Congenital erythropoietic porphyria

An enzyme is a protein that helps convert one chemical substance into another. In CEP, an important enzyme called ‘uroporphyrinogen III co-synthase’ does not work correctly in all cells. This leads to the build-up of porphyrins particularly in the red blood cells. When porphyrins react with sunlight, damage to the skin and surrounding tissues occurs.  

Is congenital erythropoietic porphyria hereditary?

Yes. People who carry the gene for CEP but have no symptoms are called carriers.  

Each carrier has a mutation in one of their two CEP genes. If both parents are carriers, there is a 1 in 4 chance that their children will inherit this gene mutation and develop CEP. This form of genetic inheritance is known as autosomal recessive. 

Around half of the people affected by CEP have a mild form of the condition. CEP can cause skin that: 

• blisters easily 
• is fragile  
• may cause scarring. 

However, this mild form does not affect the eyes or cause anaemia.  

The other half of affected people have the severe form. This causes their skin to be very sensitive to light (known as severe photosensitivity). Their skin blisters and is painful after daylight exposure. In the long term, severe scarring develops.  

Severe CEP also affects the eyes. It causes eye inflammation, scarring and sometimes visual impairment. A major problem caused by severe CEP is severe and long-term anaemia (a lower-than-normal level of haemoglobin in the blood. 

Symptoms usually start soon after birth or early childhood. In some people, symptoms do not appear until the teenage years or early adulthood. Common symptoms include: 

• Redish pink urine. This is often the first sign noticed in newborn babies. The colour can change from day to day.  
• Teeth that appear reddish-brown in colour. 
• Skin that is very sensitive to light, especially direct sunlight. Even a short time in sunlight can cause painful blisters or open sores (ulcers). These usually affect areas of skin exposed to the sun, such as the backs of the hands, the face, ears and nose. 
• Slow healing of blisters and ulcers or other injury. Repeated damage can leave permanent scars. 
• Damage to exposed areas of skin and to other tissues deeper tissue, such as bones and tendons. This can lead to infection, scarring and disfigurement. This can include the face and hands. 
• The eyes may also be sensitive to sunlight. In severe cases, long-term damage to the surface of the eye can cause scarring. and visual impairment. 
• Some people affected by the more severe type of CEP can develop anaemia (a lower-than-normal level of haemoglobin in the blood) This happens because porphyrins damage red blood cells. Severe anaemia may require regular blood transfusions in the long term. Over time, repeated blood transfusions can cause build-up of iron in the body, which may cause other health problems. Blood transfusions are given directly into a vein, to restore the body's levels of healthy red blood cells to treat severe anaemia 
• Bones can become thinner and weaker, a condition called osteoporosis, which can increase the risk of fractures after minor injuries. 
• Permanent patches of hair loss on the scalp may be experienced.  
• Some people may develop darkening of skin that is exposed to the sun. 
• Excess hair growth can occur, especially on the face and backs of the hands. 

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

The diagnosis is confirmed by measuring porphyrin levels in the blood, urine and faeces samples. These samples must be protected from light until testing is complete. A blood sample may also be taken to look for changes in the genes.  

During pregnancy, prenatal testing is available for high-risk families with a known mutation if they wish. It is usually performed at 3-4 months into the pregnancy via chorionic villus sampling (CVS) or amniocentesis. 

Can CEP be cured?

Severe CEP can be cured by bone marrow transplantation (BMT). This involves replacing the bone marrow. of the patient with bone marrow from a healthy person (the donor). 

Bone marrow is the soft, spongy, jelly-like tissue inside bones. It is where essential red blood cells, white blood cells, and platelets are produced.  

If BMT is successful, the bone marrow produces healthy blood cells. This can improve the symptoms of CEP, such as photosensitivity and anaemia. However, it cannot repair scarring caused by earlier skin or eye damage.  

For BMT to be successful, the bone marrow of the donor needs to be a close match with the patient. BMT can be effective, but it is a high-risk procedure and can lead to life-threatening complications. Because of this, it is usually considered for people who are severely affected by CEP and who have a suitable donor. 

Current research is focusing on gene therapy to potentially cure CEP. This approach aims to correct the faulty gene that causes CEP. Gene therapy for CEP is still being researched, and it is not yet widely available.  

How can CEP be treated?

The treatment of CEP aims to reduce damage to the skin and eyes and manage complications. It is very important to stay out of the sun as much as possible.  

Some or all of the following measures may be needed: 

Can medications make CEP worse?

No. CEP is not known to be made worse by medicines. 

This means that people affected by CEP do not usually need to avoid any specific medicines because of their condition. Medicines can be taken as normal, unless the person is allergic or intolerant to a particular medication. 

If you are unsure about any medications, you should discuss this with your healthcare professional.