Congenital erythropoietic porphyria

An enzyme is a protein that helps convert one chemical substance into   another. In CEP, there is a shortage of one particular enzyme (uroporphyrinogen III synthase), which leads to the build up of a chemical (porphyrinogen) in the red blood cells. This abnormal substance reacts with sunlight and sets off a chemical reaction that can damage skin and other surrounding tissue. The light that porphyrinogen absorbs is different from that which causes ordinary sunburn. It can be caused by both visible and ultraviolet light.

Is congenital erythropoietic porphyria hereditary?

Yes. The parents of someone with CEP who have no symptoms of the condition are called carriers.  Each of them has a mutation in one of their two CEP genes. There is a 1 in 4 risk that each child born to 2 carriers will inherit the abnormal gene from both parents and thus develop the condition. This form of inheritance is called autosomal recessive.

What are the symptoms of congenital erythropoietic porphyria?

Individuals with CEP may not have all of the problems described in this leaflet as the severity of the condition varies. Usually, the condition presents with symptoms or signs soon after birth or in early childhood, but sometimes the onset of symptoms is not until the teenage years or early adulthood.

• Red urine is usually the first sign noticed in newborn babies with CEP. The intensity of the redness can vary from day to day.
• The teeth have a reddish/brown discoloration.
• The skin is very sensitive to light, especially direct sunlight, it may cause blisters or ulcers, which heal and leave scars. This most commonly happens where the skin is exposed to the sun, for example the backs of the hands, the face, ears and nose. The eyes may also be sensitive to bright sunlight or artificial light that can cause ulcers and scarring. Some patients may eventually lose their eyelashes, making their eyes easily irritated by small particles of dust and fibre.
• Increased fragility of sun-exposed skin can lead to scarring and disfigurement on affected skin such as the face, (ears, nose, mouth)and the hands.
• The skin may take longer to heal after injury or blistering and become infected.
• Anaemia, which varies in severity, is common in CEP. Anaemia develops because porphyrin damages red blood cells leading to tiredness, shortness of breath following minimal exertion and skin pallor.
• The spleen, which normally removes damaged red blood cells, can gradually enlarge and cause worsening of the anaemia and a reduction in the number of platelets (the blood cells that help to form blood clots to stop bleeding) and white cells in the blood (the blood cells that fight infections). This can lead to an increased risk of bleeding (such as repeated nose bleeds) and infections.
• CEP can occasionally cause thinning of the bones (osteoporosis), which can lead to bone fractures following minor injury.

• Repeated blisters and ulcers can cause extensive scarring in sun-exposed skin and permanent bald patches on the scalp.
• Some individuals may develop darkening of skin that is exposed to the sun.
• Excess body hair may develop, especially on the face and backs of the hands.

CEP may be suspected in children (or rarely in adults) who present with the problems described in this leaflet. The diagnosis is confirmed by measuring porphyrin levels in the blood, urine and faeces. These samples need to be protected from light until tested. A blood sample may also be taken to look for changes in the genes.

Testing for CEP in pregnancy is not routinely offered. However, CEP can be diagnosed in pregnancy in families where there is already a child with CEP. In this situation, cells taken from the fluid surrounding the baby in the womb (amniocentesis) or from the placenta, at 3 to 4 months into the pregnancy, are checked for the gene mutations causing CEP.

Can CEP be cured?

Currently, the only available cure for CEP is a bone marrow transplant (BMT) This involves transplanting healthy bone marrow from another person (the donor) to the person with CEP (the recipient). Following successful BMT, the symptoms of CEP such as photosensitivity and anaemia will improve. However, the scarring from previous damage to the skin is permanent.

For BMT to succeed, the bone marrow of the donor needs to be a good match with the recipient. BMT is a high-risk procedure, and is currently reserved for those severely-affected individuals who have a bone marrow donor who is a close match.

Bone marrow transplantation can be effective but long-term results are unknown and the procedure can be complicated by life-threatening infections.

Research is underway to cure CEP with gene therapy. This would involve correcting the abnormal gene in the affected person. It is hoped that this research will make good progress over the next decade.

How can CEP be treated?

The treatment of CEP is aimed at preventing scarring of the skin and eyes, and reducing the complications. Strict avoidance of sun exposure is vital for these patients.  Some or all of the following measures may be needed:

CEP is not made worse by any medications. Therefore, unless the person is allergic or intolerant to a medication, individuals with CEP have no restrictions in taking any form of medication.

Image courtesy of the British Journal of Dermatology (Br J Dermatol 2012; 167: 907).