Inherited Porphyria

Mendelian MONDO:0019142 Pathograph 28 porphyria inborn disorder of porphyrin metabolism

Inherited porphyria is a heterogeneous group of hereditary heme-biosynthesis disorders. Each major subtype reflects a defect or dysregulation at a different enzymatic step, producing hepatic or erythropoietic accumulation of heme intermediates. Clinically, the group spans acute hepatic porphyrias with neurovisceral attacks and cutaneous or erythropoietic porphyrias with photosensitivity, blistering, or protoporphyrin-mediated phototoxic pain.

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3
Inheritance
7
Pathophys.
9
Phenotypes
28
Pathograph
8
Genes
7
Treatments
8
Subtypes
4
References
1
Deep Research
👪

Inheritance

3
Autosomal dominant inheritance HP:0000006
Several acute hepatic porphyrias, including acute intermittent porphyria, hereditary coproporphyria, and variegate porphyria, often follow autosomal dominant inheritance with low clinical penetrance.
Autosomal dominant inheritance
Show evidence (1 reference)
DOI:10.3389/fgene.2024.1374965 SUPPORT Other
"AIP is an autosomal dominant disorder characterized by low penetrance and a highly heterogenous clinical presentation."
The 2024 AIP review supports autosomal dominant inheritance and low penetrance for the major acute hepatic porphyria subtype.
Autosomal recessive inheritance HP:0000007
Some inherited porphyrias, including ALAD porphyria, congenital erythropoietic porphyria, and hepatoerythropoietic porphyria, follow autosomal recessive inheritance.
Autosomal recessive inheritance
X-linked inheritance HP:0001417
ALAS2-related X-linked protoporphyria is an X-linked inherited protoporphyria.
X-linked inheritance
◆

Subtypes

8
Acute Intermittent Porphyria MONDO:0008294
Acute hepatic porphyria caused by HMBS deficiency, with neurovisceral attacks and no primary blistering photosensitivity.
Porphyria due to ALA Dehydratase Deficiency MONDO:0013000
Ultra-rare autosomal recessive acute hepatic porphyria caused by ALAD deficiency.
Hereditary Coproporphyria MONDO:0007369
Acute hepatic porphyria caused by CPOX deficiency, often presenting with neurovisceral attacks and sometimes cutaneous lesions.
Variegate Porphyria MONDO:0008297
Acute hepatic porphyria caused by PPOX deficiency, with neurovisceral attacks with or without cutaneous photosensitivity.
Congenital Erythropoietic Porphyria
UROS-related erythropoietic porphyria characterized by early-onset photosensitivity, blistering, anemia, and porphyrin accumulation.
Familial Porphyria Cutanea Tarda MONDO:0008296
Inherited UROD-related porphyria cutanea tarda susceptibility with bullous photodermatitis.
Hepatoerythropoietic Porphyria MONDO:0019799
Very rare biallelic UROD-related chronic hepatic porphyria with severe bullous photosensitivity.
Erythropoietic Protoporphyria MONDO:0001676
Protoporphyrin-accumulating inherited porphyria, usually FECH-related or ALAS2-related, with painful cutaneous photosensitivity.
⚙

Pathophysiology

7
Heme Biosynthesis Enzyme Deficiency
Inherited porphyrias arise when pathogenic variants reduce activity of heme-biosynthesis enzymes or alter ALAS2 regulation, creating subtype- specific bottlenecks in porphyrin metabolism.
heme biosynthetic process link ↓ DECREASED porphyrin-containing compound metabolic process link ⚠ ABNORMAL
Downstream
Porphyrin Precursor and Porphyrin Accumulation Impaired pathway flux causes accumulation of pathway intermediates upstream of the defective enzymatic step.
Hepatic ALAS1 Induction and Acute Precursor Overproduction In acute hepatic porphyrias, inherited heme-enzyme defects require hepatic ALAS1 induction before acute attacks develop.
Erythroid Protoporphyrin IX Accumulation FECH reduction or erythroid ALAS2 gain of function alters the same heme biosynthesis pathway and produces protoporphyrin IX accumulation.
Erythroid Uroporphyrin I Accumulation and Hemolysis UROS loss reduces uroporphyrinogen synthase activity and creates a CEP branch with erythroid porphyrinogen accumulation and erythrocyte damage.
Show evidence (1 reference)
DOI:10.1146/annurev-med-042921-123602 SUPPORT Other
"The porphyrias are a group of rare diseases, each resulting from a defect in a different enzymatic step of the heme biosynthetic pathway."
This recent review directly supports the group-level mechanism as subtype-specific enzymatic defects in heme biosynthesis.
Porphyrin Precursor and Porphyrin Accumulation
Defective heme-biosynthesis flux causes subtype-specific accumulation of ALA, porphobilinogen, porphyrins, or protoporphyrin upstream of the blocked enzymatic step, generating hepatic, erythropoietic, cutaneous, renal, and hepatic complications.
porphyrin-containing compound metabolic process link ⚠ ABNORMAL heme biosynthetic process link ⚠ ABNORMAL
Downstream
Neurovisceral Attack Susceptibility ALA and PBG accumulation precedes acute porphyria symptoms.
Cutaneous Phototoxicity Photoreactive porphyrin or protoporphyrin accumulation drives light-triggered cutaneous injury.
Chronic kidney disease ALA and PBG precursor excess is associated with chronic tubulointerstitial kidney injury in AIP.
Abnormality of the liver Excess protoporphyrin eliminated through the hepatobiliary system can cause liver dysfunction.
Show evidence (2 references)
DOI:10.1146/annurev-med-042921-123602 SUPPORT Other
"They can be broadly divided into two categories, hepatic and erythropoietic porphyrias, depending on the primary site of accumulation of heme intermediates."
This review supports the shared porphyria mechanism of intermediate accumulation, with branch specificity by tissue compartment.
DOI:10.1182/hematology.2024000663 SUPPORT Other
"In 2019 the US Food and Drug Administration approved givosiran for AHP based on positive results from a phase 3 clinical trial of 94 patients with AHP who demonstrated a marked improvement in AHP attacks and a substantial decrease in δ-aminolevulinic acid and porphobilinogen, the primary disease..."
This review identifies ALA and PBG as primary acute hepatic porphyria disease markers.
Hepatic ALAS1 Induction and Acute Precursor Overproduction
In acute hepatic porphyrias, a germline defect in one of four heme-synthesis enzymes becomes clinically active when hepatic ALAS1 is induced, increasing ALA and PBG production and precipitating neurovisceral symptoms.
hepatocyte link
ALAS1 link
heme biosynthetic process link ↑ INCREASED
liver link
Downstream
Neurovisceral Attack Susceptibility ALAS1 induction increases ALA and PBG, the primary biochemical markers and toxic precursors of acute hepatic porphyrias.
Show evidence (2 references)
DOI:10.1182/hematology.2024000663 SUPPORT Other
"The acute hepatic porphyrias (AHPs) are a family of rare genetic diseases associated with attacks of abdominal pain, vomiting, weakness, neuropathy, and other neurovisceral symptoms."
This review links the acute hepatic porphyria group to neurovisceral attacks.
DOI:10.1182/hematology.2024000663 SUPPORT Other
"Pathogenic variants in 1 of 4 enzymes of heme synthesis are necessary for the development of AHP, and the onset of acute attacks also requires the induction of δ-aminolevulinic acid synthase 1 (ALAS1), the first and rate-limiting step of heme synthesis in the liver."
This supports the causal chain from inherited enzyme defects to liver-specific ALAS1 induction during attacks.
Erythroid Protoporphyrin IX Accumulation
EPP and X-linked protoporphyria involve reduced FECH activity or increased erythroid ALAS2 activity, producing protoporphyrin IX accumulation in erythroid cells and clinically severe visible-light phototoxicity.
erythroblast link
FECH link ALAS2 link
heme biosynthetic process link ⚠ ABNORMAL
skin of body link
Downstream
Cutaneous Phototoxicity Protoporphyrin IX accumulation causes severe light sensitivity and, in a minority, liver complications.
Abnormality of the liver Excess PPIX elimination through hepatobiliary pathways can produce liver dysfunction and rare liver failure.
Show evidence (2 references)
DOI:10.3390/ph17010031 SUPPORT Other
"Erythropoietic protoporphyria (EPP) is a genetic disorder stemming from reduced ferrochelatase expression, the final enzyme in the pathway of heme biosynthesis."
This review supports FECH deficiency at the final heme-biosynthesis step as the EPP mechanism.
DOI:10.3390/ph17010031 SUPPORT Other
"A closely related condition, X-linked protoporphyria (XLP), bears similar clinical features although it arises from the heightened activity of δ-aminolevulinic acid synthase 2 (ALAS2), the first and normally rate-controlling enzyme in heme biosynthesis in developing red blood cells."
This supports ALAS2 gain of function in the erythroid compartment for XLP.
Erythroid Uroporphyrin I Accumulation and Hemolysis
Congenital erythropoietic porphyria reflects absent or markedly reduced UROS enzymatic activity in erythroid heme synthesis, causing uroporphyrin I and coproporphyrin I accumulation, erythrocyte damage, and visible-light phototoxicity.
erythroblast link erythrocyte link
UROS link
heme biosynthetic process link ↓ DECREASED porphyrin-containing compound metabolic process link ⚠ ABNORMAL
Downstream
Cutaneous Phototoxicity Photoreactive uroporphyrinogen and coproporphyrinogen accumulation elicits visible-light phototoxicity.
Anemia Porphyrinogen-mediated erythrocyte damage causes chronic hemolytic anemia in CEP.
Thrombocytopenia Severe CEP can include cytopenias beyond hemolytic anemia.
Abnormal cornea morphology Chronic CEP phototoxic injury can involve the cornea.
Show evidence (1 reference)
PMID:30685241 SUPPORT Human Clinical
"Disease-causing mutations in either gene result in absent or markedly reduced UROS enzymatic activity. This in turn leads to the accumulation of the non-physiologic and photoreactive porphyrinogens, uroporphyrinogen I and coproporphyrinogen I, which damage erythrocytes and elicit a phototoxic..."
This review directly supports the CEP branch from UROS enzymatic deficiency to erythroid porphyrinogen accumulation, hemolysis, and phototoxicity.
Neurovisceral Attack Susceptibility
Acute hepatic porphyria subtypes can develop episodic neurovisceral attacks with abdominal pain, vomiting, weakness, neuropathy, and related symptoms.
heme biosynthetic process link ⚠ ABNORMAL
Downstream
Abdominal pain Acute hepatic porphyria attacks commonly present with abdominal pain.
Vomiting Acute neurovisceral attacks include gastrointestinal symptoms such as vomiting.
Peripheral neuropathy Acute hepatic porphyria attacks can include neuropathy.
Show evidence (1 reference)
DOI:10.1182/hematology.2024000663 SUPPORT Other
"The acute hepatic porphyrias (AHPs) are a family of rare genetic diseases associated with attacks of abdominal pain, vomiting, weakness, neuropathy, and other neurovisceral symptoms."
This evidence directly lists the clinical neurovisceral attack surface.
Cutaneous Phototoxicity
Cutaneous and erythropoietic porphyrias cause photosensitivity through accumulation of photoreactive porphyrins or protoporphyrin in skin, plasma, erythrocytes, or hepatobiliary tissues.
porphyrin-containing compound metabolic process link ⚠ ABNORMAL
skin of body link
Downstream
Cutaneous photosensitivity Phototoxic porphyrin or protoporphyrin accumulation manifests clinically as severe cutaneous photosensitivity.
Show evidence (1 reference)
DOI:10.3390/life14060689 SUPPORT Human Clinical
"Erythropoietic protoporphyria (EPP) and X-linked protoporphyria (XLP) are rare disorders of heme biosynthesis characterized by severe cutaneous phototoxicity."
A US clinical cohort directly supports severe cutaneous phototoxicity in EPP and XLP.
⬡

Pathograph

Use the checkboxes to hide or show graph categories. Hover nodes for evidence and cross-linked metadata.
Pathograph: causal mechanism network for Inherited Porphyria Interactive directed graph showing how pathophysiology mechanisms, phenotypes, genetic factors and variants, experimental models, environmental triggers, and treatments relate through causal and linked edges.
●

Phenotypes

9
Blood 2
Anemia Anemia (HP:0001903)
Show evidence (1 reference)
PMID:30685241 SUPPORT Human Clinical
"Chronic transfusion-dependent hemolytic anemia is common and leads to bone marrow hyperplasia, which further increases porphyrin production."
This review directly supports anemia as a common CEP manifestation.
Thrombocytopenia Thrombocytopenia (HP:0001873)
Show evidence (1 reference)
PMID:38576642 SUPPORT Human Clinical
"Laboratory investigations demonstrated anemia, leukocytopenia, thrombocytopenia, and elevated urine uroporphyrin 1 and coproporphyrin 1 levels."
This case report supports thrombocytopenia as part of the reported CEP hematologic phenotype.
Digestive 1
Vomiting Vomiting (HP:0002013)
Show evidence (1 reference)
DOI:10.1182/hematology.2024000663 SUPPORT Other
"The acute hepatic porphyrias (AHPs) are a family of rare genetic diseases associated with attacks of abdominal pain, vomiting, weakness, neuropathy, and other neurovisceral symptoms."
Vomiting is explicitly listed among acute hepatic porphyria attack manifestations.
Genitourinary 1
Chronic kidney disease Chronic kidney disease (HP:0012622)
Show evidence (1 reference)
PMID:25830761 SUPPORT Human Clinical
"Chronic kidney disease occurred in up to 59% of the symptomatic AIP patients, with a decline in the glomerular filtration rate of ~1 ml/min per 1.73 m(2) annually."
This review directly supports chronic kidney disease as a frequent complication in symptomatic acute intermittent porphyria.
Integument 1
Cutaneous photosensitivity Cutaneous photosensitivity (HP:0000992)
Show evidence (1 reference)
DOI:10.3390/life14060689 SUPPORT Human Clinical
"Erythropoietic protoporphyria (EPP) and X-linked protoporphyria (XLP) are rare disorders of heme biosynthesis characterized by severe cutaneous phototoxicity."
This cohort supports severe cutaneous phototoxicity in protoporphyrias.
Nervous System 1
Peripheral neuropathy Peripheral neuropathy (HP:0009830)
Show evidence (1 reference)
DOI:10.1182/hematology.2024000663 SUPPORT Other
"The acute hepatic porphyrias (AHPs) are a family of rare genetic diseases associated with attacks of abdominal pain, vomiting, weakness, neuropathy, and other neurovisceral symptoms."
Neuropathy is explicitly listed among acute hepatic porphyria attack manifestations.
Constitutional 1
Abdominal pain Abdominal pain (HP:0002027)
Show evidence (1 reference)
DOI:10.1182/hematology.2024000663 SUPPORT Other
"The acute hepatic porphyrias (AHPs) are a family of rare genetic diseases associated with attacks of abdominal pain, vomiting, weakness, neuropathy, and other neurovisceral symptoms."
Abdominal pain is explicitly listed among acute hepatic porphyria attack manifestations.
Other 2
Abnormal cornea morphology Abnormal cornea morphology (HP:0000481)
Show evidence (1 reference)
PMID:30685241 SUPPORT Human Clinical
"In addition, patients have erythrodontia (brownish discoloration of teeth) and can develop corneal scarring."
This review directly supports corneal involvement in CEP.
Abnormality of the liver Abnormality of the liver (HP:0001392)
Show evidence (1 reference)
DOI:10.3390/life13041066 SUPPORT Human Clinical
"In addition to the most prominent symptom of incapacitating phototoxic skin reactions, 20% of EPP patients exhibit disturbed liver functioning and 4% experience terminal liver failure caused by the hepatobiliary elimination of excess PPIX."
The study directly supports liver involvement in a subset of EPP patients.
🧬

