acute intermittent porphyria (AIP) in cats. In this study, detailed biochemical and molecular analyses were performed on two unrelated cats with autosomal dominant AIP that presented with erythrodontia, yellow-brown urine and mild changes in erythrocytes. The cats had elevated concentrations of urinary 5-aminolevulinic acid and porphobilinogen, and half normal erythrocytic hydroxymethylbilane synthase (HMBS) activity. Two novel HMBS mutations were detected; one cat had a deletion (c.107_110delACAG) and one cat had a splicing alteration (c.826-1G>A), both leading to premature stop codons and truncated proteins (p.D36Vfs 6 and p.L276Efs 6, respectively). These studies highlight the importance of appropriate biochemical and molecular genetic analyses for the accurate diagnoses of porphyrias in cats and extend the molecular genetic heterogeneity of feline AIP. Thus, although erythrodontia is a classic sign of congenital erythropoietic porphyria in human beings, cats with erythrodontia may have acute intermittent porphyria, a hepatic porphyria.

Keywords: Acute intermittent porphyria; Anemia; Feline; HMBS; Hydroxymethylbilane synthase.

Publication types

  • Case Reports
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cat Diseases / diagnosis*
  • Cats
  • Female
  • Florida
  • Hydroxymethylbilane Synthase / genetics*
  • Hydroxymethylbilane Synthase / metabolism
  • Molecular Sequence Data
  • Mutation
  • Porphyria, Acute Intermittent / diagnosis
  • Porphyria, Acute Intermittent / veterinary*
  • Sequence Analysis, DNA / veterinary
  • Tennessee
  • Tooth Discoloration / diagnosis
  • Tooth Discoloration / veterinary*


  • Hydroxymethylbilane Synthase