Types of Porphyria
What is porphyria?
Porphyria is a group of rare disorders that affect the skin (cutaneous porphyria) and nervous system (acute porphyria). It involves a buildup of natural chemicals called porphyrins in the body. Porphyrins are necessary for the production of heme, which is a part of hemoglobin. Hemoglobin carries oxygen to organs and tissues.
In order to convert porphyrins into heme, eight enzymes are needed. Without these enzymes, porphyrins build up in the body. This results in major issues, especially regarding the nervous system and skin.
Types of porphyria
Porphyria has two main types: acute and cutaneous. Acute porphyria has a rapid onset and presents mainly in the nervous system. Cutaneous porphyria has a slower start and impacts the skin. Within these two categories are eight subcategories.
Acute delta-aminolevulinate-dehydratase deficiency porphyria
A deficiency in the delta-aminolevulinate-dehydratase (ALAD) enzyme occurs when both parents pass the disorder down to their child. This type of porphyria only presents in the nervous system. Symptoms include nausea, vomiting, constipation, diarrhea, urinary retention, respiratory impairment, weakness and tingling in the extremities. Abdominal pain, seizures, and, in severe cases, psychosis can also occur. Symptoms tend to worsen with low caloric intake, increased stress, and alcohol use.
Acute intermittent porphyria
Acute intermittent porphyria is autosomal dominant, meaning that only one parent carries the mutated gene. Symptoms include peripheral neuropathy, abdominal pain, nausea, vomiting, and seizures. Treatment involves IV infusions of heme. It can worsen with low caloric intake, alcohol use, reproductive hormone changes, infections, and the use of high-risk porphyrinogenic drugs.
Hereditary coproporphyria can be acquired autosomal recessive or autosomal dominant. It affects the nervous system and skin. Symptoms may include abdominal pain, psychiatric symptoms, peripheral neuropathies, constipation, nausea, and vomiting. Blisters and excessive hair growth may occur, as well as damaged skin in areas exposed to the sun. Pain usually lasts several days. Fasting and certain medications can cause onsets.
Variegate porphyria manifests in the nervous system and skin. Only one parent has to pass the gene for it to occur. An estimated 60% of individuals with this mutated gene are asymptomatic; however, photosensitivity may occur. Symptoms typically involve abdominal pain that may spread to the back, chest, arms and legs. Hypertension, constipation, nausea, vomiting, tachycardia, agitation and anxiety may also occur. A small percentage may experience neurological symptoms. Attacks are often associated with new medications.
Congenital erythropoietic porphyria
Congenital erythropoietic porphyria ensues when both parents pass on a genetic mutation to the child. It is present from birth. Symptoms include blisters, scarring, and erosion of skin that is exposed to light, reddish-colored urine, and hemolytic anemia. It may also cause damage to the bones and cartilage. Teeth may be stained white, and pink stains may appear in a child’s diaper. Blindness can result from congenital erythropoietic porphyria.
Porphyria cutanea tarda
There are three types of porphyria cutanea tarda, which is the most common type of porphyria. The main symptom is photosensitivity. Type 1 accounts for approximately 80% of cases, in which the enzyme levels are normal, but their activity is decreased and confined to the liver. Type 2 is inherited from one parent and is typically triggered by environmental factors. Many carriers are asymptomatic. Type 3, similar to type 1, is characterized by normal UROD genes; however, it is observed in more than one family member, which suggests a genetic factor.
Hepatoerythropoietic porphyria manifests in infancy or childhood. Symptoms are similar to congenital erythropoietic porphyria, including blisters, increased hair growth, scarring, and reddish urine. It can be distinguished from congenital erythropoietic porphyria through high isocoproporphyrin levels in feces and decreased URO-decarboxylase activity in erythrocytes.
Erythropoietic porphyria results in protoporphyrins in the red blood cells. This accumulation can cause painful, acute episodes of photosensitivity, usually beginning in early childhood. Often, a child will experience pain and cry when exposed to bright sunlight. Symptoms include intense burning, itching, or tingling upon sun exposure, scarring of the face, pediatric gallstones, redness, and swelling. It may result in liver failure.