Congenital Erythropoietic Porphyria (CEP)

Synonyms

Disturbance of the heme biosynthesis.

Epidemiology

Very rare. Symptoms (light sensitivity) starting early in life (10 years); Incidence 0.1:100'000.

Definition

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).

Localisation

Light exposed areas.

Classification

Hepatic porphyrias

Prototype: porphyria cutanea tarda: sporadic, genetic/familiar, toxic.

Erythropoietic porphyrias

Erythropoetic prtoporphyria.
Congenital erythropoetic porphyria (Günther).

Laboratory & other workups

Determination of the defective enzymes and of uroporphyrinogen I in the urine (special laboratory).

Dermatopathology

Subepidermal blisters; scar tissue.

Course

Acute with chronic sequelae.

Complications

Mutilations; scars.

Diagnosis

Typical clinical features; confirmation by laboratory tests.

Differential diagnosis

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.

6.2.4 Congenital Erythropoietic Porphyria (CEP)