Porphyria

Porphyria is the umbrella term for a group of rare conditions that involve a molecule called ‘heme’ or ‘haem’. Heme contains iron and is used in metabolic processes throughout the body. Porphyria occurs when the body cannot convert compounds called ‘porphyrins’ into heme.

While all tissues have heme, those that use it the most are the red blood cells, liver and bone marrow. Porphyria can affect the skin, nervous system and gastrointestinal system.

More women than men are affected by porphyria

In most cases, a combination of genetic and environmental factors trigger porphyria symptoms. There is no cure for porphyria, but by avoiding triggers, development of symptoms of porphyria can be prevented.

Treatments are available to manage the symptoms

Symptoms vary from one type of porphyria to the next. Cases are generally classified into one of three groups, which include: – this condition mostly affects the nervous system.

The skin is occasionally affected

Acute porphyrias generally occur during adulthood and are rare before puberty or after menopause. Different types of acute porphyria include ‘acute intermittent porphyria’ and ‘erythropoietic protoporphyria’. Symptoms of acute porphyrias may include: – this condition affects the skin but not the nervous system.

The skin is highly sensitive to sunlight and exposure tends to trigger symptoms within minutes.

Cutaneous porphyrias may develop during childhood

Different types of cutaneous porphyria include ‘porphyria cutanea tarda’ and ‘hepatoerythropoietic porphyria’. Symptoms may include:

• – this condition affects both the skin
• the nervous system

Sunlight exposure tends to rapidly trigger symptoms

Different types of neurocutaneous porphyria include ‘variegate porphyria’ and ‘hereditary coproporphyria’. The substance heme (or haem) is used in various metabolic processes. The body makes heme from porphyrins, which are metallic compounds found naturally in the tissues of animals and plants.

The conversion of porphyrins into heme requires the action of special proteins called enzymes.

Genes control the action of enzymes

An altered gene (or genes) can stop the body from making one or more of these enzymes. This creates a lack of heme and a build-up of porphyrins, which causes the signs and symptoms of porphyria.

Most forms of porphyria are inherited

This means the genetic predisposition for the condition is passed from one generation to the next. The altered gene interferes with the body’s ability to create one or more enzymes needed to turn porphyrins into heme. The pattern of inheritance may include: – the altered gene is inherited from one parent.

This altered gene overrides the healthy gene inherited from the other parent – the altered gene is inherited from both parents. Not everyone who has the altered gene will develop porphyria. It appears that an environmental trigger is needed for porphyria to develop.

Triggers and responses vary between individuals

All triggers for porphyria involve increased heme production

Common triggers include:

• prescription drugs such as barbiturates tranquillisers sedatives
• oral contraceptives
• some types of antibiotics fasting. Be guided by your doctor
• but general suggestions for preventing symptoms of porphyria include
• In all cases avoid known triggers – for example
• don’t smoke or drink alcohol

When out in the sun, wear sunglasses, a brimmed hat, a long-sleeved top and long pants.

Apply SPF 30+ sunscreen to exposed skin areas.

Protect your skin every day

For example, wear rubber gloves when handling chemicals or very hot water.

Avoid perfumed soaps

Regularly apply barrier cream to the hands

Eat regular meals

Consider wearing a medical alert bracelet or pendant, as surgery and some medications can provoke symptoms. As porphyria is rare, most doctors are unfamiliar with it and may not recognise the symptoms. Porphyria mimics the symptoms and signs of other medical conditions such as Guillain-Barre syndrome, eczema, multiple sclerosis and irritable bowel syndrome.

This can delay diagnosis

Diagnostic tests for porphyria may include:

• genetic testing. Without medical treatment complications of porphyria may include liver problems
• which may require a liver transplant in severe cases. Treatment for acute porphyria may include
• addressing the underlying cause – for example
• prescribing antibiotics to treat an infection or ceasing a particular medication admission to hospital in severe cases

Treatment for cutaneous porphyria may include:

• or if it runs in your family
• it may be helpful to speak to a genetic counsellor

Genetic counsellors are health professionals qualified in both counselling and genetics. As well as providing emotional support, they can help you to understand porphyria and what causes it, how it is inherited, and what a diagnosis means for your child’s health and development, and for your family. Genetic counsellors are trained to provide information and support that is sensitive to your family circumstances, culture and beliefs.

If porphyria runs in your family, a genetic counsellor can explain what genetic testing options are available to you and other family members. You may choose to visit a genetic counsellor if you are planning a family – to find out your risk of passing the condition on to your child, or to arrange for prenatal tests. (GSNV) is connected with a wide range of support groups throughout Michigan and United States and can connect you with other individuals and families affected by porphyria.

Symptoms of porphyria acute porphyrias muscle pain or paralysis seizures disorientation hallucination bloody (red) urine hypertension gastrointestinal problems such as vomiting, abdominal pain and constipation cutaneous porphyrias red, itchy, blistered, painful and swollen skin bloody (red) urine neurocutaneous porphyrias What causes porphyria Porphyria is usually inherited autosomal dominant inheritance autosomal recessive inheritance Porphyria needs an environmental trigger female sex hormones that arise at puberty artificial hormones such as those used in common female contraceptives sunlight alcohol cigarette smoking infection surgery Prevention of porphyria symptoms Diagnosis of porphyria physical examination medical history urine tests to check for elevated substances including porphyrins blood tests to check for high levels of porphyrins in the plasma stool sample to check for excreted porphyrins Common complications of porphyria permanent hair loss skin scarring permanent skin pigmentation changes dehydration breathing problems high blood pressure (hypertension) low salt levels in the blood (hyponatremia) kidney failure Treatment – acute porphyria pain medication medication called ‘hematin’, which is a type of heme the body can use intravenous fluids and glucose Treatment – cutaneous porphyria oral administration of activated charcoal, which helps to absorb excess porphyrins Genetic counselling and porphyria The Genetic Support Network of Michigan Where to get help In an emergency, call 911 for an ambulance Your GP (doctor) NURSE-ON-CALL (616) 555-0024 – for expert health information and advice (24 hours, 7 days) Porphyria Association 0413 757 892 Genetic Support Network of Michigan (616) 555-0200 Genetic Alliance United States (616) 555-0100 Michigann Clinical Genetics Services (616) 555-0400.

Key Points

• In most cases, a combination of genetic and environmental factors trigger porphyria symptoms
• There is no cure for porphyria, but by avoiding triggers, development of symptoms of porphyria can be prevented
• Treatments are available to manage the symptoms
• Symptoms vary from one type of porphyria to the next
• Symptoms of acute porphyrias may include: – this condition affects the skin but not the nervous system