Coproporphyria

Coproporphyria Coproporphyria is a rare metabolic disorder that affects the body's ability to produce heme, an essential component of hemoglobin. This condition is part of a group of disorders known as porphyrias, which are characterized by an accumulation of porphyrins or porphyrin precursors due to defects in the heme biosynthesis pathway.

Coproporphyria - overview

Coproporphyria is primarily caused by a deficiency of the enzyme coproporphyrinogen oxidase, which is responsible for converting coproporphyrinogen III to protoporphyrinogen IX in the heme biosynthesis pathway. This enzyme deficiency leads to the accumulation of coproporphyrinogen and other porphyrin precursors in the body.

Types of Coproporphyria

There are two main types of coproporphyria:

• Hereditary Coproporphyria (HCP): This is the most common form and is inherited in an autosomal dominant pattern. It is caused by mutations in the CPOX gene.
• Acquired Coproporphyria: This form is less common and can be triggered by environmental factors such as certain drugs, alcohol, or hormonal changes.

Symptoms

The symptoms of coproporphyria can vary widely and may include: - Abdominal pain - Neurological symptoms such as seizures, neuropathy, and mental disturbances - Skin sensitivity to sunlight, leading to blistering and scarring - Dark urine due to the presence of excess porphyrins The severity and combination of symptoms can differ from person to person, and some individuals may remain asymptomatic.

Diagnosis

Diagnosis of coproporphyria involves:

• Biochemical Tests: Measuring the levels of porphyrins and their precursors in urine, blood, and stool.
• Genetic Testing: Identifying mutations in the CPOX gene to confirm hereditary coproporphyria.

Treatment

Management of coproporphyria focuses on:

• Avoidance of Triggers: Patients are advised to avoid drugs, alcohol, and other factors that can precipitate attacks.
• Symptomatic Treatment: Pain management, anti-seizure medications, and other supportive therapies.
• Heme Therapy: Administration of heme arginate or hematin to reduce the production of porphyrin precursors.

Prognosis

The prognosis for individuals with coproporphyria varies. With proper management and avoidance of triggers, many patients can lead normal lives. However, severe attacks can lead to complications if not treated promptly.

See Also

• Porphyria
• Heme Biosynthesis
• Genetic Disorders

References

- "The Porphyrias: A Story of Inheritance and Environment," Journal of Rare Diseases. - "Clinical Management of Porphyrias," American Journal of Medicine.

NIH genetic and rare disease info

• NIH info on Coproporphyria

Coproporphyria is a rare disease.