Genetic Associations

8
Acute hepatic porphyria genes (Modifier)
Show evidence (1 reference)
DOI:10.1182/hematology.2024000663 SUPPORT Other
"Pathogenic variants in 1 of 4 enzymes of heme synthesis are necessary for the development of AHP, and the onset of acute attacks also requires the induction of δ-aminolevulinic acid synthase 1 (ALAS1), the first and rate-limiting step of heme synthesis in the liver."
This supports the two-part genetic and regulatory requirement for AHP attacks.
HMBS pathogenic variants (Causative)
Autosomal dominant
Show evidence (1 reference)
DOI:10.3389/fgene.2024.1374965 SUPPORT Other
"Acute intermittent porphyria (AIP) is caused by mutations in the gene encoding hydroxymethylbilane synthase (HMBS), a key enzyme in the heme biosynthesis pathway."
This directly supports HMBS as the causative AIP gene.
ALAD pathogenic variants (Causative)
Autosomal recessive
Show evidence (1 reference)
PMID:33199206 SUPPORT Human Clinical
"BACKGROUND: 5-Aminolevulinic acid dehydratase (ALAD) porphyria (ADP) is an ultrarare autosomal recessive disease, with only eight documented cases, all of whom were males."
This review directly supports ALAD porphyria as an autosomal recessive inherited porphyria subtype.
CPOX pathogenic variants (Causative)
Autosomal dominant
Show evidence (1 reference)
PMID:30385147 SUPPORT Human Clinical
"AIP, HCP, VP, and ADP each results from loss-of-function (LOF) mutations in their disease-causing genes: hydroxymethylbilane synthase (HMBS); coproporphyrinogen oxidase (CPOX); protoporphyrinogen oxidase (PPOX), and δ-aminolevulinic acid dehydratase (ALAD), respectively."
This review maps HCP to CPOX loss-of-function variants.
PPOX pathogenic variants (Causative)
Autosomal dominant
Show evidence (1 reference)
PMID:30385147 SUPPORT Human Clinical
"AIP, HCP, VP, and ADP each results from loss-of-function (LOF) mutations in their disease-causing genes: hydroxymethylbilane synthase (HMBS); coproporphyrinogen oxidase (CPOX); protoporphyrinogen oxidase (PPOX), and δ-aminolevulinic acid dehydratase (ALAD), respectively."
This review maps VP to PPOX loss-of-function variants.
UROS pathogenic variants (Causative)
Autosomal recessive
Show evidence (1 reference)
PMID:30685241 SUPPORT Human Clinical
"CEP is caused by mutations in the uroporphyrinogen synthase (UROS) gene."
This review directly supports UROS as the causative CEP gene.
UROD pathogenic variants (Causative)
Autosomal dominant or autosomal recessive
Show evidence (2 references)
PMID:30514647 SUPPORT Human Clinical
"Porphyria Cutanea Tarda (PCT) is a cutaneous porphyria that results from the hepatic inhibition of the heme biosynthetic enzyme uroporphyrinogen decarboxylase (UROD), and can occur either in the absence or presence of an inherited heterozygous UROD mutation (PCT subtypes 1 and 2, respectively)."
This molecular diagnostic cohort supports UROD variants in familial/type 2 porphyria cutanea tarda.
PMID:30514647 SUPPORT Human Clinical
"Hepatoerythropoietic Porphyria (HEP) is a rare autosomal recessive disease that results from homozygosity or compound heterozygosity for UROD mutations and often causes infantile or childhood onset of both erythropoietic and cutaneous manifestations."
This molecular diagnostic cohort supports biallelic UROD variants as causative for hepatoerythropoietic porphyria.
Protoporphyria genes (Causative)
Autosomal recessive or X-linked
Show evidence (2 references)
DOI:10.3390/ph17010031 SUPPORT Other
"Erythropoietic protoporphyria (EPP) is a genetic disorder stemming from reduced ferrochelatase expression, the final enzyme in the pathway of heme biosynthesis."
This directly supports FECH reduction in EPP.
DOI:10.3390/ph17010031 SUPPORT Other
"A closely related condition, X-linked protoporphyria (XLP), bears similar clinical features although it arises from the heightened activity of δ-aminolevulinic acid synthase 2 (ALAS2), the first and normally rate-controlling enzyme in heme biosynthesis in developing red blood cells."
This directly supports increased ALAS2 activity as the XLP mechanism.
💊

Treatments

7
Trigger avoidance and supportive care
Action: supportive care MAXO:0000950
Avoidance of unsafe medications, fasting, alcohol, tobacco, and other attack triggers is foundational for acute hepatic porphyrias; supportive care is needed during attacks.
Target Phenotypes: Abdominal pain ↗
Show evidence (1 reference)
DOI:10.3390/jcm13226779 SUPPORT Human Clinical
"The elimination of precipitating factors, hemin therapy, and pain relief are strategies used to treat porphyria symptoms, but are often reserved for patients suffering recurrent, acute attacks."
This real-world AIP study background supports trigger elimination and supportive symptom-directed care for acute attacks.
Hemin or heme arginate pharmacotherapy
Action: Pharmacotherapy NCIT:C15986
Agent: hemin ↗
Intravenous hemin or heme arginate is used for severe acute hepatic porphyria attacks to repress hepatic ALAS1 and lower precursor production.
Mechanism Target:
INHIBITS Hepatic ALAS1 Induction and Acute Precursor Overproduction — Heme therapy is used to suppress hepatic ALAS1-driven precursor overproduction during acute attacks.
Show evidence (1 reference)
DOI:10.3390/jcm13226779 SUPPORT Human Clinical
"The elimination of precipitating factors, hemin therapy, and pain relief are strategies used to treat porphyria symptoms, but are often reserved for patients suffering recurrent, acute attacks."
The real-world AIP study background supports hemin and supportive symptom-directed care for acute/recurrent attacks.
Givosiran pharmacotherapy
Action: Pharmacotherapy NCIT:C15986
Agent: givosiran ↗
Givosiran is an ALAS1-targeted siRNA therapy for acute hepatic porphyria that reduces ALA/PBG and lowers attack burden, with monitoring for liver, renal, injection-site, and homocysteine-related adverse effects.
Mechanism Target:
INHIBITS Hepatic ALAS1 Induction and Acute Precursor Overproduction — Givosiran inhibits hepatic ALAS1 mRNA to reduce ALA and PBG accumulation.
Show evidence (1 reference)
DOI:10.1182/hematology.2024000663 SUPPORT Other
"Givosiran is an RNA interference medication that inhibits hepatic ALAS1 and was designed to treat AHP."
This review directly states givosiran's ALAS1-targeted mechanism.
Show evidence (2 references)
DOI:10.1186/s13023-024-03284-w SUPPORT Human Clinical
"Givosiran therapy reduced annualized rates of porphyria attacks and hemin use by 97% and 96%, respectively."
The 48-month open-label extension provides direct clinical evidence for reduced attacks and hemin use.
DOI:10.3390/jcm13226779 SUPPORT Human Clinical
"Givosiran is effective in preventing severe acute attacks and reducing the chronic health burden in patients with acute intermittent porphyria."
The German real-world cohort supports effectiveness in patients with acute intermittent porphyria.
Bone marrow transplantation for severe CEP
Action: bone marrow transplantation MAXO:0010030
Bone marrow or hematopoietic stem cell transplantation can be curative in severe congenital erythropoietic porphyria.
Mechanism Target:
RESTORES Erythroid Uroporphyrin I Accumulation and Hemolysis — Hematopoietic stem cell or bone marrow transplantation can replace the diseased erythropoietic compartment and is considered curative in severe CEP.
Show evidence (1 reference)
PMID:38576642 SUPPORT Human Clinical
"Stem cell transplantation remains the sole curative therapy for this exceedingly rare condition."
The CEP case report and review supports transplantation as a curative intervention for the erythropoietic disease mechanism.
Target Phenotypes: Anemia ↗ Cutaneous photosensitivity ↗
Show evidence (2 references)
PMID:30685241 SUPPORT Human Clinical
"In severe transfection-dependent cases, bone marrow or hematopoietic stem cell transplantation has been performed, which is curative."
This review supports transplantation as curative therapy for severe CEP.
PMID:38576642 SUPPORT Human Clinical
"Stem cell transplantation remains the sole curative therapy for this exceedingly rare condition."
This case report and review supports stem cell transplantation as curative therapy for CEP.
Photoprotection
Action: supportive care MAXO:0000950
Sunlight and visible-light avoidance, protective clothing, and related measures reduce cutaneous phototoxic injury in photosensitive porphyrias.
Target Phenotypes: Cutaneous photosensitivity ↗
Show evidence (1 reference)
DOI:10.3390/ph17010031 SUPPORT Other
"Traditionally, managing EPP and XLP involved sun avoidance."
This review supports sun avoidance as traditional protoporphyria management.
Afamelanotide pharmacotherapy
Action: Pharmacotherapy NCIT:C15986
Agent: afamelanotide ↗
Afamelanotide is an alpha-melanocyte-stimulating hormone analogue and approved protoporphyria treatment that increases light tolerance and improves quality of life.
Mechanism Target:
MODULATES Cutaneous Phototoxicity — Afamelanotide improves light tolerance in EPP and XLP without correcting the underlying protoporphyrin accumulation.
Show evidence (2 references)
DOI:10.3390/life14060689 SUPPORT Human Clinical
"Afamelanotide, an α-melanocyte-stimulating hormone analogue, is the only approved treatment for protoporphyria and leads to increased light tolerance and improved quality of life (QoL)."
The US cohort directly supports afamelanotide as approved therapy that improves light tolerance and quality of life.
DOI:10.3390/life14060689 SUPPORT Human Clinical
"Among the patients who received ≥2 implants, the median time to symptom onset following sunlight exposure was 12.5 min (IQR, 5–20) prior to the initiation of afamelanotide and 120 min (IQR, 60–240) after treatment (p < 0.001)."
This provides direct clinical evidence for improved sunlight tolerance.
Dersimelagon pharmacotherapy
Action: Pharmacotherapy NCIT:C15986
Agent: dersimelagon ↗
Dersimelagon is an investigational oral MC1R agonist being developed for EPP and X-linked protoporphyria.
Mechanism Target:
MODULATES Cutaneous Phototoxicity — MC1R agonism is intended to prevent phototoxicity and related pain in EPP and XLP.
Show evidence (1 reference)
DOI:10.3390/ph17010031 PARTIAL Other
"However, the emergence of innovative therapies, such as dersimelagon, is reshaping the therapeutic landscape for these conditions."
The review supports dersimelagon as an emerging therapy; marked PARTIAL because this abstract-level evidence does not establish final clinical approval or long-term outcomes.
🔬

Biochemical Markers

3
Urinary 5-aminolevulinic acid (INCREASED)
Context: Increased urinary ALA is characteristic of acute hepatic porphyria attacks and is reduced by ALAS1-targeted therapy.
Pathograph Readouts
Readout Of Hepatic ALAS1 Induction and Acute Precursor Overproduction Positive Diagnostic
Increased urinary ALA reports hepatic ALAS1-driven precursor overproduction in acute hepatic porphyrias.
Show evidence (1 reference)
DOI:10.1182/hematology.2024000663 SUPPORT Other
"In 2019 the US Food and Drug Administration approved givosiran for AHP based on positive results from a phase 3 clinical trial of 94 patients with AHP who demonstrated a marked improvement in AHP attacks and a substantial decrease in δ-aminolevulinic acid and porphobilinogen, the primary disease..."
The review identifies ALA as one of the primary AHP disease markers and links its reduction to ALAS1-targeted therapy.
Show evidence (1 reference)
DOI:10.1182/hematology.2024000663 SUPPORT Other
"In 2019 the US Food and Drug Administration approved givosiran for AHP based on positive results from a phase 3 clinical trial of 94 patients with AHP who demonstrated a marked improvement in AHP attacks and a substantial decrease in δ-aminolevulinic acid and porphobilinogen, the primary disease..."
The review identifies ALA as one of the primary disease markers of AHP.
Urinary porphobilinogen (INCREASED)
Context: Increased urinary PBG supports most acute hepatic porphyrias during attacks, although ALAD porphyria is an exception because its enzymatic block is upstream of PBG formation.
Pathograph Readouts
Readout Of Hepatic ALAS1 Induction and Acute Precursor Overproduction Positive Diagnostic
Increased urinary PBG reports acute hepatic porphyria precursor overproduction downstream of ALAS1 induction.
Show evidence (1 reference)
DOI:10.1182/hematology.2024000663 SUPPORT Other
"In 2019 the US Food and Drug Administration approved givosiran for AHP based on positive results from a phase 3 clinical trial of 94 patients with AHP who demonstrated a marked improvement in AHP attacks and a substantial decrease in δ-aminolevulinic acid and porphobilinogen, the primary disease..."
The review identifies PBG as one of the primary AHP disease markers and links its reduction to ALAS1-targeted therapy.
Show evidence (1 reference)
DOI:10.1182/hematology.2024000663 SUPPORT Other
"In 2019 the US Food and Drug Administration approved givosiran for AHP based on positive results from a phase 3 clinical trial of 94 patients with AHP who demonstrated a marked improvement in AHP attacks and a substantial decrease in δ-aminolevulinic acid and porphobilinogen, the primary disease..."
The review identifies PBG as one of the primary disease markers of AHP.
Erythrocyte or plasma protoporphyrin (INCREASED)
Context: Elevated protoporphyrin is the central biochemical abnormality in EPP and X-linked protoporphyria.
Pathograph Readouts
Readout Of Erythroid Protoporphyrin IX Accumulation Positive Diagnostic
Increased erythrocyte or plasma protoporphyrin reports protoporphyrin IX accumulation in EPP/XLP.
Show evidence (1 reference)
DOI:10.3390/ph17010031 SUPPORT Other
"Both of these abnormalities result in the buildup of protoporphyrin IX, leading to excruciating light sensitivity and, in a minority of cases, potentially fatal liver complications."
The review identifies protoporphyrin IX buildup as the biochemical abnormality downstream of FECH or ALAS2 defects.
Show evidence (1 reference)
DOI:10.3390/ph17010031 SUPPORT Other
"Both of these abnormalities result in the buildup of protoporphyrin IX, leading to excruciating light sensitivity and, in a minority of cases, potentially fatal liver complications."
The review directly supports protoporphyrin IX buildup in EPP and XLP.
{ }

