A FEW THOUGHTS ON PORPYRIA

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Sample Lab Tests

In acute hepatic Porphyria, the best screening tests are:
**urinary porphobilinogen (PBG)
**aminolevulinic acid (ALA).

When there are cutaneous symptoms that suggest Porphyria, the best screening test is a:
**plasma porphyrin assay.

If one of these screening tests is abnormal, more extensive testing, including urinary, fecal, and red blood cell porphyrins, are often indicated.

DNA testing to identify the specific mutation in an individual’s Porphyria-causing gene is also recommended. Before requesting DNA testing, it is helpful that patients have biochemical testing. However, many patients have not had an acute attack or are not symptomatic at present, so biochemical testing may be inconclusive.

In contrast, DNA testing is the most accurate and reliable method for determining if a person has a specific Porphyria and is considered the “gold standard” for the diagnosis of genetic disorders. If a mutation (or change) in the DNA sequence is found in a specific Porphyria-causing gene, the diagnosis of that Porphyria is confirmed. DNA analysis will detect more than 97% of disease-causing mutations. DNA testing can be performed whether the patient is symptomatic or not. Once a mutation has been identified, DNA analysis can then be performed on other family members to determine if they have inherited that Porphyria, thus allowing identification of individuals who can be counseled about appropriate management in order to avoid or minimize disease complications.

First-line Testing
It is important to know that the same screening test (i.e. first line test) is not suitable for all porphyrias. Therefore, testing must be tailored to the presenting symptoms and the type of porphyria suspected. Broadly speaking, the different porphyrias can be grouped into 3 categories when testing is being considered.

Table 1. First-line Testing is different for Acute Porphyrias, Blistering Cutaneous or Nonblistering Cutaneous Porphyria
Symptoms Test
Acute attacks of severe abdominal pain, nausea, vomiting, rapid heartbeat and other symptoms. Spot urine porphobilinogen (PBG) and total porphyrins*
Blistering skin photosensitivity (with or without acute attack symptoms) Plasma total porphyrins or urine total porphyrins
Nonblistering photosensitivity Erythrocyte total protoporphyrin – if elevated measure metal-free and zinc-protoporphyrin in the same sample
*Obtain sample when symptoms are present, if possible
Porphyrins, Qn, 24 Hr Ur. by Labcorp
Uroporphyrins (UP) 01 3 ug/L Undefined
Uroporph(UP),24hr 10 ug/24 hr 0-24
Heptacarboxyl (7-CP) 01 4 ug/L Undefined
Heptacarb(7-CP),24hr 13 High ug/24 hr 0-4
Hexacarboxyl (6-CP) 01 <1 ug/L Undefined
Hexacarb(6-CP),24hr <3 High ug/24 hr 0-1
Pentacarboxyl (5-CP) 01 1 ug/L Undefined
Pentacarb(5-CP),24hr 3 ug/24 hr 0-4
Coproporphyrin (CP) I 01 23 ug/L Undefined
Coproporph(CP)I,24hr 74 High ug/24 hr 0-24 HIGH
Coproporphyrin (CP) III 01 67 ug/L Undefined
Copropor(CP)III,24hr 214 High ug/24 hr 0-74 HIGH
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It is important to know that the same screening test (i.e. first line test) is not suitable for all porphyrias. Therefore, testing must be tailored to the presenting symptoms and the type of porphyria suspected. Broadly speaking, the different porphyrias can be grouped into 3 categories when testing is being considered.

First-line Testing for the Acute Porphyrias
Table 1. First-line Testing for Patients in Whom Acute Porphyria is Suspected
Symptoms Test Laboratories
Acute attacks of severe abdominal pain, nausea, vomiting, rapid heartbeat and other symptoms. Spot or 24 hour urine delta-aminolevulinic acid (ALA) and porphobilinogen (PBG)* UTMB, ARUP, Mount Sinai**, Mayo, Quest, LabCorp
Blistering skin photosensitivity (with or without acute attack symptoms) Plasma total porphyrins UTMB, ARUP, Mayo, Quest, LabCorp
*Take sample when symptoms are present

