Definition

The term porphyria refers to a group of at least eight disorders that differ clinically from each other, but all share the same problem of accumulation of "porphyrins" or "porphyrin precursors" in the body. Porphyrin is a building block for heme. And heme is the iron-containing part of the hemoglobin in red blood cells that carries oxygen to all of the organs in our body.

The build up of the porphyrins in the body cause symptoms in two major organ systems: the nervous system and the skin.

• Effects on the nervous system occur in the acute porphyrias. The diagnosis is often delayed because the symptoms are nonspecific. Some patients have attacks in which the nerves of the body do not function properly. Abdominal pain [2] and weakness can be a symptom.
• Skin manifestations can include burning, blistering, and scarring of sun-exposed areas.

The terms "porphyrin" and "porphyria" are derived from the Greek word "porphyrus" meaning purple. Urine from some porphyria patients may be reddish in color due to the presence of excess porphyrins and related substances, and the urine may darken after standing in the light. Excess porphyrins are also excreted in the stool.

Some types of porphyria have onset in early childhood, some at puberty, and others during adulthood. The onset most frequently occurs between the ages of 20 and 40. The disease affects men less often than women, in whom attacks are related to the menstrual cycle. Long periods may separate attacks, which can be precipitated by drugs, infections, alcohol consumption, and dieting.

Causes

Most types of porphyrias are inherited. One subtype, porphyria cutanea tarda, is acquired. The porphyrias may be inherited as either autosomal dominant (caused by inheriting one abnormal copy of the gene) or autosomal recessive (requires inheritance of two abnormal genes) traits depending on which type of porphyria is involved.

Risk Factors

A risk factor is something that increases your chance of getting a disease or condition. The most common risk factor for porphyria is having a family member with this disease. Also, Caucasians are at greater risk than Blacks or Asians.

If you have porphyria, certain factors can increase your risk of a porphyria attack. These include: drugs, chemicals, alcohol, dieting, and sunlight. Triggers for specific types of porphyria are listed below:

Symptoms

Porphyria can cause skin or nervous system problems. Specific symptoms depend on the type.

Diagnosis

The doctor will ask about symptoms as well as medical [14] and family history. A physical examination will also be done.

Tests differ for the various types of porphyria, and may include blood, urine, and/or stool tests to check for excess porphyrin or to check for a specific enzyme deficiency. In some cases specific genetic testing may be available as well.

Treatment

For all types of porphyria, treatment includes the following:

• Avoiding known triggers and drugs that can precipitate an attack
• Eating a high-carbohydrate diet

Porphyria that affects the skin require special attention to protect the skin from injury and/or infection.

Specific treatment depends on the type of porphyria.

Treatment may include:

• Oral beta-carotene
• Oral charcoal, to aid excretion of porphyrins in stool
• Blood transfusions
• Spleen removal
• Bone marrow transplantation [17]

Prevention

Genetic testing may identify people at risk for porphyria. If there are people in your family with the diagnosis of porphyria, you may be eligible for testing if that family member has had genetic testing and that testing showed a change in the DNA; that change can then be looked for in you.

A genetic counselor can review your family history and risks for this disorder in you and your offspring and discuss appropriate testing that is available for you.

Although the genetic mutation cannot be corrected, attacks can be anticipated, prevented, or controlled. Steps to avoid porphyria attacks and complications include the following:

• Avoid drugs and other triggers
• Protect skin from injury or infection