Learn / FMK
Every FMK condition
299 diseases, deficiencies, toxicities and drug mechanisms harvested from every FMK deck — the ones sprinkled through a single bullet as much as the ones with their own slide. Pick what you're given and what you have to name, or let it cycle; distractors come from the same category so you have to discriminate (hypoketotic vs. ketotic hypoglycemia, which GSD, which urea-cycle enzyme…). Every answer shows the whole card with the lecture and slide.
Heme · FMK 08.4
Congenital erythropoietic porphyria (Gunther disease, CEP) Autosomal recessive
Defect / target: Uroporphyrinogen III synthase (cosynthase) - step 4
Mechanism: Without the cosynthase, hydroxymethilbilane cyclizes nonenzymatically into the symmetric type I isomer, a metabolic dead end; uroporphyrin I and coproporphyrin I accumulate in erythroid cells and skin and are photoreactive.
↑ Accumulates: Uroporphyrinogen/uroporphyrin I and coproporphyrin I (type I isomers)· ↓ Deficient: Uroporphyrinogen III and heme
Presentation: Severe cutaneous photosensitivity with blistering and mutilation from infancy, skin fragility, red-brown urine, hemolysis; erythropoietic origin
Labs: Elevated type I porphyrins in urine and RBCs; erythrodontia/fluorescence under UV
Treatment: Strict sun avoidance; transfusion, marrow transplant in severe disease
Wrong (type I) isomer = dead end; after ring closure = cutaneous only
Learn the mechanism: Heme synthesis (porphyrias) →
FMK 08.4 Heme Metabolism · slide 10, 14, 17