1) Acute Porphyrias
An acute porphyria should be suspected if patient presents with neurolvisceral signs and symptoms. The first-line screening test is measurement of urinary porphobilinogen (PBG). PBG is markedly increased in all patients during acute porphyria attacks and not markedly elevated in other medical conditions that can present with similar symptoms. Therefore, this test is both sensitive and specific for diagnosing an acute porphyria. An exception is ADP, in which ALA is elevated but not PBG. However, the condition is not usually under consideration because of its extreme rarity.
Measurement of PBG is often combined with ALA and total urine porphyrins. In some patients with acute porphyria, urinary porphyrins may remain increased longer than ALA and PBG. However, mild increases in urinary porphyrins can occur in other medical conditions and is therefore much less specific than increases in ALA and PBG. In urgent situations, a “stat” PBG for diagnosis is not available through any of the large reference labs. While the report is pending, initial management of the patient should be tailored to the possibility of acute porphyria, correcting fluid and electrolyte imbalances, pain control, and avoidance of medications that could worsen an attack (such as phenytoin for seizures). Patients with progressive neurological signs should be started on intravenous hemin. Intravenous dextrose can be administered while hemin is being prepared but should not cause a delay of hemin infusion.
If urine ALA and PBG are normal during an attack, it essentially rules out an acute porphyria. If urine ALA and PBG are markedly increased, a diagnosis of an acute porphyria is confirmed and further testing is needed to identify the type of acute porphyria. A minor (~2-fold) elevation in urine porphyrins (especially coproporphyrin) with normal ALA and PBG is nonspecific and may not require further testing.

Table 2. Second-line Biochemical Testing for Acute Porphyrias: Laboratory Findings to Differentiate Between AIP, HCP and VP.
Acute Porphyria HMBS activity in RBCs Urine PBG Urine ALA Urine porphyrins Fecal porphyrins Plasma porphyrins
AIP Decreased in ~90% of cases elevated elevated Markedly increased; mostly uroporphyrin Normal or slightly increased Normal or slightly increased
HCP Normal elevated elevated Markedly increased; mostly coproporphyrin Markedly increased; mostly coproporphyrin III Normal or slightly increased
VP Normal elevated elevated Markedly increased; mostly coproporphyrin III Markedly increased; mostly protoporphyrin Markedly increased; Fluorescence peak (at neutral pH) at ~626nm
ADP Normal normal elevated Markedly increased; mostly coproporphyrin III Normal or slightly increased Normal or slightly increased
Labs that can be used for second-line testing include: UTMB, ARUP, Mayo, Quest, and LabCorp

2) Cutaneous Porphyrias
The screening tests vary by specific symptoms for the cutaneous porphyrias. Total plasma porphyrins should be done for blistering skin photosensitivity. If this test is normal, cutaneous porphyrias that cause blistering skin lesions are effectively excluded. Further testing may be needed if total plasma porphyrins are increased. For suspected EPP/XLP, which has non-blistering photosensitivity, an erythrocyte protoporphyrin test is more specific. Urine ALA and PBG testing is not informative for any of the cutaneous porphyrias.

Porphyria Disorders (NGS Panel and Copy Number Analysis)
TEST: NGS396
Test number copied

CPT: 81479
PrintShare
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Genes Assessed
ALAD, C15ORF41, CPOX, FECH, HFE, HMBS, PPOX, SLC19A2, UROD, UROS
________________________________________Specimen Requirements
Blood: Draw blood in a lavender top EDTA tube, Sample Stability: 5-7 days, Preferred volume: 4 ml, Minimum volume: 2 ml, DO NOT FREEZE. Extracted DNA: From leukocytes, muscle, or fibroblasts: Preferred quantity: 1 microgram, Minimum quantity: 800 nanograms. Genomic DNA should be eluted in sterile Dnase/Rnase free water or TE. The A260:A280 ratio should be 1.8-2.0. Cultured Fibroblasts: Two T-25 flasks of fibroblasts, preferably ~90% confluent. TAT will be extended by 7-14 days if cells are not confluent upon arrival. Muscle: 50-75 milligrams muscle snap frozen in liquid nitrogen and maintained at -80°Celsius or below. Buccal Cells: One buccal swab should be used for collection. Do not discard solution in collection tube. Follow collection instructions supplied. Stability at ambient temperature is 60 days.
________________________________________
Container
Blood: Lavender-Top (EDTA) Tube, Buccal Swab from MNG Kit, Tissue or Extracted DNA: Sterile screw capped vial, Cultured cells: T25 flask
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________________________________________
Specimen
Blood | Extracted DNA | Cultured Fibroblasts | Muscle | Buccal Cells
________________________________________
Volume