Source YAML

click to show 
name: Inherited Porphyria
creation_date: "2026-05-10T15:02:44Z"
updated_date: "2026-05-19T04:59:34Z"
category: Mendelian
description: >-
  Inherited porphyria is a heterogeneous group of hereditary heme-biosynthesis
  disorders. Each major subtype reflects a defect or dysregulation at a
  different enzymatic step, producing hepatic or erythropoietic accumulation of
  heme intermediates. Clinically, the group spans acute hepatic porphyrias with
  neurovisceral attacks and cutaneous or erythropoietic porphyrias with
  photosensitivity, blistering, or protoporphyrin-mediated phototoxic pain.
synonyms:
- hereditary porphyria
- porphyria
- disorder of porphyrin and heme metabolism
disease_term:
  preferred_term: inherited porphyria
  term:
    id: MONDO:0019142
    label: inherited porphyria
parents:
- porphyria
- inborn disorder of porphyrin metabolism
references:
- reference: DOI:10.1146/annurev-med-042921-123602
  title: Update on the Porphyrias
  found_in:
  - Inherited_Porphyria-deep-research-falcon.md
- reference: DOI:10.1182/hematology.2024000663
  title: "Givosiran: a targeted treatment for acute intermittent porphyria"
  found_in:
  - Inherited_Porphyria-deep-research-falcon.md
- reference: DOI:10.1111/liv.16012
  title: Practical recommendations for biochemical and genetic diagnosis of the porphyrias
  found_in:
  - Inherited_Porphyria-deep-research-falcon.md
- reference: DOI:10.3390/life14060689
  title: "Afamelanotide for Treatment of the Protoporphyrias: Impact on Quality of Life and Laboratory Parameters in a US Cohort"
  found_in:
  - Inherited_Porphyria-deep-research-falcon.md
has_subtypes:
- name: Acute Intermittent Porphyria
  display_name: Acute Intermittent Porphyria
  subtype_term:
    preferred_term: acute intermittent porphyria
    term:
      id: MONDO:0008294
      label: acute intermittent porphyria
  description: >-
    Acute hepatic porphyria caused by HMBS deficiency, with neurovisceral
    attacks and no primary blistering photosensitivity.
- name: Porphyria due to ALA Dehydratase Deficiency
  display_name: Porphyria due to ALA Dehydratase Deficiency
  subtype_term:
    preferred_term: porphyria due to ALA dehydratase deficiency
    term:
      id: MONDO:0013000
      label: porphyria due to ALA dehydratase deficiency
  description: >-
    Ultra-rare autosomal recessive acute hepatic porphyria caused by ALAD
    deficiency.
- name: Hereditary Coproporphyria
  display_name: Hereditary Coproporphyria
  subtype_term:
    preferred_term: hereditary coproporphyria
    term:
      id: MONDO:0007369
      label: hereditary coproporphyria
  description: >-
    Acute hepatic porphyria caused by CPOX deficiency, often presenting with
    neurovisceral attacks and sometimes cutaneous lesions.
- name: Variegate Porphyria
  display_name: Variegate Porphyria
  subtype_term:
    preferred_term: variegate porphyria
    term:
      id: MONDO:0008297
      label: variegate porphyria
  description: >-
    Acute hepatic porphyria caused by PPOX deficiency, with neurovisceral
    attacks with or without cutaneous photosensitivity.
- name: Congenital Erythropoietic Porphyria
  display_name: Congenital Erythropoietic Porphyria
  subtype_term:
    preferred_term: congenital erythropoietic porphyria
  description: >-
    UROS-related erythropoietic porphyria characterized by early-onset
    photosensitivity, blistering, anemia, and porphyrin accumulation.
- name: Familial Porphyria Cutanea Tarda
  display_name: Familial Porphyria Cutanea Tarda
  subtype_term:
    preferred_term: familial porphyria cutanea tarda
    term:
      id: MONDO:0008296
      label: familial porphyria cutanea tarda
  description: >-
    Inherited UROD-related porphyria cutanea tarda susceptibility with bullous
    photodermatitis.
- name: Hepatoerythropoietic Porphyria
  display_name: Hepatoerythropoietic Porphyria
  subtype_term:
    preferred_term: hepatoerythropoietic porphyria
    term:
      id: MONDO:0019799
      label: hepatoerythropoietic porphyria
  description: >-
    Very rare biallelic UROD-related chronic hepatic porphyria with severe
    bullous photosensitivity.
- name: Erythropoietic Protoporphyria
  display_name: Erythropoietic Protoporphyria
  subtype_term:
    preferred_term: erythropoietic protoporphyria
    term:
      id: MONDO:0001676
      label: erythropoietic protoporphyria
  description: >-
    Protoporphyrin-accumulating inherited porphyria, usually FECH-related or
    ALAS2-related, with painful cutaneous photosensitivity.
inheritance:
- name: Autosomal dominant inheritance
  inheritance_term:
    preferred_term: Autosomal dominant inheritance
    term:
      id: HP:0000006
      label: Autosomal dominant inheritance
  description: >-
    Several acute hepatic porphyrias, including acute intermittent porphyria,
    hereditary coproporphyria, and variegate porphyria, often follow autosomal
    dominant inheritance with low clinical penetrance.
  evidence:
  - reference: DOI:10.3389/fgene.2024.1374965
    reference_title: "Acute intermittent porphyria: a disease with low penetrance and high heterogeneity"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      AIP is an autosomal dominant disorder characterized by low penetrance and
      a highly heterogenous clinical presentation.
    explanation: >-
      The 2024 AIP review supports autosomal dominant inheritance and low
      penetrance for the major acute hepatic porphyria subtype.
- name: Autosomal recessive inheritance
  inheritance_term:
    preferred_term: Autosomal recessive inheritance
    term:
      id: HP:0000007
      label: Autosomal recessive inheritance
  description: >-
    Some inherited porphyrias, including ALAD porphyria, congenital
    erythropoietic porphyria, and hepatoerythropoietic porphyria, follow
    autosomal recessive inheritance.
- name: X-linked inheritance
  inheritance_term:
    preferred_term: X-linked inheritance
    term:
      id: HP:0001417
      label: X-linked inheritance
  description: >-
    ALAS2-related X-linked protoporphyria is an X-linked inherited
    protoporphyria.
prevalence:
- population: Clinically manifest acute intermittent porphyria
  percentage: 5-10 cases per 100,000 persons
  notes: >-
    AIP is the best quantified inherited porphyria in the Falcon evidence set;
    penetrance is much lower than carrier frequency.
  evidence:
  - reference: DOI:10.3389/fgene.2024.1374965
    reference_title: "Acute intermittent porphyria: a disease with low penetrance and high heterogeneity"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      The estimated prevalence of AIP is 5–10 cases per 100,000 persons, with
      acute attacks manifesting in less than 1% of the at-risk population.
    explanation: >-
      This review provides a population estimate and emphasizes low attack
      penetrance among genetically at-risk individuals.
progression:
- phase: Acute hepatic attack susceptibility
  notes: >-
    Acute hepatic porphyria carriers may remain asymptomatic until physiologic,
    hormonal, medication, fasting, alcohol, tobacco, or illness triggers induce
    hepatic ALAS1 and precursor overproduction.
  evidence:
  - reference: DOI:10.1182/hematology.2024000663
    reference_title: "Givosiran: a targeted treatment for acute intermittent porphyria"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      Pathogenic variants in 1 of 4 enzymes of heme synthesis are necessary for
      the development of AHP, and the onset of acute attacks also requires the
      induction of δ-aminolevulinic acid synthase 1 (ALAS1), the first and
      rate-limiting step of heme synthesis in the liver.
    explanation: >-
      The review describes the gene-plus-ALAS1-induction model for attack
      susceptibility in acute hepatic porphyrias.
- phase: Chronic protoporphyria photosensitivity and liver risk
  notes: >-
    EPP and X-linked protoporphyria cause chronic visible-light intolerance,
    with a minority of EPP patients developing liver dysfunction or terminal
    liver failure from hepatobiliary PPIX elimination.
  evidence:
  - reference: DOI:10.3390/life13041066
    reference_title: Afamelanotide Is Associated with Dose-Dependent Protective Effect from Liver Damage Related to Erythropoietic Protoporphyria
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      In addition to the most prominent symptom of incapacitating phototoxic
      skin reactions, 20% of EPP patients exhibit disturbed liver functioning
      and 4% experience terminal liver failure caused by the hepatobiliary
      elimination of excess PPIX.
    explanation: >-
      This observational EPP study background supports phototoxicity as the
      prominent feature and quantifies liver involvement.
pathophysiology:
- name: Heme Biosynthesis Enzyme Deficiency
  description: >-
    Inherited porphyrias arise when pathogenic variants reduce activity of
    heme-biosynthesis enzymes or alter ALAS2 regulation, creating subtype-
    specific bottlenecks in porphyrin metabolism.
  biological_processes:
  - preferred_term: heme biosynthetic process
    term:
      id: GO:0006783
      label: heme biosynthetic process
    modifier: DECREASED
  - preferred_term: porphyrin-containing compound metabolic process
    term:
      id: GO:0006778
      label: porphyrin-containing compound metabolic process
    modifier: ABNORMAL
  chemical_entities:
  - preferred_term: heme
    term:
      id: CHEBI:30413
      label: heme
    modifier: DECREASED
  evidence:
  - reference: DOI:10.1146/annurev-med-042921-123602
    reference_title: Update on the Porphyrias
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      The porphyrias are a group of rare diseases, each resulting from a defect
      in a different enzymatic step of the heme biosynthetic pathway.
    explanation: >-
      This recent review directly supports the group-level mechanism as
      subtype-specific enzymatic defects in heme biosynthesis.
  downstream:
  - target: Porphyrin Precursor and Porphyrin Accumulation
    causal_link_type: DIRECT
    description: >-
      Impaired pathway flux causes accumulation of pathway intermediates
      upstream of the defective enzymatic step.
    evidence:
    - reference: DOI:10.1146/annurev-med-042921-123602
      reference_title: Update on the Porphyrias
      supports: SUPPORT
      evidence_source: OTHER
      snippet: >-
        They can be broadly divided into two categories, hepatic and
        erythropoietic porphyrias, depending on the primary site of accumulation
        of heme intermediates.
      explanation: >-
        The same review ties porphyria classification to the primary site of
        heme-intermediate accumulation.
  - target: Hepatic ALAS1 Induction and Acute Precursor Overproduction
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    description: >-
      In acute hepatic porphyrias, inherited heme-enzyme defects require
      hepatic ALAS1 induction before acute attacks develop.
    evidence:
    - reference: DOI:10.1182/hematology.2024000663
      reference_title: "Givosiran: a targeted treatment for acute intermittent porphyria"
      supports: SUPPORT
      evidence_source: OTHER
      snippet: >-
        Pathogenic variants in 1 of 4 enzymes of heme synthesis are necessary
        for the development of AHP, and the onset of acute attacks also
        requires the induction of δ-aminolevulinic acid synthase 1 (ALAS1), the
        first and rate-limiting step of heme synthesis in the liver.
      explanation: >-
        This review supports the inherited-enzyme-defect plus hepatic ALAS1
        induction model for acute hepatic porphyria attacks.
  - target: Erythroid Protoporphyrin IX Accumulation
    causal_link_type: DIRECT
    description: >-
      FECH reduction or erythroid ALAS2 gain of function alters the same heme
      biosynthesis pathway and produces protoporphyrin IX accumulation.
    evidence:
    - reference: DOI:10.3390/ph17010031
      reference_title: "Illuminating Dersimelagon: A Novel Agent in the Treatment of Erythropoietic Protoporphyria and X-Linked Protoporphyria"
      supports: SUPPORT
      evidence_source: OTHER
      snippet: >-
        Both of these abnormalities result in the buildup of protoporphyrin IX,
        leading to excruciating light sensitivity and, in a minority of cases,
        potentially fatal liver complications.
      explanation: >-
        This review links FECH/ALAS2 abnormalities in heme biosynthesis to
        protoporphyrin IX accumulation.
  - target: Erythroid Uroporphyrin I Accumulation and Hemolysis
    causal_link_type: DIRECT
    description: >-
      UROS loss reduces uroporphyrinogen synthase activity and creates a CEP
      branch with erythroid porphyrinogen accumulation and erythrocyte damage.
    evidence:
    - reference: PMID:30685241
      reference_title: "Congenital erythropoietic porphyria: Recent advances."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Disease-causing mutations in either gene result in absent or markedly
        reduced UROS enzymatic activity. This in turn leads to the accumulation
        of the non-physiologic and photoreactive porphyrinogens,
        uroporphyrinogen I and coproporphyrinogen I, which damage erythrocytes
        and elicit a phototoxic reaction upon light exposure.
      explanation: >-
        This directly supports the CEP erythroid branch downstream of inherited
        heme-biosynthesis enzyme dysfunction.
- name: Porphyrin Precursor and Porphyrin Accumulation
  description: >-
    Defective heme-biosynthesis flux causes subtype-specific accumulation of
    ALA, porphobilinogen, porphyrins, or protoporphyrin upstream of the blocked
    enzymatic step, generating hepatic, erythropoietic, cutaneous, renal, and
    hepatic complications.
  biological_processes:
  - preferred_term: porphyrin-containing compound metabolic process
    term:
      id: GO:0006778
      label: porphyrin-containing compound metabolic process
    modifier: ABNORMAL
  - preferred_term: heme biosynthetic process
    term:
      id: GO:0006783
      label: heme biosynthetic process
    modifier: ABNORMAL
  chemical_entities:
  - preferred_term: 5-aminolevulinic acid
    term:
      id: CHEBI:17549
      label: 5-aminolevulinic acid
    modifier: INCREASED
  - preferred_term: porphobilinogen
    term:
      id: CHEBI:17381
      label: porphobilinogen
    modifier: INCREASED
  - preferred_term: protoporphyrin
    term:
      id: CHEBI:15430
      label: protoporphyrin
    modifier: INCREASED
  evidence:
  - reference: DOI:10.1146/annurev-med-042921-123602
    reference_title: Update on the Porphyrias
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      They can be broadly divided into two categories, hepatic and
      erythropoietic porphyrias, depending on the primary site of accumulation
      of heme intermediates.
    explanation: >-
      This review supports the shared porphyria mechanism of intermediate
      accumulation, with branch specificity by tissue compartment.
  - reference: DOI:10.1182/hematology.2024000663
    reference_title: "Givosiran: a targeted treatment for acute intermittent porphyria"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      In 2019 the US Food and Drug Administration approved givosiran for AHP
      based on positive results from a phase 3 clinical trial of 94 patients
      with AHP who demonstrated a marked improvement in AHP attacks and a
      substantial decrease in δ-aminolevulinic acid and porphobilinogen, the
      primary disease markers of AHP.
    explanation: >-
      This review identifies ALA and PBG as primary acute hepatic porphyria
      disease markers.
  downstream:
  - target: Neurovisceral Attack Susceptibility
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    description: ALA and PBG accumulation precedes acute porphyria symptoms.
    evidence:
    - reference: DOI:10.3390/jcm13226779
      reference_title: German Real-World Experience of Patients with Diverse Features of Acute Intermittent Porphyria Treated with Givosiran
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Givosiran (siRNA) is an emerging AIP therapy capable of silencing
        delta-aminolevulinic acid synthase-1 (ALAS1) and, in turn, reducing the
        accumulation of delta-aminolevulinic acid (ALA) and porphobilinogen
        (PBG) that precede porphyria symptoms.
      explanation: >-
        The real-world AIP study states that ALA and PBG accumulation precedes
        porphyria symptoms.
  - target: Cutaneous Phototoxicity
    causal_link_type: DIRECT
    description: Photoreactive porphyrin or protoporphyrin accumulation drives light-triggered cutaneous injury.
    evidence:
    - reference: DOI:10.3390/ph17010031
      reference_title: "Illuminating Dersimelagon: A Novel Agent in the Treatment of Erythropoietic Protoporphyria and X-Linked Protoporphyria"
      supports: SUPPORT
      evidence_source: OTHER
      snippet: >-
        Both of these abnormalities result in the buildup of protoporphyrin IX,
        leading to excruciating light sensitivity and, in a minority of cases,
        potentially fatal liver complications.
      explanation: >-
        The protoporphyria review directly links protoporphyrin IX buildup to
        light sensitivity.
  - target: Chronic kidney disease
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    description: ALA and PBG precursor excess is associated with chronic tubulointerstitial kidney injury in AIP.
    evidence:
    - reference: PMID:25830761
      reference_title: High prevalence of and potential mechanisms for chronic kidney disease in patients with acute intermittent porphyria.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Chronic kidney disease occurred in up to 59% of the symptomatic AIP
        patients, with a decline in the glomerular filtration rate of ~1 ml/min
        per 1.73 m(2) annually.
      explanation: >-
