6.2.4 Congenital Erythropoietic Porphyria (CEP)
Grading & Level of Importance: C
Disturbance of the heme biosynthesis.
Very rare. Symptoms (light sensitivity) starting early in life (10 years); Incidence 0.1:100'000.
Chronic polyetiologic disturbance of the hem-(porphyrin) biosynthesis in the erythrocytes, leading to accumulation of photosensitive porphyrins in the skin and other organs.
Aetiology & Pathogenesis
Autosomal-recessive inherited mutation of the hem biosynthesis due to reduced activity of the enzyme uroporphyrinogen-III synthase, leading to accumulation of hydroxymethylbilane; accumulation of the hem-precursor uroporphyrinogen I in skin, bone, teeth and internal organs.
Signs & Symptoms
Extreme light hypersensitivity, starting at birth. Blister formation and disfigurement due to scarring mutilations by UV light (“wolf children”). Hypertrichosis and poikiloderma. Risk of carcinoma development on scars. Red fluorescence of urine and red teeth (erythrodonty).
Light exposed areas.
Prototype: porphyria cutanea tarda: sporadic, genetic/familiar, toxic.
Congenital erythropoetic porphyria (Günther).
Laboratory & other workups
Determination of the defective enzymes and of uroporphyrinogen I in the urine (special laboratory).
Subepidermal blisters; scar tissue.
Acute with chronic sequelae.
Typical clinical features; confirmation by laboratory tests.
Other photodermatoses. Porphyria cutanea tarda and other blistering dermatoses.
Prevention & Therapy
Topical: Light protection (SPF/LSF > 30). Cave: Vitamin D-deficency due to lack of vitamin-D production in the skin by UV.
To be discussed: gene-therapy; allogeneic stem cell transplantation.
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