SECOND LINE TESTING
Table 2. Second-line Biochemical Testing for Acute Porphyrias: Laboratory Findings to Differentiate the four Acute Porphyrias
Acute Porphyria HMBS activity in RBCs Urine PBG Urine ALA Urine porphyrins Fecal porphyrins Plasma porphyrins
AIP Decreased in ~90% of cases Variably elevated Variably elevated Increased; mostly uroporphyrin and coproporphyrin Normal or slightly increased Normal or slightly increased
HCP normal “” “” “” Markedly increased; mostly coproporphyrin III Normal or slightly increased
VP normal “” “” “” Markedly increased; mostly coproporphyrin III and protoporphyrin Markedly increased; Elevated, with fluorescence peak at ~626nm
ADP normal normal “” Increased; mostly coproporphyrin III Normal or slightly increased Normal or slightly increased
Labs that can be used for second-line testing include: UTMB, ARUP, Mayo, Quest, and LabCorp
Blistering Cutaneous Porphyrias (Images Below)

Total plasma or urine porphyrins are measured when porphyrias are considered as a possible cause of blistering skin photosensitivity. Normal results effectively exclude these cutaneous porphyrias. Further second line testing is needed if porphyrins are increased, because this finding is not specific, and porphyrinuria (especially coproporphyrinuria) is common in other diseases. If second line testing is negative, then porphyria is not present. If porphyria is present, the most likely possibility is PCT, which is the most common porphyria. But it is important to differentiate other porphyrias that can cause the same skin manifestations, and especially in adults are almost always initially misdiagnosed as PCT.
Table 3. Laboratory Findings to Differentiate PCT from other porphyrias that cause blistering skin lesions.
Porphyria Urine porphyrins Erythrocyte porphyrins Plasma Fecal porphyrins
PCT Elevated; mostly uro- and heptacarboxyl porphyrin Normal or slightly elevated Elevated, with fluorescence emission peak 615-620nm Normal or modest elevation with complex pattern including increased isocoproporphyrin
HEP “” Elevated, mostly zinc protoporphyrin “” Elevated with complex pattern including increased isocoproporphyrin
CEP Increased; mostly uroporphyrin I and coproporphyrin I Elevated, mostly uroporphyrin I and coproporphyrin I, or zinc proto porphyrin in milder cases “” Elevated, mostly coproporphyrin I
VP* Variable increases in ALA, PBG and porphyrins (usually mostly uroporphyrin and coproporphyrin Normal or slightly elevated Elevated, with fluorescence peak at ~626nm Elevated, mostly coproporphyrin III and protoporphyrin
HCP* “” “” Elevated, with fluorescence peak at 615-620 nm Elevated, mostly coproporphyrin III
*Elevation in plasma porphyrins with or without blistering skin lesions are common in VP, but uncommon in HCP in the absence of skin lesions.

Nonblistering cutaneous porphyrias
This type of photosensitivity is immediate and painful and leaves little if any blistering or other skin damage. It occurs only in the protoporphyrias, namely erythropoietic protoporphyria (EPP) and the less common X-linked protoporphyria (XLP). Urine ALA, PBG and porphyrins are normal in these conditions, because protoporphyrin is insoluble in water and excreted only in bile. It is essential to measure erythrocyte total protoporphyrin to screen for EPP and XLP, and to remember that urine testing is not informative. Plasma porphyrins are less elevated than in other cutaneous porphyrias, and may even be normal. Some major laboratories do not offer the proper testing for EPP and XLP. At present, only the UTMB Porphyria Lab and Mayo Medical Laboratories are recommended.
Table 4. Laboratory Findings in the protoporphyria (EPP and XLP).
Porphyria Urine porphyrins Erythrocyte total protoporphyrin Plasma porphyrins Fecal porphyrins
EPP Normal Subtantial elevation, >85% metal-free protoporphyrin Usually elevated, with fluorescence peak at ~634 nm, but may be normal Normal or modest elevation , mostly protoporphyrin
XLP “” Subtantial elevation, 50-85% metal-free protoporphyrin “” “”
Genetic testing
Confirmation of the diagnosis by genetic testing is recommended for all porphyrias. Importantly, knowing the familial mutation(s) enables screening of family members who may be at risk for developing symptoms or may pass a pathogenic mutation to the next generation. If the type of porphyria has been proven biochemically, it is usually necessary to examine (usually by sequencing) only one gene to identify the responsible mutation. Once the familial mutation is known, the testing of family members can be targeted to that mutation.

