Porphyria and Errors in Heme Metabolism Jonathan Ko, Michael Latayan, Patrick Hopper, Yameen Ingar November 6, 2018 PHM142 Fall 2018 Instructor: Dr. J. Henderson

What Are Porphyrias? Porphyrias are a group of 8 heme synthesis disorders that can cause nerve or skin problems It is when your cells fail to change body chemicals called porphyrins or porphyrin precursors into heme Buildup of porphyrin and/or its precursors cause illness Heme is important; is a major component of both myoglobin and hemoglobin Also used in the liver for the synthesis of cytochrome P450 (PK drug metabolism) 2 Major Types: Cutaneous porphyrias (porphyrias affecting the skin) Sometimes called the Vampire Disease - similar effects to vampire legends Photosensitivity and shrunken gums Acute porphyrias (porphyrias affecting the nervous system) The most common type of porphyria is porphyria cutanea tarda (PCT) Effects can vary: can do nothing to some but can be life threatening to others Many people live their lives never knowing they have it

Causes Is mainly hereditary - can be passed from parents to their children Can be autosomal dominant or recessive, or even X linked, with dominant being the most common Symptoms do not occur right away; usually people don’t realize they have it until a trigger causes symptoms to appear Possible Triggers: Alcohol consumption Smoking Sunlight Stress Certain medications Eating disorders The different types of porphyrias can have different triggers For example, porphyria cutanea tarda (PCT) has been known to be triggered by HIV, iron or lead accumulation and Hepatitis C

Symptoms Symptoms vary in cutaneous and acute porphyria Cutaneous: Occur continuously Oversensitivity to sunlight Blisters on exposed skin → itching and swelling Acute: Occur spontaneously or develop with time Pain in abdomen, chest, limbs, back Constipation & urinary retention Muscle weakness and seizures https://i0.wp.com/www.healthline.com/hlcmsresource/images/Clinical-Large-Images/648x364_Porphyrias.jpg?w=1155 https://i.ndtvimg.com/i/2017-06/constipation_696x400_51496740282.jpg

General Diagnosis Involve blood, urine and stool tests → detect high levels of porphyrin & its precursors, and DNA testing (gene mutations) Often, due to ambiguity of symptoms acute porphyria is misdiagnosed Common methods of Acute Porphyria: PBG - intermediate in porphyrin formation; via urine Individual acute porphyrias require analysis of urine, plasma and fecal porphyrias Common methods of Cutaneous Porphyria: EDTA blood sample for plasma porphyrin fluorescence emission spectroscopy Whole blood analysis for porphyrin PBG = Porphobilinogen, which is an intermediate in porphyrin synthesis, is detected via urine test → urine concent. tested via measuring creatinine concentration Test involves a validated quantitative ion-exchange resin-based method or LC-MS Cutaneous: EDTA or (Ethylenediamine tetra acetic acid) blood sample for plasma porphyrin https://www.umweltbundesamt.de/en/topics/health/commissions-working-groups/human-biomonitoring-commission/reference-hbm-values

Heme Metabolism & Deficiencies Causing Porphyria

Normal Heme Biosynthesis Glycine & Succinyl-CoA 2) ALA Molecules ALA Synthase (ALAS) PBG Synthase 5 aminolevulinic acid (ALA) Porphobilinogen (PBG) http://www.bloodjournal.org/content/89/1/1?sso- checked=true

Normal Heme Biosynthesis 3) PBG PBG Deaminase Tetrapyrol hydroxymethybilane (HMB) 4) HMB Uro’gen synthase Uroporphyrinogen (Uro’gen) http://www.bloodjournal.org/content/89/1/1?sso-checked=true

Normal Heme Biosynthesis 5) Uro’gen Uroporphyrinogen decarboxylase (UROD) Coproporphyrinogen (Copro’gen) 6) Copro’gen Coproporphyrinogen oxidase Protoporphyrinogen http://www.bloodjournal.org/content/89/1/1?sso-checked=true

Normal Heme Biosynthesis 7) Protoporphyrinogen Protoporphyrinogen oxidase Protoporphyrin IX (PP) 8) Protoporphyrin IX + Ferrous Iron Ferrochelatase Heme http://www.bloodjournal.org/content/89/1/1?sso-checked=true

Types of Porphyria and Deficient Enzyme - Delta-aminolevulinate-dehydratase deficiency porphyria - Acute intermittent porphyria - Hereditary coproporphyria - Variegate porphyria - Congenital erythropoietic porphyria - Porphyria cutanea tarda - Hepatoerythropoietic porphyria - Erythropoietic protoporphyria Deficient enzyme: → Delta-aminolevulinic acid dehydratase (liver) → Porphobilinogen deaminase (liver) → Coproporphyrinogen oxidase (liver) → Protoporphyrinogen oxidase (liver) → Uroporphyrinogen III cosynthase (b. marrow) → Uroporphyrinogen decarboxylase - 90% (liver) → Uroporphyrinogen decarboxylase - 90% (b. marrow) → Ferrochelatase - 75% (b. marrow)

Porphyria Cutanea Tarda (PCT) Most common type of Porphyria, affecting 1/20,000 Deficiencies in UROD Three types: Type 1: Most common type of PCT Acquired (Sporadic) Deficiency of UROD Activity Only in Liver Cells Type 2: Inherited - Autosomal Dominant form Minority of cases 50% reduction in UROD Activity Type 3: Underlying mechanism unknown Rare https://themedicalbiochemistrypage.org/pct.php

