Protoporphyrinogen oxidase (PPO) converts protoporphyrinogen IX to protoporphyrin IX. A patient with Variegate Porphyria (VP) has a defect in this enzyme.
Inheritance: autosomal dominant
Genetic locus: 1q22
(1) bullae and skin fragility
(2) neurovisceral signs and symptoms
(3) acute attacks can occur
(4) positive family history
Laboratory findings (more pronounced during an acute attack):
(1) porphobilinogen and aminolevulinic acid are increased in the urine with greater amounts of porphobilinogen
(2) coproporphyrinogen III is increased in the urine
(3) protoporphyrinogen IX is increased in feces with lesser amounts of coproporphyrinogen III and porphyrin X
(4) erythrocytes do not show an increase in porphyrins
(5) presence of a mutation in protoporphyrinogen oxidase
Note that there are many overlapping features with hereditary coproporphyria (HCP). The distinction depends on fecal porphyrins and enzyme analysis.
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Specialty: Endocrinology, Clinical Laboratory, Gastroenterology