A Superior Gene Lab is:
Molecular Testing Laboratory:
Sema4
62 Southfield Ave
Stamford, CT 06902
Contact Information:
[email protected]
Tel: 800-298-6470
Fax: 646-859-6870
Sema4 Molecular Testing

Table 5. Genes Responsible for the Porphyrias
Porphyria Affected Enzyme Sequence in pathway Gene Symbol
XLP Delta-aminolevulinic acid synthase-2 1 ALAS2
ADP Delta-aminolevulinic acid synthase 2 ALAD
AIP Hydroxymethylbilane synthase (porphobilinogen deaminase) 3 HMBS
CEP Uroporphyrinogen III synthase 4 UROS
PCT & HEP Uroporphyrinogen decarboxylase 5 UROD
HCP Coproporphyrinogen oxidase 6 CPOX
VP Protoporphyrinogen oxidase 7 PPOX
EPP Ferrochelatase 8 FECH

At present Labcorp, ARUP, & Quest are not recommended for EPP testing.

Acute Porphyrias
An acute porphyria should be suspected if a patient presents with neurovisceral signs and symptoms and an initial evaluation excludes more common causes. The most important first-line screening test is measurement of urinary porphobilinogen (PBG). PBG is expected to be substantially increased in all patients during acute porphyria attacks but not in other medical conditions. Therefore, this test is both sensitive and specific for diagnosis of acute porphyria under most circumstances. An exception is ADP, in which ALA and porphyrins, but not PBG, are elevated.
Measurement of urine PBG should be combined with total urine porphyrins for first line testing. This is recommended even though porphyrin elevation is nonspecific, because porphyrins may remain increased longer than PBG in acute porphyrias (especially in HCP and VP). Also PBG is often less increased during attacks of HCP and VP than AIP. Urgent first line measurement of ALA is not essential, because ALA elevation from ADP or any other cause is always accompanied by increased porphyrins. Normal urine PBG and total porphyrins essentially rules out an acute porphyria as the cause of concurrent symptoms. However, slight elevations of PBG and porphyrins may not support a diagnosis of porphyria, especially with more sensitive methods that result in a narrow reference range.
A “stat” PBG is currently not available for rapid diagnosis of acute porphyria. While awaiting the report, initial management should be tailored to the possibility of acute porphyria, and include control of pain and other symptom, correcting fluid and electrolyte imbalances, and avoidance of medications that could worsen an attack (such as phenytoin for seizures). Patients with progressive neurological signs may be started on intravenous hemin before laboratory confirmation of acute porphyria is achieved, if the index of suspicion is high. Intravenous dextrose can be administered while hemin is being obtained but should not delay hemin administration.
This first line testing is inexpensive and can be done often, even when the index of suspicion for acute porphyrias is not high. When marked elevation in PBG establishes a diagnosis of either AIP, HCP or VP, more extensive second line biochemical and genetic testing can be justified to differentiate these conditions. Elevation in urine porphyrins without elevation in PBG also requires further evaluation by second line testing, to include urine ALA and plasma and fecal porphyrins, which if normal will exclude ADP, HCP and VP.
In a patient with known acute porphyria, the diagnosis of an attack is made on clinical grounds, and treatment can be initiated without waiting for urine PBG and porphyrin results. Recent experience suggests that patients on givosiran have many fewer attacks, but these are often not accompanied by elevations in urine ALA, PBG and porphyrins.
Standard Treatment
Treatment is specific to the type of Porphyria.
The basic defect cannot presently be treated, but significant effort is being directed toward treating the underlying mechanisms that cause symptoms.
Some people who are identified as having inherited an acute Porphyria do not have symptoms. It is important for those people, as well as for those who have symptoms, to be aware of preventive measures that may help them avoid episodes of Porphyria symptoms. These preventive measures include avoidance of certain drugs and alcohol for some types of Porphyria. For some people, they may also include avoidance of exposure to sunlight because sun sensitivity can occur with some types of Porphyria.
Some of the drugs that affected individuals may need to avoid include barbiturates, tranquilizers, birth control pills, sedatives, and alcohol. The Safe/Unsafe Drug List offers a complete assessment of the potential of drugs to provoke attacks of acute Porphyria and is intended for use by healthcare professionals.
An orphan drug known as Panhematin® (hemin for injection), is approved for use as a treatment for various forms of acute Porphyria and is administered intravenously. It is extremely potent, and its use typically follows a period of glucose therapy that has not produced the desired results.

