Homozygous variegate porphyria: 20 y follow-up and characterization of molecular defect.
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.
Kauppinen
R
R
Department of Medicine, Division of Diabetology, Dermatology and Clinical Chemistry of the University of Helsinki, Finland. raili.kauppinen@hus.fi
Timonen
K
K
von und zu Fraunberg
M
M
Laitinen
E
E
Ahola
H
H
Tenhunen
R
R
Taketani
S
S
Mustajoki
P
P
D001483:Base Sequence / Q000235:genetics; D005420:Flavoproteins; D005500:Follow-Up Studies; D014644:Genetic Variation; D006720:Homozygote; D006801:Humans; D008297:Male; D024101:Mitochondrial Proteins; D008969:Molecular Sequence Data; D010088:Oxidoreductases / Q000235:genetics; D044925:Oxidoreductases Acting on CH-CH Group Donors; D010375:Pedigree; D011164:Porphyrias / Q000235:genetics* / Q000473:pathology / Q000503:physiopathology; D050768:Protoporphyrinogen Oxidase
D005420:Flavoproteins; D024101:Mitochondrial Proteins; D010088:Oxidoreductases; D044925:Oxidoreductases Acting on CH-CH Group Donors; C493978:PPOX protein, human; D050768:Protoporphyrinogen Oxidase