Variegate porphyria (VP). Protoporphyrinogen oxidase (PROTO) deficiency.
Incidence
AD disease. It occur in heterozygous affecyed pts. Enzyme is deficient by 50%. Frequent in South Africa's whites, where incidence is 300/100.000, but it occurs everyplace.
Clinical Characteristics
The clinical symptoms are similar to Acute Intermittent Porphyria. Cutaneous traumasensitivity and photosensitivity is typical and prominent as well as the polyneuropathy.
Precipitants
Barbiturates, antiepileptic drugs, sulfas, ergotamine, chloroquine and other drugs may trigger an attack. Skin trauma and light is very important in producing skin lesions.
Provocation Tests
Not recommended.
Diagnostic Procedures
EB-F, EB-W (usually not available). There is excessive excretion of coproporphyrin in urine. Also there is high levels of ALA and PBG in urine during attacks. Fecal coproporphyrins are normal.