Congenital Erythropoietic Porphyria
Erythropoietic porphyria (EP) is a rare inborn error of porphyrin-heme synthesis inherited that is as an autosomal recessive trait. Accumulation of certain porphyrins cause cutaneous photosensitivity characterized by blisters, erosions, and scarring of light-exposed skin. Chronic damage of skin, cartilage, and bones can cause mutilation. Hypertrichosis (abnormal hairyness), erythrodontia (pink stained teeth), and reddish-colored urine are often present. Hemolytic anemia can be mild or severe, with resultant splenomegaly and fragility of bones. The typical complaint is blistering and fragility of light-exposed skin in an individual with discolored urine. The presentation of erythropoietic porphyria at birth in a patient with a history of a difficult perinatal course and concomitant jaundice usually indicates severe disease. Patients may have a history of hemolytic anemia before the complete diagnosis is recognized. Even early prenatal cases have been reported.
Porphyrins are released from maturing erythrocytes into the plasma and are excreted by renal mechanisms. Urine with a port-wine color is produced. The interaction of excess porphyrins in the skin and light radiation causes photoxidative damage of biomolecular targets that is manifested as fragility and blistering and may result in severe scarring.
Erythropoietic porphyria is reported in diverse populations, but is extremely rare. The total number of cases reported worldwide is less than 200. Erythropoietic porphyria occurs in both males and females and all races with approximately equal frequencies.
The prognosis is not invariably poor. Most patients with erythropoietic porphyria survive into adulthood, with a life expectancy of 40-60 years. Erythropoietic porphyria typically occurs in infants or young children; however, several adult-onset cases have been reported.
Findings at physical examination may include:
- Photosensitivity, with formation of vesicles and bullae, early in the course of the disease
- Increased fragility and erosions can contribute to mutilation, especially on the face (eg, nose, mouth, ears) and hands.
- Hypertrichosis of the face and extremities is common.
- The teeth have a reddish color.
- The teeth fluoresce under a Wood light due to porphyrin deposition in the dentine and enamel.
- Pink staining of the diapers in the neonatal period is common; this staining is due to the porphyrin pigment in the urine.
- The eyelids may fluoresce under a Wood light.
- Corneal scarring may occur, with eventual blindness.
- Porphyrins are also deposited in the bone, where they cause an orange-red fluorescence.
- The severe loss of bone with subsequent contractures and deformities occurs in most adults with erythropoietic porphyria.
- X-ray studies show osteopenia and acro-osteolysis.