Overview of Porphyrias By Herbert L Bonkovsky, MD, Wake Forest University School of Medicine; Sean R Rudnick, MD, Wake Forest University School of Medicine Reviewed / Revised Dec 2022 View Patient Education Etiology Pathophysiology Diagnosis Secondary Porphyrinuria Topic Resources Substrates and Enzymes of... Major Features of the Two... Screening for Porphyrias Porphyrias are rare disorders in which there are defects in the pathway of heme synthesis due to genetic or acquired deficiencies of enzymes of the heme biosynthetic pathway.