Introduction:
Hereditary coproporphyria (HCP) is associated with a disorder known as porphyria. This disorder contains abnormally high levels of porphyrin precursors, and often porphyrins, due to a deficiency of certain enzymes essential for the formation (synthesis) of heme, parts of hemoglobin, and other heme proteins. Symptoms associated with different forms of porphyria are various. People with one type of porphyria do not develop a different kind of porphyria.
Porphyria is generally divided into two groups: liver type and erythropoiesis type. Porphyrins and porphyrin precursors and related substances are over-derived from the liver in the liver type and the bone marrow in the erythropoietic type. Porphyria with cutaneous symptoms is sometimes called cutaneous porphyria. Acute porphyria denotes porphyria, which can be accompanied by sudden pain attacks and other neurological symptoms. Most forms of porphyria are hereditary metabolic disorders. HCP is an acute liver-type porphyria.
What Is Hereditary Coproporphyria?
Hereditary coproporphyria (HCP) belongs to porphyria, a disease associated with heme metabolism defects that lead to the hypersecretion of porphyrins and porphyrin precursors. It is an inherited autosomal chromosome.
Though HCP is a rare disorder yet, it affects both genders in equal numbers. However, its manifestations are more commonly seen in females. The definite incidence and prevalence of HCP are still unspecified.
What Causes Hereditary Coproporphyria?
Mutations in the CPOX gene predispose individuals to HCP. The CPOX gene produces the enzyme coproporphyrinogen III oxidase (CPO). Therefore, mutations in the CPOX gene can reduce the activity of CPO in the body (about 50 % reduction), resulting in inadequate heme production and the accumulation of CPO precursors in the liver.
Many of the triggers for acute attacks increase the need for heme, raising concerns about CPO deficiency. Mutations in the genes underlying HCP limit the production of heme and increase the accumulation of porphyrin precursors in the body. Also, causing acute attacks. The problematic drug is not metabolized or eliminated from the body, causing acute attacks.
What Are the Symptoms Seen With Hereditary Coproporphyria?
Acute hepatic porphyria can show the following symptoms in the suspected individuals:
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At least 48 hours of intermittent recurrent body aches that usually affect the abdomen and lower back can become chronic. Pain in these areas is often the first sign of an attack.
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At least 48 hours of nausea.
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Family history of newly developed seizures.
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Hyponatremia (occurs when the sodium level in the blood is abnormally low. Sodium is an electrolyte and helps regulate the amount of water in and around the cell).
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Porphyria (accumulation of certain chemicals associated with proteins in red blood cells).
Chronic cutaneous porphyria is suspected in individuals with blisters and fragility of the sun-exposed skin, resulting in depigmented scars. However, skin signs appear only in a few heterozygotes, even during acute relapse.
How Is Hereditary Coproporphyria Diagnosed?
The HCP diagnosis is based on identifying characteristic symptoms, a detailed patient and family history, thorough clinical evaluation, and various specialized tests.
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The observation of reddish-brown urine free of blood indicates but is not conclusive acute porphyria. Patients with HCP may have elevated levels of urinary porphyrins, such as coproporphyrins, but it is not confirmatory (it can also be associated with other conditions).
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Tolerance to drugs such as oral contraceptives also indicates acute porphyria.
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Screening tests help diagnose HCP by measuring the levels of specific porphyrin precursors in the urine (such as porphobilinogen [PBG] and delta-aminolevulinic acid [ALA]). However, further testing is needed to exclude HCP from variegated or acute intermittent porphyria.
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Fecal CP analysis is beneficial in making a diagnosis. This test can detect significantly elevated coproporphyrin levels in stool samples. This is a characteristic of HCP and confirms the HCP diagnosis.
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Molecular genetic testing can identify the mutations in the CPOX gene. Therefore, families of people who favor the CPOX mutation may be advised to test for the mutation.
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HCPs need to be counseled to contain the risk of future acute attacks.
How Is Hereditary Coproporphyria Treated?
Treatment of HCP is based on the specific symptoms presented by each individual.
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The first step includes ceasing medications that can potentially aggravate HCP or cause an attack. All triggering factors should be eliminated or changed. In addition, ensuring proper intake of carbohydrates, either orally or intravenously.
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Treatment of HCP includes medicines that treat specific symptoms, such as certain analgesics (for pain), anxiety medicines, blood pressure-lowering medicines, nausea and vomiting, tachycardia, and restlessness. An affected individual may also need medication to treat an infection that may occur simultaneously with the attack (co-infection).
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Seizures may require treatment with antiepileptic drugs (anticonvulsants), but many of the standard options can exacerbate the seizures and are contraindicated. Short-acting Benzodiazepines or magnesium can be prescribed. Gabapentin and Propofol are safe choices for long-term seizure control.
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For individuals who develop skin complications, avoiding sunlight is beneficial and may involve using two layers of clothing. However, avoiding sunlight can lead to vitamin D deficiency, and some individuals may need supplemental vitamin D.
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Liver transplants have been used to treat some people with acute forms of porphyria and others with serious illnesses who have not responded to other treatment options. Liver transplantation in HCP patients is the last resort.
Conclusion:
Hereditary coproporphyria is a metabolic disease affected by a lack of the enzyme coproporphyrinogen oxidase. The enzyme deficiency causes the deposition of porphyrin precursors in the body. A mutation in the CPOX gene causes this enzyme deficiency. However, the lack alone is insufficient to bring out disease manifestations, and usually, people having CPOX gene mutation do not produce HCP symptoms.
Other factors like endocrine issues (hormonal changes), the use of certain drugs, regular alcohol consumption, recurrent infections, and drastic changes in the diet often trigger the onset of symptoms. Some patients experience acute seizures or episodes that develop over several days. The course and severity of the attack vary from person to person. In some cases, the condition can cause life-threatening complications, especially if not properly diagnosed and treated. CPOX mutations are autosomal dominant.