Panhematin® for Acute Porphyria (AIP, VP, HCP, ADP)
Panhematin® is a treatment for the acute Porphyrias manufactured by Recordati Rare Diseases in Lebanon New Jersey. It is a lyophilized form of alkaline heme that has to be reconstituted immediately prior to administration. Panhematin® should be infused into a large peripheral vein. A large central line or port may be used, if available.
Doctors administer Panhematin® to correct heme deficiency in the liver and repress production of porphyrin precursors. Panhematin® almost always normalizes porphyrin and porphyrin precursor values. Three to four mg/kg of Panhematin® given once daily for four days early in an attack produces a highly beneficial effect in most patients. Commonly noted are decreases in pulse rate, blood pressure, abdominal pain, as well as decreased levels of urinary porphobilinogen (PBG). These effects can occur within a day.
Panhematin® is the only commercially available heme therapy in the United States. (Heme arginate is another preparation, but is only available outside of the U.S.) While a high carbohydrate diet is recommended for patients with Porphyria, it is not regarded as highly effective by itself. Intravenous glucose therapy is a treatment option for mild attacks. When heme therapy was introduced as a treatment, it was recommended that it be initiated only after several days of glucose therapy was unsuccessful.
Today, physicians experienced in treating patients with attacks of Porphyria recommend early use of Panhematin® rather than waiting to see if glucose alone will be of decisive help.
GIVLAARI for Acute Porphyria (AIP, VP, HCP, ADP)
GIVLAARI is a treatment used to prevent acute hepatic porphyria (AHP) in adults. There are 4 types of AHP: acute intermittent porphyria (AIP), variegate porphyria (VP), hereditary coproporphyria (HCP), and ALA-dehydratase deficient porphyria (ADP). GIVLAARI is given once a month as a subcutaneous injection (under the skin) by a healthcare professional.
GIVLAARI is a double-stranded small interfering RNA (siRNA) therapeutic specifically targeting ALAS1 mRNA, reducing ALAS1 mRNA levels and leading to reductions in urinary ALA and PBG.1
ALA, delta-aminolevulinic acid; ALAS1, delta-aminolevulinic acid synthase 1; mRNA, messenger RNA; PBG, porphobilinogen.

Avoiding triggers is Treatment
Avoiding triggers such as not using medications known to trigger acute attacks. Ask your doctor for a list of safe and unsafe drugs. You can also look up ALL your drugs to see if there is reported porphyria triggering. Use the following link to look up all your medications and herbals. Perhaps share this link with your doctors: https://porphyriafoundation.org/drugdatabase/drug-safety-database-search/
*Not using alcohol or recreational drugs.
*Avoiding fasting and dieting that involves severe calorie restriction.
*Not smoking.
*Taking certain hormones to prevent premenstrual attacks.
*Minimizing sun exposure. When you’re outdoors, wear protective clothing, and use an opaque blocking sunscreen, such as one with zinc oxide. When indoors, use window filters.
*Treating infections and other illnesses promptly.
*Taking steps to reduce emotional stress.

These disorders are usually inherited, meaning they are caused by gene mutations link passed from parents to children. If you have porphyria, cells fail to change chemicals in your body—called porphyrins and porphyrin precursors—into heme, the substance that gives blood its red color.

Types of Acute Porphyrias
Four types of acute porphyrias affect the nervous system. Two of those types can also affect the skin. Symptoms for acute porphyrias develop over hours or days and last for days or weeks.

