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Porphyrias are a rare, heterogeneous group of inherited or acquired metabolic disorders caused by defects in the enzymes of the haem biosynthesis pathway. These defects result in the accumulation of porphyrins or their precursors, which are toxic to the nervous system and skin.
The condition is classically divided into:
Acute hepatic porphyrias (AHPs): Present with episodic abdominal pain, neuropsychiatric symptoms, autonomic dysfunction, and potentially life-threatening neuropathy.
Cutaneous porphyrias: Present with photosensitivity, blistering, and skin fragility.
Although porphyria is rare, its presentations may mimic common conditions in primary care (e.g. recurrent abdominal pain, anxiety, neuropathy, or skin rashes), leading to diagnostic delay.
| Aspect | Key Information |
|---|---|
| What is Porphyria? | A group of rare inherited metabolic disorders affecting heme biosynthesis due to enzyme deficiencies. Accumulation of toxic porphyrin precursors causes either acute neurovisceral attacks or chronic skin photosensitivity. |
| Types & Prevalence | Acute hepatic: Acute Intermittent Porphyria (AIP, 1:10,000–20,000), Variegate Porphyria (VP), Hereditary Coproporphyria (HCP). Cutaneous: Porphyria Cutanea Tarda (PCT, most common, 1:10,000), Erythropoietic Protoporphyria (EPP, 2.3:100,000). Extremely rare: Congenital Erythropoietic Porphyria (CEP), ALA Dehydratase Deficiency Porphyria (ADP, <10 cases reported). |
| Inheritance | Most are autosomal dominant with low penetrance (~12.7% in families, 0.5–1% general population).... |
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