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خرید پکیج
تعداد آیتم قابل مشاهده باقیمانده : 3 مورد
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Diagnostic testing for active porphyrias

Diagnostic testing for active porphyrias
Concurrent or recent clinical manifestations Initial testing Additional testing (if initial results are positive) Types of porphyria identified Enzyme and DNA tests
Acute neurovisceral Spot urine PBG and total porphyrins (normalized with urine creatinine)

Spot urine ALA, PBG, and total porphyrins (quantitative, normalized with urine creatinine)

Plasma porphyrins*

Erythrocyte porphyrins

Fecal porphyrins
Delta-aminolevulinic acid dehydratase porphyria (ADP)

Erythrocyte ALAD

Sequence ALAD gene
Acute intermittent porphyria (AIP)

Erythrocyte PBGD

Sequence PBGD gene
Hereditary coproporphyria (HCP) Sequence CPOX gene
Variegate porphyria (VP) Sequence PPOX gene
Blistering photosensitivity Total porphyrins (plasma*, serum, or spot urine), with fractionation if elevated

Erythrocyte total porphyrins

Urinary ALA and PBG

Fecal total porphyrins

Porphyria cutanea tarda (PCT)

Erythrocyte UROD

Sequence UROD geneΔ
Hepatoerythropoietic porphyria (HEP)

Erythrocyte UROD

Sequence UROD gene
HCP Sequence CPOX gene
VP Sequence PPOX gene
Congenital erythropoietic porphyria (CEP)

Erythrocyte UROS

Sequence UROS gene
Nonblistering photosensitivity Total erythrocyte porphyrins Erythrocyte metal-free and zinc protoporphyrin; plasma total porphyrins and fluorescence scan Erythropoietic protoporphyria (EPP) Sequence FECH gene
X-linked protoporphyria (XLP) Sequence ALAS2 gene
First-line testing for symptomatic patients is guided by clinical features (ie, neurovisceral, cutaneous chronic blistering, or cutaneous acute nonblistering). All spot urine measurements should be normalized with spot urine creatinine. If initial testing is positive, further comprehensive testing follows to identify the type of acute porphyria. Enzyme measurements may be used but are not available for all porphyrias. DNA testing usually follows establishment of a biochemical diagnosis. Refer to UpToDate topics on overview of porphyria and specific porphyrias for additional details and testing in asymptomatic patients.
PBG: porphobilinogen; ALA: delta-aminolevulinic acid; ADP: delta-aminolevulinic acid dehydratase porphyria; ALAD: delta-aminolevulinic acid dehydratase; PBGD: porphobilinogen deaminase; CPOX: coproporphyrinogen oxidase; PPOX: protoporphyrin oxidase; UROD: uroporphyrinogen decarboxylase; UROS: uroporphyrinogen III synthase; FECH: ferrochelatase; ALAS2: delta-aminolevulinate synthase-2.
* Plasma porphyrins should include measurement of the total, fractionation if the total is elevated, and determination of the fluorescence peak wavelength at neutral pH.
¶ It is important to verify that the method used by the laboratory measures all erythrocyte porphyrins and not just zinc protoporphyrin.
Δ UROD mutations are neither required nor specific for a diagnosis of PCT. UROD mutations are found in approximately 20% of patients with PCT and therefore are helpful if present. The presence of a UROD mutation is a predisposing factor but not sufficient to cause PCT.
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