        The human AIP cohort supports CKD as a major complication of symptomatic
        acute intermittent porphyria.
    - reference: PMID:25830761
      reference_title: High prevalence of and potential mechanisms for chronic kidney disease in patients with acute intermittent porphyria.
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: >-
        Our experimental data provide evidence that porphyrin precursors promote
        endoplasmic reticulum stress, apoptosis, and epithelial phenotypic
        changes in proximal tubular cells.
      explanation: >-
        The same study provides in vitro support for precursor-mediated tubular
        epithelial injury.
  - target: Abnormality of the liver
    causal_link_type: DIRECT
    description: Excess protoporphyrin eliminated through the hepatobiliary system can cause liver dysfunction.
    evidence:
    - reference: DOI:10.3390/life13041066
      reference_title: Afamelanotide Is Associated with Dose-Dependent Protective Effect from Liver Damage Related to Erythropoietic Protoporphyria
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        In addition to the most prominent symptom of incapacitating phototoxic
        skin reactions, 20% of EPP patients exhibit disturbed liver functioning
        and 4% experience terminal liver failure caused by the hepatobiliary
        elimination of excess PPIX.
      explanation: >-
        This human EPP study connects excess PPIX hepatobiliary elimination to
        liver dysfunction and rare liver failure.
- name: Hepatic ALAS1 Induction and Acute Precursor Overproduction
  description: >-
    In acute hepatic porphyrias, a germline defect in one of four heme-synthesis
    enzymes becomes clinically active when hepatic ALAS1 is induced, increasing
    ALA and PBG production and precipitating neurovisceral symptoms.
  genes:
  - preferred_term: ALAS1
    term:
      id: hgnc:396
      label: ALAS1
    modifier: INCREASED
  cell_types:
  - preferred_term: hepatocyte
    term:
      id: CL:0000182
      label: hepatocyte
  locations:
  - preferred_term: liver
    term:
      id: UBERON:0002107
      label: liver
  biological_processes:
  - preferred_term: heme biosynthetic process
    term:
      id: GO:0006783
      label: heme biosynthetic process
    modifier: INCREASED
  evidence:
  - reference: DOI:10.1182/hematology.2024000663
    reference_title: "Givosiran: a targeted treatment for acute intermittent porphyria"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      The acute hepatic porphyrias (AHPs) are a family of rare genetic diseases
      associated with attacks of abdominal pain, vomiting, weakness, neuropathy,
      and other neurovisceral symptoms.
    explanation: >-
      This review links the acute hepatic porphyria group to neurovisceral
      attacks.
  - reference: DOI:10.1182/hematology.2024000663
    reference_title: "Givosiran: a targeted treatment for acute intermittent porphyria"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      Pathogenic variants in 1 of 4 enzymes of heme synthesis are necessary for
      the development of AHP, and the onset of acute attacks also requires the
      induction of δ-aminolevulinic acid synthase 1 (ALAS1), the first and
      rate-limiting step of heme synthesis in the liver.
    explanation: >-
      This supports the causal chain from inherited enzyme defects to
      liver-specific ALAS1 induction during attacks.
  downstream:
  - target: Neurovisceral Attack Susceptibility
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    description: >-
      ALAS1 induction increases ALA and PBG, the primary biochemical markers
      and toxic precursors of acute hepatic porphyrias.
    evidence:
    - reference: DOI:10.3390/jcm13226779
      reference_title: German Real-World Experience of Patients with Diverse Features of Acute Intermittent Porphyria Treated with Givosiran
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Givosiran (siRNA) is an emerging AIP therapy capable of silencing
        delta-aminolevulinic acid synthase-1 (ALAS1) and, in turn, reducing the
        accumulation of delta-aminolevulinic acid (ALA) and porphobilinogen
        (PBG) that precede porphyria symptoms.
      explanation: >-
        This real-world givosiran study states that reducing ALAS1 reduces ALA
        and PBG accumulation before symptoms.
- name: Erythroid Protoporphyrin IX Accumulation
  description: >-
    EPP and X-linked protoporphyria involve reduced FECH activity or increased
    erythroid ALAS2 activity, producing protoporphyrin IX accumulation in
    erythroid cells and clinically severe visible-light phototoxicity.
  genes:
  - preferred_term: FECH
    term:
      id: hgnc:3647
      label: FECH
    modifier: DECREASED
  - preferred_term: ALAS2
    term:
      id: hgnc:397
      label: ALAS2
    modifier: INCREASED
  cell_types:
  - preferred_term: erythroblast
    term:
      id: CL:0000765
      label: erythroblast
  locations:
  - preferred_term: skin of body
    term:
      id: UBERON:0002097
      label: skin of body
  biological_processes:
  - preferred_term: heme biosynthetic process
    term:
      id: GO:0006783
      label: heme biosynthetic process
    modifier: ABNORMAL
  evidence:
  - reference: DOI:10.3390/ph17010031
    reference_title: "Illuminating Dersimelagon: A Novel Agent in the Treatment of Erythropoietic Protoporphyria and X-Linked Protoporphyria"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      Erythropoietic protoporphyria (EPP) is a genetic disorder stemming from
      reduced ferrochelatase expression, the final enzyme in the pathway of
      heme biosynthesis.
    explanation: >-
      This review supports FECH deficiency at the final heme-biosynthesis step
      as the EPP mechanism.
  - reference: DOI:10.3390/ph17010031
    reference_title: "Illuminating Dersimelagon: A Novel Agent in the Treatment of Erythropoietic Protoporphyria and X-Linked Protoporphyria"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      A closely related condition, X-linked protoporphyria (XLP), bears similar
      clinical features although it arises from the heightened activity of
      δ-aminolevulinic acid synthase 2 (ALAS2), the first and normally
      rate-controlling enzyme in heme biosynthesis in developing red blood
      cells.
    explanation: >-
      This supports ALAS2 gain of function in the erythroid compartment for XLP.
  downstream:
  - target: Cutaneous Phototoxicity
    causal_link_type: DIRECT
    description: >-
      Protoporphyrin IX accumulation causes severe light sensitivity and, in a
      minority, liver complications.
    evidence:
    - reference: DOI:10.3390/ph17010031
      reference_title: "Illuminating Dersimelagon: A Novel Agent in the Treatment of Erythropoietic Protoporphyria and X-Linked Protoporphyria"
      supports: SUPPORT
      evidence_source: OTHER
      snippet: >-
        Both of these abnormalities result in the buildup of protoporphyrin IX,
        leading to excruciating light sensitivity and, in a minority of cases,
        potentially fatal liver complications.
      explanation: >-
        This supports protoporphyrin IX accumulation as the link to
        photosensitivity and liver risk.
  - target: Abnormality of the liver
    causal_link_type: DIRECT
    description: Excess PPIX elimination through hepatobiliary pathways can produce liver dysfunction and rare liver failure.
    evidence:
    - reference: DOI:10.3390/life13041066
      reference_title: Afamelanotide Is Associated with Dose-Dependent Protective Effect from Liver Damage Related to Erythropoietic Protoporphyria
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        In addition to the most prominent symptom of incapacitating phototoxic
        skin reactions, 20% of EPP patients exhibit disturbed liver functioning
        and 4% experience terminal liver failure caused by the hepatobiliary
        elimination of excess PPIX.
      explanation: >-
        Human EPP evidence supports liver dysfunction as a downstream
        complication of excess PPIX elimination.
- name: Erythroid Uroporphyrin I Accumulation and Hemolysis
  description: >-
    Congenital erythropoietic porphyria reflects absent or markedly reduced
    UROS enzymatic activity in erythroid heme synthesis, causing uroporphyrin I
    and coproporphyrin I accumulation, erythrocyte damage, and visible-light
    phototoxicity.
  genes:
  - preferred_term: UROS
    term:
      id: hgnc:12592
      label: UROS
    modifier: DECREASED
  cell_types:
  - preferred_term: erythroblast
    term:
      id: CL:0000765
      label: erythroblast
  - preferred_term: erythrocyte
    term:
      id: CL:0000232
      label: erythrocyte
  biological_processes:
  - preferred_term: heme biosynthetic process
    term:
      id: GO:0006783
      label: heme biosynthetic process
    modifier: DECREASED
  - preferred_term: porphyrin-containing compound metabolic process
    term:
      id: GO:0006778
      label: porphyrin-containing compound metabolic process
    modifier: ABNORMAL
  evidence:
  - reference: PMID:30685241
    reference_title: "Congenital erythropoietic porphyria: Recent advances."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Disease-causing mutations in either gene result in absent or markedly
      reduced UROS enzymatic activity. This in turn leads to the accumulation of
      the non-physiologic and photoreactive porphyrinogens, uroporphyrinogen I
      and coproporphyrinogen I, which damage erythrocytes and elicit a
      phototoxic reaction upon light exposure.
    explanation: >-
      This review directly supports the CEP branch from UROS enzymatic
      deficiency to erythroid porphyrinogen accumulation, hemolysis, and
      phototoxicity.
  downstream:
  - target: Cutaneous Phototoxicity
    causal_link_type: DIRECT
    description: Photoreactive uroporphyrinogen and coproporphyrinogen accumulation elicits visible-light phototoxicity.
    evidence:
    - reference: PMID:30685241
      reference_title: "Congenital erythropoietic porphyria: Recent advances."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        This in turn leads to the accumulation of the non-physiologic and
        photoreactive porphyrinogens, uroporphyrinogen I and coproporphyrinogen
        I, which damage erythrocytes and elicit a phototoxic reaction upon light
        exposure.
      explanation: >-
        This supports CEP phototoxicity downstream of photoreactive
        porphyrinogen accumulation.
  - target: Anemia
    causal_link_type: DIRECT
    description: Porphyrinogen-mediated erythrocyte damage causes chronic hemolytic anemia in CEP.
    evidence:
    - reference: PMID:30685241
      reference_title: "Congenital erythropoietic porphyria: Recent advances."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Chronic transfusion-dependent hemolytic anemia is common and leads to
        bone marrow hyperplasia, which further increases porphyrin production.
      explanation: >-
        The CEP review supports chronic hemolytic anemia downstream of the
        erythroid porphyrin branch.
  - target: Thrombocytopenia
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    description: Severe CEP can include cytopenias beyond hemolytic anemia.
    evidence:
    - reference: PMID:38576642
      reference_title: "Congenital Erythropoietic Porphyria: A Rare Inherited Disorder."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Laboratory investigations demonstrated anemia, leukocytopenia,
        thrombocytopenia, and elevated urine uroporphyrin 1 and coproporphyrin
        1 levels.
      explanation: >-
        This CEP case report supports thrombocytopenia in a patient with
        elevated uroporphyrin and coproporphyrin.
  - target: Abnormal cornea morphology
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - Recurrent visible-light phototoxic injury and scarring of exposed tissues.
    description: Chronic CEP phototoxic injury can involve the cornea.
    evidence:
    - reference: PMID:30685241
      reference_title: "Congenital erythropoietic porphyria: Recent advances."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        In addition, patients have erythrodontia (brownish discoloration of
        teeth) and can develop corneal scarring.
      explanation: >-
        The CEP review supports corneal scarring as a downstream complication.
- name: Neurovisceral Attack Susceptibility
  description: >-
    Acute hepatic porphyria subtypes can develop episodic neurovisceral attacks
    with abdominal pain, vomiting, weakness, neuropathy, and related symptoms.
  biological_processes:
  - preferred_term: heme biosynthetic process
    term:
      id: GO:0006783
      label: heme biosynthetic process
    modifier: ABNORMAL
  evidence:
  - reference: DOI:10.1182/hematology.2024000663
    reference_title: "Givosiran: a targeted treatment for acute intermittent porphyria"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      The acute hepatic porphyrias (AHPs) are a family of rare genetic diseases
      associated with attacks of abdominal pain, vomiting, weakness, neuropathy,
      and other neurovisceral symptoms.
    explanation: >-
      This evidence directly lists the clinical neurovisceral attack surface.
  downstream:
  - target: Abdominal pain
    causal_link_type: DIRECT
    description: Acute hepatic porphyria attacks commonly present with abdominal pain.
    evidence:
    - reference: DOI:10.1182/hematology.2024000663
      reference_title: "Givosiran: a targeted treatment for acute intermittent porphyria"
      supports: SUPPORT
      evidence_source: OTHER
      snippet: >-
        The acute hepatic porphyrias (AHPs) are a family of rare genetic
        diseases associated with attacks of abdominal pain, vomiting, weakness,
        neuropathy, and other neurovisceral symptoms.
      explanation: >-
        The review explicitly lists abdominal pain among acute hepatic
        porphyria attack symptoms.
  - target: Vomiting
    causal_link_type: DIRECT
    description: Acute neurovisceral attacks include gastrointestinal symptoms such as vomiting.
    evidence:
    - reference: DOI:10.1182/hematology.2024000663
      reference_title: "Givosiran: a targeted treatment for acute intermittent porphyria"
      supports: SUPPORT
      evidence_source: OTHER
      snippet: >-
        The acute hepatic porphyrias (AHPs) are a family of rare genetic
        diseases associated with attacks of abdominal pain, vomiting, weakness,
        neuropathy, and other neurovisceral symptoms.
      explanation: >-
        The review explicitly lists vomiting among acute hepatic porphyria
        attack symptoms.
  - target: Peripheral neuropathy
    causal_link_type: DIRECT
    description: Acute hepatic porphyria attacks can include neuropathy.
    evidence:
    - reference: DOI:10.1182/hematology.2024000663
      reference_title: "Givosiran: a targeted treatment for acute intermittent porphyria"
      supports: SUPPORT
      evidence_source: OTHER
      snippet: >-
        The acute hepatic porphyrias (AHPs) are a family of rare genetic
        diseases associated with attacks of abdominal pain, vomiting, weakness,
        neuropathy, and other neurovisceral symptoms.
      explanation: >-
        The review explicitly lists neuropathy among acute hepatic porphyria
        attack symptoms.
- name: Cutaneous Phototoxicity
  description: >-
    Cutaneous and erythropoietic porphyrias cause photosensitivity through
    accumulation of photoreactive porphyrins or protoporphyrin in skin, plasma,
    erythrocytes, or hepatobiliary tissues.
  locations:
  - preferred_term: skin of body
    term:
      id: UBERON:0002097
      label: skin of body
  biological_processes:
  - preferred_term: porphyrin-containing compound metabolic process
    term:
      id: GO:0006778
      label: porphyrin-containing compound metabolic process
    modifier: ABNORMAL
  evidence:
  - reference: DOI:10.3390/life14060689
    reference_title: "Afamelanotide for Treatment of the Protoporphyrias: Impact on Quality of Life and Laboratory Parameters in a US Cohort"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Erythropoietic protoporphyria (EPP) and X-linked protoporphyria (XLP) are
      rare disorders of heme biosynthesis characterized by severe cutaneous
      phototoxicity.
    explanation: >-
      A US clinical cohort directly supports severe cutaneous phototoxicity in
      EPP and XLP.
  downstream:
  - target: Cutaneous photosensitivity
    causal_link_type: DIRECT
    description: Phototoxic porphyrin or protoporphyrin accumulation manifests clinically as severe cutaneous photosensitivity.
    evidence:
    - reference: DOI:10.3390/life14060689
      reference_title: "Afamelanotide for Treatment of the Protoporphyrias: Impact on Quality of Life and Laboratory Parameters in a US Cohort"
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Erythropoietic protoporphyria (EPP) and X-linked protoporphyria (XLP)
        are rare disorders of heme biosynthesis characterized by severe
        cutaneous phototoxicity.
      explanation: >-
        The cohort directly links protoporphyria to severe cutaneous
        phototoxicity, supporting photosensitivity as the clinical endpoint.
phenotypes:
- name: Abdominal pain
  description: >-
    Severe abdominal pain is a core manifestation of acute neurovisceral
    porphyria attacks.
  phenotype_term:
    preferred_term: Abdominal pain
    term:
      id: HP:0002027
      label: Abdominal pain
  subtypes:
  - Acute Intermittent Porphyria
  - Porphyria due to ALA Dehydratase Deficiency
  - Hereditary Coproporphyria
  - Variegate Porphyria
  evidence:
  - reference: DOI:10.1182/hematology.2024000663
    reference_title: "Givosiran: a targeted treatment for acute intermittent porphyria"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      The acute hepatic porphyrias (AHPs) are a family of rare genetic diseases
