Porphyria Diagnosis and Clinical Features

Introduction to Porphyrias

Porphyrias are rare inborn errors of metabolism caused by abnormal functioning of heme biosynthesis enzymes, presenting with various clinical manifestations ranging from acute neurovisceral attacks to chronic skin symptoms, requiring biochemical testing for definitive diagnosis as clinical features alone are insufficient for establishing the diagnosis 1, 2

Acute hepatic porphyrias, including acute intermittent porphyria (AIP), variegate porphyria (VP), hereditary coproporphyria (HCP), typically become symptomatic in early adulthood 1
Acute neurovisceral attacks are characterized by severe abdominal pain, neuropsychiatric symptoms, and other symptoms 1
Cutaneous porphyrias, including porphyria cutanea tarda (PCT), erythropoietic protoporphyria (EPP), X-linked protoporphyria (XLP), and congenital erythropoietic porphyria (CEP), present with skin manifestations such as bullae on sun-exposed areas, acute painful photosensitivity 1

Biochemical testing is essential and must precede genetic testing, and diagnosis depends on demonstration of typical patterns of heme precursors in urine, feces, and blood 1, 2, 4
Specific tests for acute porphyrias include checking random urinary porphobilinogen (PBG) and measuring urinary 5-aminolevulinic acid (ALA) and PBG 1

Most porphyrias are hereditary, with various inheritance patterns, including autosomal dominant, autosomal recessive, and X-linked 1, 3, 4
For suspected porphyria, consult with an expert center or porphyria specialist laboratory, and a complete diagnostic evaluation should include biochemical testing, genetic testing, and complete medical history and physical examination 1, 2, 3, 4