The porphyrias may be inherited as either autosomal dominant (caused by inheriting 1 abnormal copy of the gene) or autosomal recessive (requires inheritance of 2 abnormal genes) traits, depending on which type of porphyria is involved. Some types of porphyria begin in early childhood, some at puberty, and others begin during adulthood. A classical attack of acute porphyria generally begins with colicky abdominal pain (severe), and is then followed by vomiting and constipation. Personality changes may develop during an acute attack, in addition to peripheral paresthesia (numbness and tingling), weakness, paralysis, sensory changes, and muscle pain. Acute attacks can be life-threatening, producing severe electrolyte imbalances, low blood pressure, and shock. Urine may become red or brown following an attack. Exposure to sunlight can cause reddening, pain, sensations of heat, blistering, and edema in the skin. These lesions heal slowly, often with scarring or pigment changes and may be disfiguring.
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