      associated with attacks of abdominal pain, vomiting, weakness, neuropathy,
      and other neurovisceral symptoms.
    explanation: >-
      Abdominal pain is explicitly listed among acute hepatic porphyria attack
      manifestations.
- name: Vomiting
  description: >-
    Vomiting is part of the gastrointestinal neurovisceral attack phenotype in
    acute hepatic porphyrias.
  phenotype_term:
    preferred_term: Vomiting
    term:
      id: HP:0002013
      label: Vomiting
  subtypes:
  - Acute Intermittent Porphyria
  - Hereditary Coproporphyria
  - Variegate Porphyria
  evidence:
  - reference: DOI:10.1182/hematology.2024000663
    reference_title: "Givosiran: a targeted treatment for acute intermittent porphyria"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      The acute hepatic porphyrias (AHPs) are a family of rare genetic diseases
      associated with attacks of abdominal pain, vomiting, weakness, neuropathy,
      and other neurovisceral symptoms.
    explanation: >-
      Vomiting is explicitly listed among acute hepatic porphyria attack
      manifestations.
- name: Peripheral neuropathy
  description: >-
    Acute porphyria attacks can include peripheral neuropathy.
  phenotype_term:
    preferred_term: Peripheral neuropathy
    term:
      id: HP:0009830
      label: Peripheral neuropathy
  subtypes:
  - Acute Intermittent Porphyria
  - Porphyria due to ALA Dehydratase Deficiency
  - Hereditary Coproporphyria
  - Variegate Porphyria
  evidence:
  - reference: DOI:10.1182/hematology.2024000663
    reference_title: "Givosiran: a targeted treatment for acute intermittent porphyria"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      The acute hepatic porphyrias (AHPs) are a family of rare genetic diseases
      associated with attacks of abdominal pain, vomiting, weakness, neuropathy,
      and other neurovisceral symptoms.
    explanation: >-
      Neuropathy is explicitly listed among acute hepatic porphyria attack
      manifestations.
- name: Chronic kidney disease
  description: >-
    Chronic kidney disease is a major complication reported in symptomatic acute
    intermittent porphyria.
  phenotype_term:
    preferred_term: Chronic kidney disease
    term:
      id: HP:0012622
      label: Chronic kidney disease
  subtypes:
  - Acute Intermittent Porphyria
  evidence:
  - reference: PMID:25830761
    reference_title: High prevalence of and potential mechanisms for chronic kidney disease in patients with acute intermittent porphyria.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Chronic kidney disease occurred in up to 59% of the symptomatic AIP
      patients, with a decline in the glomerular filtration rate of ~1 ml/min per
      1.73 m(2) annually.
    explanation: >-
      This review directly supports chronic kidney disease as a frequent
      complication in symptomatic acute intermittent porphyria.
- name: Cutaneous photosensitivity
  description: >-
    Photosensitivity is a core feature of cutaneous and erythropoietic
    porphyrias and may also occur in variegate porphyria or hereditary
    coproporphyria.
  phenotype_term:
    preferred_term: Cutaneous photosensitivity
    term:
      id: HP:0000992
      label: Cutaneous photosensitivity
  subtypes:
  - Hereditary Coproporphyria
  - Variegate Porphyria
  - Congenital Erythropoietic Porphyria
  - Familial Porphyria Cutanea Tarda
  - Hepatoerythropoietic Porphyria
  - Erythropoietic Protoporphyria
  evidence:
  - reference: DOI:10.3390/life14060689
    reference_title: "Afamelanotide for Treatment of the Protoporphyrias: Impact on Quality of Life and Laboratory Parameters in a US Cohort"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Erythropoietic protoporphyria (EPP) and X-linked protoporphyria (XLP) are
      rare disorders of heme biosynthesis characterized by severe cutaneous
      phototoxicity.
    explanation: >-
      This cohort supports severe cutaneous phototoxicity in protoporphyrias.
- name: Anemia
  description: >-
    Chronic hemolytic anemia is common in congenital erythropoietic porphyria and
    can become transfusion dependent in severe disease.
  phenotype_term:
    preferred_term: Anemia
    term:
      id: HP:0001903
      label: Anemia
  subtypes:
  - Congenital Erythropoietic Porphyria
  evidence:
  - reference: PMID:30685241
    reference_title: "Congenital erythropoietic porphyria: Recent advances."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Chronic transfusion-dependent hemolytic anemia is common and leads to bone
      marrow hyperplasia, which further increases porphyrin production.
    explanation: >-
      This review directly supports anemia as a common CEP manifestation.
- name: Thrombocytopenia
  description: >-
    Thrombocytopenia has been reported in congenital erythropoietic porphyria
    alongside anemia and leukocytopenia.
  phenotype_term:
    preferred_term: Thrombocytopenia
    term:
      id: HP:0001873
      label: Thrombocytopenia
  subtypes:
  - Congenital Erythropoietic Porphyria
  evidence:
  - reference: PMID:38576642
    reference_title: "Congenital Erythropoietic Porphyria: A Rare Inherited Disorder."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Laboratory investigations demonstrated anemia, leukocytopenia,
      thrombocytopenia, and elevated urine uroporphyrin 1 and coproporphyrin 1
      levels.
    explanation: >-
      This case report supports thrombocytopenia as part of the reported CEP
      hematologic phenotype.
- name: Abnormal cornea morphology
  description: >-
    Corneal scarring can occur in congenital erythropoietic porphyria.
  phenotype_term:
    preferred_term: Abnormal cornea morphology
    term:
      id: HP:0000481
      label: Abnormal cornea morphology
  subtypes:
  - Congenital Erythropoietic Porphyria
  evidence:
  - reference: PMID:30685241
    reference_title: "Congenital erythropoietic porphyria: Recent advances."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      In addition, patients have erythrodontia (brownish discoloration of teeth)
      and can develop corneal scarring.
    explanation: >-
      This review directly supports corneal involvement in CEP.
- name: Abnormality of the liver
  description: >-
    EPP can cause liver dysfunction and rarely terminal liver failure because
    excess PPIX is eliminated through the hepatobiliary system.
  phenotype_term:
    preferred_term: Liver dysfunction
    term:
      id: HP:0001392
      label: Abnormality of the liver
  subtypes:
  - Erythropoietic Protoporphyria
  evidence:
  - reference: DOI:10.3390/life13041066
    reference_title: Afamelanotide Is Associated with Dose-Dependent Protective Effect from Liver Damage Related to Erythropoietic Protoporphyria
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      In addition to the most prominent symptom of incapacitating phototoxic
      skin reactions, 20% of EPP patients exhibit disturbed liver functioning
      and 4% experience terminal liver failure caused by the hepatobiliary
      elimination of excess PPIX.
    explanation: >-
      The study directly supports liver involvement in a subset of EPP patients.
biochemical:
- name: Urinary 5-aminolevulinic acid
  presence: INCREASED
  context: >-
    Increased urinary ALA is characteristic of acute hepatic porphyria attacks
    and is reduced by ALAS1-targeted therapy.
  biomarker_term:
    preferred_term: 5-aminolevulinic acid
    term:
      id: CHEBI:17549
      label: 5-aminolevulinic acid
  readouts:
  - target: Hepatic ALAS1 Induction and Acute Precursor Overproduction
    relationship: READOUT_OF
    direction: POSITIVE
    endpoint_context: DIAGNOSTIC
    interpretation: Increased urinary ALA reports hepatic ALAS1-driven precursor overproduction in acute hepatic porphyrias.
    evidence:
    - reference: DOI:10.1182/hematology.2024000663
      reference_title: "Givosiran: a targeted treatment for acute intermittent porphyria"
      supports: SUPPORT
      evidence_source: OTHER
      snippet: >-
        In 2019 the US Food and Drug Administration approved givosiran for AHP
        based on positive results from a phase 3 clinical trial of 94 patients
        with AHP who demonstrated a marked improvement in AHP attacks and a
        substantial decrease in δ-aminolevulinic acid and porphobilinogen, the
        primary disease markers of AHP.
      explanation: >-
        The review identifies ALA as one of the primary AHP disease markers and
        links its reduction to ALAS1-targeted therapy.
  evidence:
  - reference: DOI:10.1182/hematology.2024000663
    reference_title: "Givosiran: a targeted treatment for acute intermittent porphyria"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      In 2019 the US Food and Drug Administration approved givosiran for AHP
      based on positive results from a phase 3 clinical trial of 94 patients
      with AHP who demonstrated a marked improvement in AHP attacks and a
      substantial decrease in δ-aminolevulinic acid and porphobilinogen, the
      primary disease markers of AHP.
    explanation: >-
      The review identifies ALA as one of the primary disease markers of AHP.
- name: Urinary porphobilinogen
  presence: INCREASED
  context: >-
    Increased urinary PBG supports most acute hepatic porphyrias during attacks,
    although ALAD porphyria is an exception because its enzymatic block is
    upstream of PBG formation.
  biomarker_term:
    preferred_term: porphobilinogen
    term:
      id: CHEBI:17381
      label: porphobilinogen
  readouts:
  - target: Hepatic ALAS1 Induction and Acute Precursor Overproduction
    relationship: READOUT_OF
    direction: POSITIVE
    endpoint_context: DIAGNOSTIC
    interpretation: Increased urinary PBG reports acute hepatic porphyria precursor overproduction downstream of ALAS1 induction.
    evidence:
    - reference: DOI:10.1182/hematology.2024000663
      reference_title: "Givosiran: a targeted treatment for acute intermittent porphyria"
      supports: SUPPORT
      evidence_source: OTHER
      snippet: >-
        In 2019 the US Food and Drug Administration approved givosiran for AHP
        based on positive results from a phase 3 clinical trial of 94 patients
        with AHP who demonstrated a marked improvement in AHP attacks and a
        substantial decrease in δ-aminolevulinic acid and porphobilinogen, the
        primary disease markers of AHP.
      explanation: >-
        The review identifies PBG as one of the primary AHP disease markers and
        links its reduction to ALAS1-targeted therapy.
  evidence:
  - reference: DOI:10.1182/hematology.2024000663
    reference_title: "Givosiran: a targeted treatment for acute intermittent porphyria"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      In 2019 the US Food and Drug Administration approved givosiran for AHP
      based on positive results from a phase 3 clinical trial of 94 patients
      with AHP who demonstrated a marked improvement in AHP attacks and a
      substantial decrease in δ-aminolevulinic acid and porphobilinogen, the
      primary disease markers of AHP.
    explanation: >-
      The review identifies PBG as one of the primary disease markers of AHP.
- name: Erythrocyte or plasma protoporphyrin
  presence: INCREASED
  context: >-
    Elevated protoporphyrin is the central biochemical abnormality in EPP and
    X-linked protoporphyria.
  biomarker_term:
    preferred_term: protoporphyrin
    term:
      id: CHEBI:15430
      label: protoporphyrin
  readouts:
  - target: Erythroid Protoporphyrin IX Accumulation
    relationship: READOUT_OF
    direction: POSITIVE
    endpoint_context: DIAGNOSTIC
    interpretation: Increased erythrocyte or plasma protoporphyrin reports protoporphyrin IX accumulation in EPP/XLP.
    evidence:
    - reference: DOI:10.3390/ph17010031
      reference_title: "Illuminating Dersimelagon: A Novel Agent in the Treatment of Erythropoietic Protoporphyria and X-Linked Protoporphyria"
      supports: SUPPORT
      evidence_source: OTHER
      snippet: >-
        Both of these abnormalities result in the buildup of protoporphyrin IX,
        leading to excruciating light sensitivity and, in a minority of cases,
        potentially fatal liver complications.
      explanation: >-
        The review identifies protoporphyrin IX buildup as the biochemical
        abnormality downstream of FECH or ALAS2 defects.
  evidence:
  - reference: DOI:10.3390/ph17010031
    reference_title: "Illuminating Dersimelagon: A Novel Agent in the Treatment of Erythropoietic Protoporphyria and X-Linked Protoporphyria"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      Both of these abnormalities result in the buildup of protoporphyrin IX,
      leading to excruciating light sensitivity and, in a minority of cases,
      potentially fatal liver complications.
    explanation: >-
      The review directly supports protoporphyrin IX buildup in EPP and XLP.
genetic:
- name: Acute hepatic porphyria genes
  gene_term:
    preferred_term: ALAS1
    term:
      id: hgnc:396
      label: ALAS1
  association: Modifier
  features: >-
    Acute hepatic porphyrias require pathogenic variants in one of several
    heme-synthesis enzymes plus hepatic ALAS1 induction for acute attacks.
    Representative subtype genes include HMBS, ALAD, CPOX, and PPOX.
  evidence:
  - reference: DOI:10.1182/hematology.2024000663
    reference_title: "Givosiran: a targeted treatment for acute intermittent porphyria"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      Pathogenic variants in 1 of 4 enzymes of heme synthesis are necessary for
      the development of AHP, and the onset of acute attacks also requires the
      induction of δ-aminolevulinic acid synthase 1 (ALAS1), the first and
      rate-limiting step of heme synthesis in the liver.
    explanation: >-
      This supports the two-part genetic and regulatory requirement for AHP
      attacks.
- name: HMBS pathogenic variants
  gene_term:
    preferred_term: HMBS
    term:
      id: hgnc:4982
      label: HMBS
  association: Causative
  inheritance:
  - name: Autosomal dominant
    description: >-
      HMBS variants cause acute intermittent porphyria with low penetrance.
  features: >-
    HMBS encodes hydroxymethylbilane synthase, a key enzyme in the heme
    biosynthesis pathway.
  evidence:
  - reference: DOI:10.3389/fgene.2024.1374965
    reference_title: "Acute intermittent porphyria: a disease with low penetrance and high heterogeneity"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      Acute intermittent porphyria (AIP) is caused by mutations in the gene
      encoding hydroxymethylbilane synthase (HMBS), a key enzyme in the heme
      biosynthesis pathway.
    explanation: >-
      This directly supports HMBS as the causative AIP gene.
- name: ALAD pathogenic variants
  gene_term:
    preferred_term: ALAD
    term:
      id: hgnc:395
      label: ALAD
  association: Causative
  inheritance:
  - name: Autosomal recessive
    description: >-
      ALAD porphyria is an ultrarare autosomal recessive acute hepatic porphyria.
  features: >-
    Biallelic ALAD variants cause porphyria due to ALA dehydratase deficiency.
  evidence:
  - reference: PMID:33199206
    reference_title: "5-Aminolevulinate dehydratase porphyria: Update on hepatic 5-aminolevulinic acid synthase induction and long-term response to hemin"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      BACKGROUND: 5-Aminolevulinic acid dehydratase (ALAD) porphyria (ADP) is an
      ultrarare autosomal recessive disease, with only eight documented cases,
      all of whom were males.
    explanation: >-
      This review directly supports ALAD porphyria as an autosomal recessive
      inherited porphyria subtype.
- name: CPOX pathogenic variants
  gene_term:
    preferred_term: CPOX
    term:
      id: hgnc:2321
      label: CPOX
  association: Causative
  inheritance:
  - name: Autosomal dominant
    description: >-
      Hereditary coproporphyria is one of the autosomal dominant acute hepatic
      porphyrias.
  features: >-
    Loss-of-function CPOX variants cause hereditary coproporphyria.
  evidence:
  - reference: PMID:30385147
    reference_title: "Acute hepatic porphyrias: Identification of 46 hydroxymethylbilane synthase, 11 coproporphyrinogen oxidase, and 20 protoporphyrinogen oxidase novel mutations"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      AIP, HCP, VP, and ADP each results from loss-of-function (LOF) mutations in
      their disease-causing genes: hydroxymethylbilane synthase (HMBS);
      coproporphyrinogen oxidase (CPOX); protoporphyrinogen oxidase (PPOX), and
      δ-aminolevulinic acid dehydratase (ALAD), respectively.
    explanation: >-
      This review maps HCP to CPOX loss-of-function variants.
- name: PPOX pathogenic variants
  gene_term:
    preferred_term: PPOX
    term:
      id: hgnc:9280
      label: PPOX
  association: Causative
  inheritance:
  - name: Autosomal dominant
    description: >-
      Variegate porphyria is one of the autosomal dominant acute hepatic
      porphyrias.
  features: >-
    Loss-of-function PPOX variants cause variegate porphyria.
  evidence:
  - reference: PMID:30385147
    reference_title: "Acute hepatic porphyrias: Identification of 46 hydroxymethylbilane synthase, 11 coproporphyrinogen oxidase, and 20 protoporphyrinogen oxidase novel mutations"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      AIP, HCP, VP, and ADP each results from loss-of-function (LOF) mutations in
      their disease-causing genes: hydroxymethylbilane synthase (HMBS);
      coproporphyrinogen oxidase (CPOX); protoporphyrinogen oxidase (PPOX), and
      δ-aminolevulinic acid dehydratase (ALAD), respectively.
    explanation: >-
      This review maps VP to PPOX loss-of-function variants.
- name: UROS pathogenic variants
  gene_term:
    preferred_term: UROS
    term:
      id: hgnc:12592
      label: UROS