1. Types of acute porphyria
Type of Acute Porphyria Parts of the Body Affected Where Porphyrins or Porphyrin Precursors Build Up
acute intermittent porphyria nervous system liver
variegate porphyria nervous system and skin liver
hereditary coproporphyria nervous system and skin liver
delta-aminolevulinic acid (ALA) dehydratase deficiency porphyria nervous system liver

Four types of cutaneous porphyrias affect only the skin and cause chronic, or long lasting, symptoms. People with cutaneous porphyria may develop skin symptoms—such as blistering or pain—after their skin is exposed to sunlight.
Table 2. Types of cuteaneous porphyria
Type of Cutaneous Porphyria Parts of the Body Affected Where Porphyrins Build Up
porphyria cutanea tarda Skin liver
protoporphyrias: erythropoietic protoporphyria and x-linked protoporphyria Skin bone marrow
congenital erythropoietic porphyria Skin bone marrow
hepatoerythropoietic porphyria Skin liver
How common are porphyrias?
Porphyrias are rare diseases. Studies suggest that all types of porphyrias combined affect fewer than 200,000 people in the United States.1
The most common type of acute porphyria is acute intermittent porphyria.
The most common type of cutaneous porphyria—and the most common type of porphyria overall—is porphyria cutanea tarda, which affects about 5 to 10 out of every 100,000 people.2
The most common type of porphyria in children is a cutaneous porphyria called erythropoietic protoporphyria.3
Who is more likely to get porphyria?
Acute porphyria is more common in females than in males and often begins when people are between the ages of 15 and 45.4
Among types of cutaneous porphyria, porphyria cutanea tarda most often develops in people older than age 40, usually men.2 For other types of cutaneous porphyria, symptoms often appear in early childhood.
What are the complications of porphyrias?
Different types of porphyrias may lead to different complications.
Liver problems
Several types of porphyrias can cause liver problems. Acute porphyria increases the chance of developing liver cancer NIH external link. Porphyria cutanea tarda can damage the liver and increase the chance of developing cirrhosis and liver cancer. Some people with protoporphyria also develop liver damage and cirrhosis, and up to 5 percent of people with protoporphyria develop liver failure.5
In people with protoporphyria, bile carries extra porphyrins from the liver to the gallbladder, which may lead to gallstones that are made of porphyrins.
Anemia
Two types of cutaneous porphyria, congenital erythropoietic porphyria and, less commonly, hepatoerythropoietic porphyria, may cause severe anemia. These diseases may also cause the spleen to become enlarged, which can make anemia worse.
High blood pressure and kidney problems
People with acute porphyria have an increased chance of developing high blood pressure and chronic kidney disease, which can lead to kidney failure.

TREATING BOTH TYPES OF PORPHYRIA
1) Acute porphyrias
Treatment of acute porphyria attacks focuses on providing rapid treatment of symptoms and preventing complications. Treatment may include:
• Injections of hemin, a medication that is a form of heme, to limit the body’s production of porphyrins
• Intravenous sugar (glucose), or sugar taken by mouth, if able, to maintain an adequate intake of carbohydrates
• Hospitalization for treatment of symptoms, such as severe pain, vomiting, dehydration or problems breathing
In 2019, the FDA approved givosiran (Givlaari) as a monthly injection for adults with acute hepatic porphyria to reduce the number of porphyria attacks. But it’s important to discuss safety information and potential serious side effects with your doctor. These include but are not limited to nausea, liver and kidney toxicity, and a small risk of anaphylaxis.
2) Cutaneous porphyrias
Treatment of cutaneous porphyrias focuses on reducing exposure to triggers such as sunlight and reducing the amount of porphyrins in your body to help eliminate your symptoms. This may include:
• Periodically drawing blood (phlebotomy) to reduce the iron in your body, which decreases porphyrins.
• Taking a drug used to treat malaria — hydroxychloroquine (Plaquenil) or, less often, chloroquine (Aralen) — to absorb excess porphyrins and help your body get rid of them more quickly than usual. These medications are generally used only in people who can’t tolerate a phlebotomy.
• A dietary supplement to replace vitamin D deficiency caused by avoidance of sunlight.

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