porphyrin metabolism disease porphyria Represents both genetic and sporadic forms NANDO:1200811 SCTID:418470004 MESH:D011164 MONDO:0037939 MEDGEN:1844832 porphyria NCIT:C97096 UMLS:C5848305 Porphyria is a group of diseases in which substances called porphyrins build up, negatively affecting the skin or nervous system. Most types are inherited, but porphyria cutanea tarda may also be due to increased iron in the liver, hepatitis C, alcohol, or HIV/AIDS.