  association: Causative
  inheritance:
  - name: Autosomal recessive
    description: >-
      Congenital erythropoietic porphyria is most often caused by biallelic UROS
      variants.
  features: >-
    UROS variants reduce uroporphyrinogen III synthase activity and cause
    congenital erythropoietic porphyria.
  evidence:
  - reference: PMID:30685241
    reference_title: "Congenital erythropoietic porphyria: Recent advances."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      CEP is caused by mutations in the uroporphyrinogen synthase (UROS) gene.
    explanation: >-
      This review directly supports UROS as the causative CEP gene.
- name: UROD pathogenic variants
  gene_term:
    preferred_term: UROD
    term:
      id: hgnc:12591
      label: UROD
  association: Causative
  inheritance:
  - name: Autosomal dominant or autosomal recessive
    description: >-
      Heterozygous UROD variants can cause familial porphyria cutanea tarda
      susceptibility, while biallelic UROD variants cause hepatoerythropoietic
      porphyria.
  features: >-
    UROD variants underlie familial porphyria cutanea tarda and
    hepatoerythropoietic porphyria, with inheritance depending on zygosity and
    subtype.
  evidence:
  - reference: PMID:30514647
    reference_title: "Porphyria cutanea tarda and hepatoerythropoietic porphyria: Identification of 19 novel uroporphyrinogen III decarboxylase mutations"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Porphyria Cutanea Tarda (PCT) is a cutaneous porphyria that results from
      the hepatic inhibition of the heme biosynthetic enzyme uroporphyrinogen
      decarboxylase (UROD), and can occur either in the absence or presence of an
      inherited heterozygous UROD mutation (PCT subtypes 1 and 2, respectively).
    explanation: >-
      This molecular diagnostic cohort supports UROD variants in familial/type 2
      porphyria cutanea tarda.
  - reference: PMID:30514647
    reference_title: "Porphyria cutanea tarda and hepatoerythropoietic porphyria: Identification of 19 novel uroporphyrinogen III decarboxylase mutations"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Hepatoerythropoietic Porphyria (HEP) is a rare autosomal recessive disease
      that results from homozygosity or compound heterozygosity for UROD
      mutations and often causes infantile or childhood onset of both
      erythropoietic and cutaneous manifestations.
    explanation: >-
      This molecular diagnostic cohort supports biallelic UROD variants as
      causative for hepatoerythropoietic porphyria.
- name: Protoporphyria genes
  gene_term:
    preferred_term: FECH
    term:
      id: hgnc:3647
      label: FECH
  association: Causative
  inheritance:
  - name: Autosomal recessive or X-linked
    description: >-
      FECH-related EPP is typically autosomal; ALAS2-related XLP is X-linked.
  features: >-
    Reduced FECH expression and increased ALAS2 activity both produce PPIX
    accumulation and protoporphyria.
  evidence:
  - reference: DOI:10.3390/ph17010031
    reference_title: "Illuminating Dersimelagon: A Novel Agent in the Treatment of Erythropoietic Protoporphyria and X-Linked Protoporphyria"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      Erythropoietic protoporphyria (EPP) is a genetic disorder stemming from
      reduced ferrochelatase expression, the final enzyme in the pathway of
      heme biosynthesis.
    explanation: >-
      This directly supports FECH reduction in EPP.
  - reference: DOI:10.3390/ph17010031
    reference_title: "Illuminating Dersimelagon: A Novel Agent in the Treatment of Erythropoietic Protoporphyria and X-Linked Protoporphyria"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      A closely related condition, X-linked protoporphyria (XLP), bears similar
      clinical features although it arises from the heightened activity of
      δ-aminolevulinic acid synthase 2 (ALAS2), the first and normally
      rate-controlling enzyme in heme biosynthesis in developing red blood
      cells.
    explanation: >-
      This directly supports increased ALAS2 activity as the XLP mechanism.
diagnosis:
- name: Biochemical porphyria testing
  diagnosis_term:
    preferred_term: diagnostic procedure
    term:
      id: MAXO:0000003
      label: diagnostic procedure
  description: >-
    Symptomatic patients require biochemical testing of heme precursors and
    porphyrins in urine, feces, and blood before genomic confirmation.
  results: >-
    Typical heme-precursor or porphyrin patterns classify acute, cutaneous, and
    erythropoietic porphyria presentations.
  evidence:
  - reference: DOI:10.1111/liv.16012
    reference_title: Practical recommendations for biochemical and genetic diagnosis of the porphyrias
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      To diagnose a patient with porphyria requires appropriate biochemical
      investigations, as clinical features alone are not specific enough.
    explanation: >-
      This diagnostic recommendations review supports biochemical testing as
      required because clinical features are nonspecific.
  - reference: DOI:10.1111/liv.16012
    reference_title: Practical recommendations for biochemical and genetic diagnosis of the porphyrias
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      To diagnose porphyria in a currently symptomatic patient requires
      analysis of biochemical markers to demonstrate typical patterns of haem
      precursors in urine, faeces and blood.
    explanation: >-
      This directly supports urine, feces, and blood biochemical testing.
- name: Urinary ALA and porphobilinogen measurement
  diagnosis_term:
    preferred_term: urine chemistry measurement
    term:
      id: MAXO:0000789
      label: urine chemistry measurement
  description: >-
    Urine ALA and PBG testing during symptoms is the initial biochemical screen
    for acute hepatic porphyria.
  results: Increased ALA with or without increased PBG helps classify acute porphyria subtype.
  evidence:
  - reference: DOI:10.1182/hematology.2024000663
    reference_title: "Givosiran: a targeted treatment for acute intermittent porphyria"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      In 2019 the US Food and Drug Administration approved givosiran for AHP
      based on positive results from a phase 3 clinical trial of 94 patients
      with AHP who demonstrated a marked improvement in AHP attacks and a
      substantial decrease in δ-aminolevulinic acid and porphobilinogen, the
      primary disease markers of AHP.
    explanation: >-
      This supports ALA and PBG as primary acute hepatic porphyria biomarkers.
- name: Molecular genetic testing
  diagnosis_term:
    preferred_term: genetic testing
    term:
      id: MAXO:0000127
      label: genetic testing
  description: >-
    Genetic testing confirms the causal heme-biosynthesis gene and inheritance
    pattern after biochemical testing indicates a porphyria subtype; in
    symptomatic patients, increased biochemical markers should precede genomic
    testing.
  results: Pathogenic variants in a porphyria gene establish the inherited subtype.
  evidence:
  - reference: DOI:10.1111/liv.16012
    reference_title: Practical recommendations for biochemical and genetic diagnosis of the porphyrias
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      The use of genomic sequencing in diagnostic pathways for porphyrias
      requires careful consideration, and the demonstration of increased
      porphyrin‐related markers is necessary prior to genomic testing in
      symptomatic patients.
    explanation: >-
      This supports genomic testing as confirmatory and marker-guided in
      symptomatic patients.
treatments:
- name: Trigger avoidance and supportive care
  description: >-
    Avoidance of unsafe medications, fasting, alcohol, tobacco, and other
    attack triggers is foundational for acute hepatic porphyrias; supportive
    care is needed during attacks.
  treatment_term:
    preferred_term: supportive care
    term:
      id: MAXO:0000950
      label: supportive care
  target_phenotypes:
  - preferred_term: Abdominal pain
    term:
      id: HP:0002027
      label: Abdominal pain
  evidence:
  - reference: DOI:10.3390/jcm13226779
    reference_title: German Real-World Experience of Patients with Diverse Features of Acute Intermittent Porphyria Treated with Givosiran
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The elimination of precipitating factors, hemin therapy, and pain relief
      are strategies used to treat porphyria symptoms, but are often reserved
      for patients suffering recurrent, acute attacks.
    explanation: >-
      This real-world AIP study background supports trigger elimination and
      supportive symptom-directed care for acute attacks.
- name: Hemin or heme arginate pharmacotherapy
  description: >-
    Intravenous hemin or heme arginate is used for severe acute hepatic
    porphyria attacks to repress hepatic ALAS1 and lower precursor production.
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: hemin
      term:
        id: CHEBI:50385
        label: hemin
  target_mechanisms:
  - target: Hepatic ALAS1 Induction and Acute Precursor Overproduction
    treatment_effect: INHIBITS
    description: >-
      Heme therapy is used to suppress hepatic ALAS1-driven precursor
      overproduction during acute attacks.
  evidence:
  - reference: DOI:10.3390/jcm13226779
    reference_title: German Real-World Experience of Patients with Diverse Features of Acute Intermittent Porphyria Treated with Givosiran
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The elimination of precipitating factors, hemin therapy, and pain relief
      are strategies used to treat porphyria symptoms, but are often reserved
      for patients suffering recurrent, acute attacks.
    explanation: >-
      The real-world AIP study background supports hemin and supportive
      symptom-directed care for acute/recurrent attacks.
- name: Givosiran pharmacotherapy
  description: >-
    Givosiran is an ALAS1-targeted siRNA therapy for acute hepatic porphyria
    that reduces ALA/PBG and lowers attack burden, with monitoring for liver,
    renal, injection-site, and homocysteine-related adverse effects.
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: givosiran
      term:
        id: NCIT:C146805
        label: Givosiran
  target_mechanisms:
  - target: Hepatic ALAS1 Induction and Acute Precursor Overproduction
    treatment_effect: INHIBITS
    description: >-
      Givosiran inhibits hepatic ALAS1 mRNA to reduce ALA and PBG accumulation.
    evidence:
    - reference: DOI:10.1182/hematology.2024000663
      reference_title: "Givosiran: a targeted treatment for acute intermittent porphyria"
      supports: SUPPORT
      evidence_source: OTHER
      snippet: >-
        Givosiran is an RNA interference medication that inhibits hepatic ALAS1
        and was designed to treat AHP.
      explanation: >-
        This review directly states givosiran's ALAS1-targeted mechanism.
  evidence:
  - reference: DOI:10.1186/s13023-024-03284-w
    reference_title: "Long-term follow-up of givosiran treatment in patients with acute intermittent porphyria from a phase 1/2, 48-month open-label extension study"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Givosiran therapy reduced annualized rates of porphyria attacks and hemin
      use by 97% and 96%, respectively.
    explanation: >-
      The 48-month open-label extension provides direct clinical evidence for
      reduced attacks and hemin use.
  - reference: DOI:10.3390/jcm13226779
    reference_title: German Real-World Experience of Patients with Diverse Features of Acute Intermittent Porphyria Treated with Givosiran
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Givosiran is effective in preventing severe acute attacks and reducing the
      chronic health burden in patients with acute intermittent porphyria.
    explanation: >-
      The German real-world cohort supports effectiveness in patients with
      acute intermittent porphyria.
- name: Bone marrow transplantation for severe CEP
  description: >-
    Bone marrow or hematopoietic stem cell transplantation can be curative in
    severe congenital erythropoietic porphyria.
  treatment_term:
    preferred_term: bone marrow transplantation
    term:
      id: MAXO:0010030
      label: bone marrow transplantation
  target_phenotypes:
  - preferred_term: Anemia
    term:
      id: HP:0001903
      label: Anemia
  - preferred_term: Cutaneous photosensitivity
    term:
      id: HP:0000992
      label: Cutaneous photosensitivity
  target_mechanisms:
  - target: Erythroid Uroporphyrin I Accumulation and Hemolysis
    treatment_effect: RESTORES
    description: >-
      Hematopoietic stem cell or bone marrow transplantation can replace the
      diseased erythropoietic compartment and is considered curative in severe
      CEP.
    evidence:
    - reference: PMID:38576642
      reference_title: "Congenital Erythropoietic Porphyria: A Rare Inherited Disorder."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Stem cell transplantation remains the sole curative therapy for this
        exceedingly rare condition.
      explanation: >-
        The CEP case report and review supports transplantation as a curative
        intervention for the erythropoietic disease mechanism.
  evidence:
  - reference: PMID:30685241
    reference_title: "Congenital erythropoietic porphyria: Recent advances."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      In severe transfection-dependent cases, bone marrow or hematopoietic stem
      cell transplantation has been performed, which is curative.
    explanation: >-
      This review supports transplantation as curative therapy for severe CEP.
  - reference: PMID:38576642
    reference_title: "Congenital Erythropoietic Porphyria: A Rare Inherited Disorder."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Stem cell transplantation remains the sole curative therapy for this
      exceedingly rare condition.
    explanation: >-
      This case report and review supports stem cell transplantation as curative
      therapy for CEP.
- name: Photoprotection
  description: >-
    Sunlight and visible-light avoidance, protective clothing, and related
    measures reduce cutaneous phototoxic injury in photosensitive porphyrias.
  treatment_term:
    preferred_term: supportive care
    term:
      id: MAXO:0000950
      label: supportive care
  target_phenotypes:
  - preferred_term: Cutaneous photosensitivity
    term:
      id: HP:0000992
      label: Cutaneous photosensitivity
  evidence:
  - reference: DOI:10.3390/ph17010031
    reference_title: "Illuminating Dersimelagon: A Novel Agent in the Treatment of Erythropoietic Protoporphyria and X-Linked Protoporphyria"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      Traditionally, managing EPP and XLP involved sun avoidance.
    explanation: >-
      This review supports sun avoidance as traditional protoporphyria
      management.
- name: Afamelanotide pharmacotherapy
  description: >-
    Afamelanotide is an alpha-melanocyte-stimulating hormone analogue and
    approved protoporphyria treatment that increases light tolerance and
    improves quality of life.
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: afamelanotide
      term:
        id: CHEBI:136034
        label: afamelanotide
  target_mechanisms:
  - target: Cutaneous Phototoxicity
    treatment_effect: MODULATES
    description: >-
      Afamelanotide improves light tolerance in EPP and XLP without correcting
      the underlying protoporphyrin accumulation.
  evidence:
  - reference: DOI:10.3390/life14060689
    reference_title: "Afamelanotide for Treatment of the Protoporphyrias: Impact on Quality of Life and Laboratory Parameters in a US Cohort"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Afamelanotide, an α-melanocyte-stimulating hormone analogue, is the
      only approved treatment for protoporphyria and leads to increased light
      tolerance and improved quality of life (QoL).
    explanation: >-
      The US cohort directly supports afamelanotide as approved therapy that
      improves light tolerance and quality of life.
  - reference: DOI:10.3390/life14060689
    reference_title: "Afamelanotide for Treatment of the Protoporphyrias: Impact on Quality of Life and Laboratory Parameters in a US Cohort"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Among the patients who received ≥2 implants, the median time to symptom
      onset following sunlight exposure was 12.5 min (IQR, 5–20) prior to the
      initiation of afamelanotide and 120 min (IQR, 60–240) after treatment (p
      < 0.001).
    explanation: >-
      This provides direct clinical evidence for improved sunlight tolerance.
- name: Dersimelagon pharmacotherapy
  description: >-
    Dersimelagon is an investigational oral MC1R agonist being developed for
    EPP and X-linked protoporphyria.
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: dersimelagon
      term:
        id: NCIT:C166490
        label: Dersimelagon
  target_mechanisms:
  - target: Cutaneous Phototoxicity
    treatment_effect: MODULATES
    description: >-
      MC1R agonism is intended to prevent phototoxicity and related pain in EPP
      and XLP.
  evidence:
  - reference: DOI:10.3390/ph17010031
    reference_title: "Illuminating Dersimelagon: A Novel Agent in the Treatment of Erythropoietic Protoporphyria and X-Linked Protoporphyria"
    supports: PARTIAL
    evidence_source: OTHER
    snippet: >-
      However, the emergence of innovative therapies, such as dersimelagon, is
      reshaping the therapeutic landscape for these conditions.
    explanation: >-
      The review supports dersimelagon as an emerging therapy; marked PARTIAL
      because this abstract-level evidence does not establish final clinical
      approval or long-term outcomes.
📚

