This document discusses various types of porphyrias, which are disorders of heme biosynthesis. It describes the pathways of porphyrin synthesis and the enzymes involved at each step. It then classifies the main types of porphyria as either acute or non-acute, and lists examples such as acute intermittent porphyria, variegate porphyria, hereditary coproporphyria, porphyria cutanea tarda, congenital erythropoietic porphyria, ALAD deficiency porphyria, and erythropoietic protoporphyria. It indicates the tissues affected, inheritance, and abnormal metabolites detected in urine, feces, or blood for each type of porphy