Diagnosis & Treatment Acute Intermittent Porphyria, Porphyria Cutanea Tarda AIP, , PP

Diagnosis - Acute Intermittent Porphyria Presentation Healthy young woman with days of severe fatigue and lack of concentration Severe abdominal pain Nausea, vomiting, weakness Analgesics ineffective Tachycardia, Elevated systole Elevated porphobilinogen plasma/urine levels Triad: hyponatremia, abdominal pain, seizure Colorless urine but light exposure turns it dark Elevated porphobilinogen in plasma/urine 10-150x normal not part of normal porphyrin screen Due to porphobilinogen deaminase deficiency Deficiency in heme in neuronal cells/build up of ALA (delta aminolevulinic acid) Lack of antianalgesic response = ppl think psychosomatic pain/drug addict Autosomal dom. Environmental factors can trigger catamenail/medication triggers/reduced calories https://www.researchgate.net/figure/Urine-sample-obtained-from-patient-20-during-the-porphyric-attack-with-dark-port-wine_fig4_23139861

Treatment - Acute Intermittent Porphyria Review medications Administer fluids, antiemetics, analgesics, antiseizure IV heme (Panhematin) Decrease porphobilinogen levels Gene therapy siRNA of delta-aminolevulinic acid synthase 1 Liver transplant Meds/environment can trigger Antiemetic: antibarf Analgesics: pain Gene therapy introduce normal working enzyme siRNA to reduce toxic levels that accumulate of dALA Liver transplant works too From Bissell et. al (2017).

Diagnosis- Porphyria Cutanea Tarda Presentation 40 years with skin friability, chronic blister lesions on sun exposed facial hair on women urine/plasma porphyrin profile has uroporphyrin & heptacarboxyporphyrin Excess uroporphyrin turns urine red-brown https://www.healthline.com/health/porphyria-cutanea-tarda#pictures photosensitivity: excitation and release = injury to skin Due to uroporphyrinogen decarboxylase inhibition; leads to build up Excess hepatic iron plays role

Treatment - Porphyria Cutanea Tarda Iron depletion/chelators Reduce risk factors Antimalarials hydroxychloroquinone/chloroquinone First point: shown to reduce remission of symptoms Draw blood frequently A Hydroxychloroquinones (antimarials) Helps hepatocytes mobilize porphyrins for urinary excretion From Bissell et. al (2017).

Summary Porphyrias are a group of 8 heme synthesis disorders in one of the 8 heme biosynthesis pathway enzymes, that can cause nervous system (acute) or skin (cutaneous) problems Disorders cause porphyrin or porphyrin precursor accumulation, which lead to illness Mainly hereditary Generally diagnosed with blood, urine and stool tests: looking for increased levels of porphyrins and their precursors Porphyria Cutanea Tarda (PCT) is the most common type of cutaneous porphyria Symptoms - blisters and photosensitivity Treatments - can prescribe antimalarials

Summary cont.

References Besur, S., Hou, W., Schmeltzer, P., & Bonkovsky, H. (2014). Clinically Important Features of Porphyrin and Heme Metabolism and the Porphyrias. Metabolites, 4(4), 977-1006. Bissell DM., Anderson KE., Bonkovsky HL. (2017). Porphyrias. N Engl J Med, 377(9), 862-872 Bonkovsky, H., Poh-Fitzpatrick, M., Pimstone, N., Obando, J., Di Bisceglie, A., & Tattrie, C. et al. (1998). Porphyria cutanea tarda, hepatitis C, and HFE gene mutations in north america. Hepatology, 27(6), 1661-1669. National Institution of Diabetes and Digestive and Kidney Diseases. (2014). Porphyria. National Institution of Diabetes and Digestive and Kidney Diseases. https://www.niddk.nih.gov/health-information/liver-disease/porphyria Puy, H., Gouya, L., & Deybach, J. (2010). Porphyrias. The Lancet, 375(9718), 924-937. Szlendak, U., Bykowska, K., & Lipniacka, A. (2016). Clinical, Biochemical and Molecular Characteristics of the Main Types of Porphyria. Advances In Clinical And Experimental Medicine, 25(2), 361-368. Woolf, J., Marsden, J. T., Degg, T., Whatley, S., Reed, P., Brazil, N., … Badminton, M. (2017). Best practice guidelines on first-line laboratory testing for porphyria. Annals of Clinical Biochemistry, 54(2), 188–198.

References (cont.) Szlendak, U., Bykowska, K., & Lipniacka, A. (2016). Clinical, Biochemical and Molecular Characteristics of the Main Types of Porphyria. Advances In Clinical And Experimental Medicine, 25(2), 361-368. doi: 10.17219/acem/58955 Bonkovsky, H., Poh-Fitzpatrick, M., Pimstone, N., Obando, J., Di Bisceglie, A., & Tattrie, C. et al. (1998). Porphyria cutanea tarda, hepatitis C, and HFE gene mutations in north america. Hepatology, 27(6), 1661-1669. doi: 10.1002/hep.510270627 Besur, S., Hou, W., Schmeltzer, P., & Bonkovsky, H. (2014). Clinically Important Features of Porphyrin and Heme Metabolism and the Porphyrias. Metabolites, 4(4), 977-1006. doi: 10.3390/metabo4040977