Mutation Report
Journal of Investigative Dermatology (2001) 116, 610–613; doi:10.1046/j.1523-1747.2001.01293.x
Homozygous Variegate Porphyria: 20 y Follow-Up and Characterization of Molecular Defect
Raili Kauppinen, Kaisa Timonen*, Mikael von, und zu Fraunberg, Eila Laitinen†, Helena Ahola, Raimo Tenhunen†, Shigeru Taketani‡ and Pertti Mustajoki
- Department of Medicine, Division of Diabetology, Finland
- *Department of Medicine, Division of Dermatology, Finland
- †Clinical Chemistry of the University of Helsinki, Finland;
- ‡Department of Biotechnology, Kyoto Institute of Technology, Kyoto, Japan
Correspondence: Dr Raili Kauppinen, Department of Medicine, University Central Hospital of Helsinki, Haartmaninkatu 4, FIN-00029 HUS, Helsinki, Finland. Email: raili.kauppinen@hus.fi
Received 11 April 2000; Revised 27 November 2000; Accepted 1 December 2000.
Abstract
The long-term follow-up of a homozygous variegate porphyria patient revealed severe photosensitivity accompanied by mild sensory neuropathy and IgA nephropathy. A 35T to C transition in exon 2 (I12T) and a 767C to G transversion in exon 7 (P256R) of the protoporphyrinogen oxidase gene were identified from both alleles of the patient's cDNA and genomic DNA samples. Both prokaryotic and eukaryotic expression studies showed that the first mutation in the evolutionary conserved region resulted in a decrease in the protoporphyrinogen oxidase activity in contrast to the polymorphic substitution in exon 7, which affected the function of the enzyme assayed in Escherichia coli but not COS-1 cells.
Keywords:
mutation, porphyria, protoporphyrinogen oxidase, variegate porphyria
Abbreviations:
PPOX, protoporphyrinogen oxidase; VP, variegate porphyria
