What Are Porphyria and Gunther's Disease?

Porphyria includes Gunther's disease and at least seven other conditions

Porphyria: The Vampire Disease. Credit: www.bydewey.com

Porphyria refers to at least eight distinct conditions that are caused by a buildup of the chemical porphyrin. People with porphyria do not have enough of the enzymes that make heme, a substance which is found in bone marrow, red blood cells, and liver. This enzyme deficiency allows porphyrins, which are normally produced throughout the body, to accumulate in toxic amounts.

Porphyrias are typically divided into two categories –– acute and non-acute.

These conditions usually affect the nervous system or the skin. Each condition has its own set of symptoms and treatments. Acute porphyrias produce attacks of pain and neurological effects which are severe and appear rapidly. Acute types include acute intermittent porphyria, ALAD-deficiency porphyria, variegate porphyria, and hereditary coproporphyria. The non-acute types are porphyria cutanea tarda, hepatoerythopoietic, and congenital erythropoietic porphyrias.

Porphyrias are rare diseases. Together, they affect less than 200,000 people in the United States.

Acute Intermittent Porphyria

Acute intermittent porphyria (AIP) is the most severe kind of porphyria, with attacks developing over several hours or several days. Most individuals who inherit the gene for AIP never develop symptoms. Certain drugs are known to bring on or worsen attacks, as well as drinking alcohol, dieting, and hormonal changes.

An attack often includes severe abdominal pain and constipation, and may include nausea, vomiting, pain in the back, arms, and legs, muscle weakness, and even rapid heartbeat, confusion, and seizures.

Many times the first AIP attack may be misdiagnosed, and the medications given may make things worse for the patient.

Treatment should include a high-calorie diet, although why this helps relieve an attack scientists aren't quite sure. Heme therapy can be administered intravenously. Symptoms usually resolve after an attack, but some patients develop nerve damage.

The other acute porphyrias have symptoms similar to AIP. ALAD-deficiency porphyria is extremely rare. In hereditary coproporphyria, skin photosensitivity may occur.

Porphyria Cutanea Tarda (PCT)

Porphyria cutanea tarda (PCT) is the most common of the porphyrias. PCT is acquired, meaning it develops in an individual due to outside factors. These factors may include iron, alcohol, hepatitis C virus, estrogens (like in birth control pills), and smoking –– all of which can cause an enzyme deficiency in the liver, leading to PCT.

When exposed to the sun, the skin blisters and the skin may thicken and darken. PCT is considered the most treatable porphyria. Once symptoms start to show, removing one pint of blood from the patient every one to two weeks (up to 5 or 6 pints of blood total) removes iron from the liver and offers relief.

PCT usually does not recur after treatment.

Gunther's Disease

Congenital erythropoietic porphyria (CEP), also known as Gunther's disease, is extremely rare. Skin symptoms of Gunther's disease may be severe. Sun exposure may lead to blistering, scarring, and increased hair growth. Affected skin may harbor bacteria, and facial features and fingers may be lost through sun damage and infection. Hepatoerythropoietic porphyria is also very rare and causes skin blistering similar to that of Gunther's.

Erythropoietic Protoporphyria 

A disorder related to the porphyrias is erythropoietic protoporphyria (EPP). In EPP, protoporphyrin accumulates in the bone marrow, red blood cells, and the liver. Symptoms show on the skin after exposure to sunlight. These include swelling, burning, itching, and redness. Blistering and scarring are less common than they are with the other porphyrias.

Porphyria Genes Identified

Chromosome mapping has identified all the genes involved in the defective enzymes in the porphyrias. DNA testing can identify people who carry one of these defective genes. However, very few laboratories offer this type of testing. Prenatal diagnosis of congenital erythropoietic porphyria has been done, as well as successful gene therapy for both CEP and EPP. 

Information for this article was taken from:
- The American Porphyria Foundation (2015)
- Keung, Y-K, Chuahirun, T., & Cobos, E. (2000). Acute intermittent porphyria with seizure and paralysis in the puerperium. J Am Board Fam Pract, vol. 13, no. 1, 76-79.
- Lim, H. W.,& Cohen, J. L. (1999). The cutaneous porphyrias. Semin Cutan Med Surg, vol. 18, no. 4, 285-292.

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