References & Deep Research

References

4
DOI:10.1146/annurev-med-042921-123602
Update on the Porphyrias
No top-level findings curated for this source.
DOI:10.1182/hematology.2024000663
Givosiran: a targeted treatment for acute intermittent porphyria
No top-level findings curated for this source.
DOI:10.1111/liv.16012
Practical recommendations for biochemical and genetic diagnosis of the porphyrias
No top-level findings curated for this source.
DOI:10.3390/life14060689
Afamelanotide for Treatment of the Protoporphyrias: Impact on Quality of Life and Laboratory Parameters in a US Cohort
No top-level findings curated for this source.

Deep Research

1
Falcon ▸
Disease Characteristics Research Template
Edison Scientific Literature 44 citations 2026-05-10T11:24:56.960893

Question: You are an expert researcher providing comprehensive, well-cited information.

Provide detailed information focusing on: 1. Key concepts and definitions with current understanding 2. Recent developments and latest research (prioritize 2023-2024 sources) 3. Current applications and real-world implementations 4. Expert opinions and analysis from authoritative sources 5. Relevant statistics and data from recent studies

Format as a comprehensive research report with proper citations. Include URLs and publication dates where available. Always prioritize recent, authoritative sources and provide specific citations for all major claims.

Disease Characteristics Research Template

Target Disease

  • Disease Name: Inherited Porphyria
  • MONDO ID: (if available)
  • Category: Mendelian

Research Objectives

Please provide a comprehensive research report on Inherited Porphyria covering all of the disease characteristics listed below. This report will be used to populate a disease knowledge base entry. Be thorough and cite primary literature (PMID preferred) for all claims.

For each section, suggested databases/resources are listed. These are the first places you should search for information on each topic.

1. Disease Information

Search first: OMIM, Orphanet, ICD-10/ICD-11, MeSH, PubMed

  • What is the disease? Provide a concise overview.
  • What are the key identifiers? (OMIM, Orphanet, ICD-10/ICD-11, MeSH, Mondo)
  • What are the common synonyms and alternative names?
  • Is the information derived from individual patients (e.g., EHR) or aggregated disease-level resources?

2. Etiology

  • Disease Causal Factors: What are the primary causes? (genetic, environmental, infectious, mechanistic)
  • Risk Factors:

    Search first: PubMed, Cochrane Library, UpToDate, clinical guidelines, ClinVar, ClinGen, GWAS Catalog, PheGenI, CTD, CDC, WHO, epidemiological databases

  • Genetic risk factors (causal variants, susceptibility loci, modifier genes)
  • Environmental risk factors (toxins, lifestyle, occupational exposures, age, sex, family history)
  • Protective Factors:

    Search first: PubMed, Cochrane Library, clinical trial databases, GWAS Catalog, gnomAD, WHO, CDC, nutrition databases

  • Genetic protective factors (protective variants, modifier alleles)
  • Environmental protective factors (diet, lifestyle, exposures that reduce risk)
  • Gene-Environment Interactions: How do genetic and environmental factors interact to influence disease?

    Search first: CTD, PubMed, PheGenI, GxE databases

3. Phenotypes

Search first: HPO (Human Phenotype Ontology), OMIM, Orphanet, PubMed, clinicaltrials.gov, MedDRA, SNOMED CT, DECIPHER, LOINC

For each phenotype, provide: - Phenotype type: symptoms, clinical signs, physical manifestations, behavioral changes, or laboratory abnormalities

For symptoms/signs: HPO, OMIM, Orphanet, PubMed For behavioral changes: HPO, DSM, RDoC (Research Domain Criteria), PubMed For laboratory abnormalities: LOINC, SNOMED CT, LabTests Online, PubMed - Phenotype characteristics: Search first: OMIM, Orphanet, HPO, PubMed - Age of symptom onset (neonatal, childhood, adult-onset, late-onset) - Symptom severity (mild, moderate, severe, variable) - Symptom progression (stable, progressive, episodic, fluctuating) - Frequency among affected individuals (percentage or qualitative) - Quality of life impact: Effects on daily functioning and well-being (per-phenotype when possible) Search first: EQ-5D database, SF-36, WHO QOL databases, PubMed - Suggest HPO (Human Phenotype Ontology) terms for each phenotype

4. Genetic/Molecular Information

  • Causal Genes: Gene mutations or chromosomal abnormalities responsible for disease (gene symbols, OMIM IDs)

    Search first: OMIM, ClinVar, HGMD, Ensembl, NCBI Gene

  • Pathogenic Variants:
  • Affected genes (gene symbols, HGNC IDs) > Search first: OMIM, NCBI Gene, Ensembl, HGNC, UniProt, GeneCards
  • Variant classification (pathogenic, likely pathogenic, VUS per ACMG/AMP guidelines) > Search first: ClinVar, ClinGen, ACMG/AMP guidelines, VarSome
  • Variant type/class (missense, frameshift, nonsense, splice-site, structural)
  • Allele frequency in population databases > Search first: gnomAD, 1000 Genomes, ExAC, TOPMed, dbSNP
  • Somatic vs germline origin > Search first: COSMIC (somatic), ClinVar, ICGC, TCGA
  • Functional consequences (loss of function, gain of function, dominant negative)
  • Modifier Genes: Genes that modify disease severity or expression
  • Epigenetic Information: DNA methylation, histone modifications, chromatin changes affecting disease

    Search first: ENCODE, Roadmap Epigenomics, MethBase, DiseaseMeth

  • Chromosomal Abnormalities: Large-scale genetic changes (aneuploidy, translocations, inversions)

    Search first: DECIPHER, ClinVar, ECARUCA, UCSC Genome Browser

5. Environmental Information

  • Environmental Factors: Non-genetic contributing factors (toxins, radiation, pollution, occupational exposure)

    Search first: CTD (Comparative Toxicogenomics Database), TOXNET, PubMed, EPA databases

  • Lifestyle Factors: Behavioral factors (smoking, diet, exercise, alcohol consumption)

    Search first: CDC databases, WHO, PubMed, NHANES

  • Infectious Agents: If applicable, pathogens causing or triggering disease (bacteria, viruses, fungi, parasites)

    Search first: NCBI Taxonomy, ViPR, BV-BRC, MicrobeDB, GIDEON

6. Mechanism / Pathophysiology

  • Molecular Pathways: Specific signaling cascades or biochemical pathways involved (Wnt, MAPK, mTOR, PI3K-AKT, etc.)

    Search first: KEGG, Reactome, WikiPathways, PathBank, BioCyc

  • Cellular Processes: Cell-level mechanisms (apoptosis, autophagy, cell cycle dysregulation, inflammation, etc.)

    Search first: Gene Ontology (GO), Reactome, KEGG, PubMed

  • Protein Dysfunction: How protein structure or function is altered (misfolding, aggregation, loss of function, gain of function)

    Search first: UniProt, PDB (Protein Data Bank), InterPro, Pfam, AlphaFold

  • Metabolic Changes: Alterations in metabolic processes (energy metabolism, lipid metabolism, amino acid metabolism)

    Search first: KEGG, BioCyc, HMDB (Human Metabolome Database), BRENDA

  • Immune System Involvement: Role of immune response (autoimmunity, immunodeficiency, chronic inflammation)

    Search first: ImmPort, Immunome Database, IEDB, Gene Ontology

  • Tissue Damage Mechanisms: How tissues/ are injured (oxidative stress, ischemia, fibrosis, necrosis)

    Search first: PubMed, Gene Ontology, Reactome

  • Biochemical Abnormalities: Specific molecular defects (enzyme deficiencies, receptor dysfunction, ion channel defects)

    Search first: BRENDA, UniProt, KEGG, OMIM, PubMed

  • Epigenetic Changes: DNA methylation, histone modifications affecting gene expression in disease

    Search first: ENCODE, Roadmap Epigenomics, MethBase, DiseaseMeth

  • Molecular Profiling (if available):
  • Transcriptomics/gene expression changes > Search first: GEO (Gene Expression Omnibus), ArrayExpress, GTEx, Human Cell Atlas, SRA
  • Proteomics findings > Search first: PRIDE, ProteomeXchange, Human Protein Atlas, STRING, BioGRID
  • Metabolomics signatures > Search first: MetaboLights, Metabolomics Workbench, HMDB, METLIN
  • Lipidomics alterations > Search first: LIPID MAPS, SwissLipids, LipidHome, Metabolomics Workbench
  • Genomic structural features > Search first: UCSC Genome Browser, Ensembl, NCBI, dbVar, DGV
  • Advanced Technologies (if applicable):
  • Single-cell analysis findings (cell-type specific mechanisms, cellular heterogeneity) > Search first: Human Cell Atlas, Single Cell Portal, GEO, CELLxGENE
  • Spatial transcriptomics findings > Search first: GEO, Spatial Research, Vizgen, 10x Genomics data
  • Multi-omics integration results > Search first: TCGA, ICGC, cBioPortal, LinkedOmics, PubMed
  • Functional genomics screens (CRISPR, RNAi) > Search first: DepMap, GenomeRNAi, PubMed, BioGRID ORCS

For each mechanism, describe: - The causal chain from initial trigger to clinical manifestation - Which mechanisms are upstream vs downstream - What cell types and biological processes are involved - Suggest GO terms for biological processes and CL terms for cell types

7. Anatomical Structures Affected

  • Organ Level:
  • Primary organs directly affected
  • Secondary organ involvement (complications, secondary effects)
  • Body systems involved (cardiovascular, nervous, digestive, respiratory, endocrine, etc.)

    Search first: Uberon, FMA (Foundational Model of Anatomy), OMIM, HPO, ICD-11, MeSH, SNOMED CT

  • Tissue and Cell Level:
  • Specific tissue types affected (epithelial, connective, muscle, nervous)
  • Specific cell populations targeted (with Cell Ontology terms)

    Search first: Uberon, Human Protein Atlas, Cell Ontology, Human Cell Atlas, CellMarker, PanglaoDB

  • Subcellular Level:
  • Cellular compartments involved (mitochondria, nucleus, ER, lysosomes) (with GO Cellular Component terms)

    Search first: Gene Ontology (Cellular Component), UniProt, Human Protein Atlas

  • Localization:
  • Specific anatomical sites (with UBERON terms) > Search first: FMA, Uberon, NeuroNames (for brain), SNOMED CT
  • Lateralization (unilateral, bilateral, asymmetric) > Search first: HPO, clinical literature, imaging databases

8. Temporal Development

  • Onset:
  • Typical age of onset (congenital, pediatric, adult, geriatric)
  • Onset pattern (acute, subacute, chronic, insidious)

    Search first: OMIM, Orphanet, HPO, PubMed

  • Progression:
  • Disease stages (early, intermediate, advanced, end-stage) > Search first: Cancer Staging Manual (AJCC), WHO classifications, PubMed
  • Progression rate (rapid, slow, variable)
  • Disease course pattern (episodic, relapsing-remitting, progressive, stable)
  • Disease duration (self-limited, chronic lifelong)

    Search first: Disease registries, longitudinal cohort databases, natural history studies, PubMed, Orphanet, OMIM

  • Patterns:
  • Remission patterns (spontaneous, treatment-induced) > Search first: Clinical trial databases, disease registries, PubMed
  • Critical periods (time windows of vulnerability or opportunity for intervention) > Search first: PubMed, developmental biology databases, clinical guidelines

9. Inheritance and Population

  • Epidemiology:
  • Prevalence (cases per 100,000 at given time)
  • Incidence (new cases per 100,000 per year)

    Search first: Orphanet, CDC, WHO, GBD (Global Burden of Disease), national registries, SEER, disease registries

  • For Genetic Etiology:
  • Inheritance pattern (AD, AR, X-linked, mitochondrial, multifactorial, polygenic) > Search first: OMIM, Orphanet, ClinVar, GTR (Genetic Testing Registry)
  • Penetrance (complete, incomplete, age-dependent) > Search first: ClinVar, OMIM, PubMed, ClinGen
  • Expressivity (variable, consistent) > Search first: OMIM, ClinVar, PubMed
  • Genetic anticipation (increasing severity in successive generations) > Search first: OMIM, PubMed (especially for repeat expansion disorders)
  • Germline mosaicism > Search first: ClinVar, OMIM, genetic counseling literature, PubMed
  • Founder effects (population-specific mutations) > Search first: gnomAD, population genetics databases, PubMed
  • Consanguinity role > Search first: OMIM, population studies, genetic counseling resources
  • Carrier frequency > Search first: gnomAD, carrier screening databases, GeneReviews, GTR
  • Population Demographics:
  • Affected populations (ethnic or demographic groups with higher prevalence) > Search first: gnomAD, 1000 Genomes, PAGE Study, PubMed, population registries
  • Geographic distribution (endemic areas, regional variation) > Search first: WHO, CDC, GBD, Orphanet, geographic epidemiology databases
  • Geographic distribution of specific variants
  • Sex ratio (male:female) > Search first: Disease registries, OMIM, PubMed, epidemiological databases
  • Age distribution of affected individuals > Search first: CDC, disease registries, SEER, Orphanet

10. Diagnostics

  • Clinical Tests:
  • Laboratory tests (blood, urine, tissue chemistry, specific enzyme assays) > Search first: LOINC, LabTests Online, PubMed
  • Biomarkers (proteins, metabolites, genetic markers, circulating biomarkers) > Search first: FDA Biomarker List, BEST (Biomarkers, EndpointS, and other Tools), PubMed
  • Imaging studies (X-ray, CT, MRI, PET, ultrasound) > Search first: RadLex, DICOM, Radiopaedia, imaging databases
  • Functional tests (pulmonary function, cardiac stress tests) > Search first: LOINC, clinical guidelines, PubMed
  • Electrophysiology (EEG, EMG, ECG, nerve conduction studies) > Search first: LOINC, clinical neurophysiology databases, PubMed
  • Biopsy findings (histopathology, immunohistochemistry) > Search first: SNOMED CT, College of American Pathologists resources, PubMed
  • Pathology findings (microscopic examination) > Search first: SNOMED CT, Digital Pathology databases, PubMed
  • Genetic Testing:

    Search first: GTR (Genetic Testing Registry), GeneReviews, ClinGen

  • Overview of recommended genetic testing approach
  • Whole genome sequencing (WGS) utility > Search first: GTR, ClinVar, GEL (Genomics England), gnomAD
  • Whole exome sequencing (WES) utility > Search first: GTR, ClinVar, OMIM, GeneMatcher
  • Gene panels (which panels, which genes) > Search first: GTR, ClinVar, laboratory-specific databases
  • Single gene testing > Search first: GTR, ClinVar, OMIM, GeneReviews
  • Chromosomal microarray (CMA) > Search first: DECIPHER, ClinVar, dbVar, ECARUCA
  • Karyotyping > Search first: Chromosome Abnormality Database, ClinVar, cytogenetics resources
  • FISH > Search first: ClinVar, cytogenetics databases, PubMed
  • Mitochondrial DNA testing > Search first: MITOMAP, MSeqDR, ClinVar, GTR
  • Repeat expansion testing > Search first: GTR, ClinVar, repeat expansion databases, PubMed
  • Omics-Based Diagnostics (if applicable):
  • RNA sequencing / transcriptomics > Search first: GEO, ArrayExpress, GTEx, RNA-seq databases
  • Proteomics > Search first: PRIDE, ProteomeXchange, FDA Biomarker database
  • Metabolomics > Search first: MetaboLights, Metabolomics Workbench, HMDB
  • Epigenomics > Search first: GEO, ENCODE, Roadmap Epigenomics, MethBase
  • Liquid biopsy > Search first: COSMIC, ClinVar, liquid biopsy databases, PubMed
  • Clinical Criteria:
  • Standardized diagnostic criteria (DSM, ICD, society guidelines) > Search first: DSM-5, ICD-11, clinical society guidelines, UpToDate
  • Differential diagnosis (other conditions to rule out, with distinguishing features) > Search first: DynaMed, UpToDate, clinical decision support systems
  • Screening:
  • Screening methods for asymptomatic individuals (newborn screening, carrier screening, cascade screening) > Search first: ACMG recommendations, CDC newborn screening, GTR

11. Outcome/Prognosis

  • Survival and Mortality:
  • Survival rate (5-year, 10-year, overall) > Search first: SEER, cancer registries, disease-specific registries, PubMed
  • Life expectancy (with and without treatment if applicable) > Search first: Orphanet, disease registries, actuarial databases, PubMed
  • Mortality rate > Search first: CDC, WHO, GBD, national mortality databases
  • Disease-specific mortality (deaths directly attributable to disease) > Search first: Disease registries, CDC Wonder, GBD, PubMed
  • Morbidity and Function:
  • Morbidity (disease-related disability and health impacts) > Search first: GBD, WHO, disability databases, PubMed
  • Disability outcomes (long-term functional impairments) > Search first: ICF (International Classification of Functioning), disability registries
  • Quality of life measures (EQ-5D, SF-36, PROMIS, disease-specific tools) > Search first: EQ-5D database, SF-36, PROMIS, PubMed
  • Disease Course:
  • Complications (secondary problems: infections, organ failure, etc.) > Search first: ICD codes, disease registries, clinical databases, PubMed
  • Recovery potential (likelihood and extent of recovery, with vs without treatment) > Search first: Natural history studies, rehabilitation databases, PubMed
  • Prediction:
  • Prognostic factors (age, disease severity, biomarkers, treatment response) > Search first: Prognostic models databases, clinical calculators, PubMed
  • Prognostic biomarkers (molecular markers predicting disease course) > Search first: FDA Biomarker database, PubMed, cancer prognostic databases

12. Treatment

  • Pharmacotherapy:
  • Pharmacological treatments (drug names, drug classes, mechanisms of action) > Search first: DrugBank, RxNorm, ATC classification, DailyMed, FDA databases
  • Pharmacogenomics (how genetic variants affect drug metabolism, efficacy, toxicity) > Search first: PharmGKB, CPIC (Clinical Pharmacogenetics), FDA Table of PGx Biomarkers
  • Advanced Therapeutics:
  • Gene therapy (viral vectors, CRISPR, gene replacement, gene editing) > Search first: ClinicalTrials.gov, FDA gene therapy database, ASGCT resources
  • Cell therapy (stem cell transplant, CAR-T, cellular therapeutics) > Search first: ClinicalTrials.gov, FDA cell therapy database, FACT standards
  • RNA-based therapies (ASOs, siRNA, mRNA therapies) > Search first: ClinicalTrials.gov, FDA approvals, PubMed
  • Targeted therapies (treatments directed at specific molecular targets) > Search first: My Cancer Genome, OncoKB, ClinicalTrials.gov, FDA approvals
  • Immunotherapies (checkpoint inhibitors, monoclonal antibodies) > Search first: Cancer Immunotherapy Database, FDA approvals, ClinicalTrials.gov
  • Surgical and Interventional:
  • Surgical interventions (types of surgery, timing, outcomes) > Search first: CPT codes, surgical registries, clinical guidelines, PubMed
  • Supportive and Rehabilitative:
  • Supportive care (symptom management, pain control, nutrition) > Search first: Clinical guidelines, Cochrane Library, PubMed
  • Rehabilitation (physical therapy, occupational therapy, speech therapy) > Search first: Rehabilitation medicine databases, clinical guidelines, PubMed
  • Experimental:
  • Experimental treatments in clinical trials (with NCT identifiers if available) > Search first: ClinicalTrials.gov, EU Clinical Trials Register, WHO ICTRP
  • Treatment Outcomes:
  • Treatment response rates > Search first: Clinical trial databases, FDA reviews, systematic reviews, PubMed
  • Side effects and adverse events > Search first: FDA Adverse Event Reporting System (FAERS), MedWatch, PubMed
  • Treatment Strategy:
  • Treatment algorithms (clinical pathways, decision trees) > Search first: Clinical practice guidelines, NCCN Guidelines, UpToDate
  • Combination therapies > Search first: ClinicalTrials.gov, treatment guidelines, PubMed
  • Personalized medicine approaches (genotype-guided treatment) > Search first: My Cancer Genome, CIViC, PharmGKB, precision medicine databases

For each treatment, suggest MAXO (Medical Action Ontology) terms where applicable.

13. Prevention

  • Prevention Levels:
  • Primary prevention (preventing disease occurrence: vaccination, risk factor modification) > Search first: CDC, WHO, USPSTF recommendations, Cochrane Library
  • Secondary prevention (early detection and treatment: screening programs, early intervention) > Search first: USPSTF, CDC screening guidelines, WHO
  • Tertiary prevention (preventing complications in those with disease) > Search first: Clinical guidelines, disease management protocols, PubMed
  • Immunization: Vaccine strategies (if applicable)

    Search first: CDC vaccine schedules, WHO immunization, FDA vaccine database

  • Screening and Early Detection:
  • Screening programs (population-based: newborn screening, cancer screening) > Search first: CDC screening programs, USPSTF, cancer screening databases
  • Genetic screening (carrier screening, preimplantation genetic diagnosis, prenatal testing) > Search first: ACMG recommendations, ACOG guidelines, GTR
  • Risk stratification (identifying high-risk individuals for targeted prevention) > Search first: Risk prediction models, clinical calculators, PubMed
  • Behavioral Interventions: Lifestyle modifications to reduce risk

    Search first: CDC, WHO, behavioral intervention databases, Cochrane Library

  • Counseling: Genetic counseling (risk assessment, family planning guidance)

    Search first: NSGC resources, ACMG guidelines, GeneReviews

  • Public Health:
  • Public health interventions (sanitation, vector control, health education) > Search first: CDC, WHO, public health databases, PubMed
  • Environmental interventions (reducing environmental risk factors) > Search first: EPA databases, WHO environmental health, PubMed
  • Prophylaxis: Preventive medications or procedures

    Search first: Clinical guidelines, FDA approvals, PubMed

14. Other Species / Natural Disease

  • Taxonomy: Species affected (with NCBI Taxon identifiers)

    Search first: NCBI Taxonomy

  • Breed: Specific breeds affected (with VBO identifiers if applicable)

    Search first: VBO (Vertebrate Breed Ontology)

  • Gene: Orthologous genes in other species (with NCBI Gene IDs)

    Search first: NCBI Gene

  • Natural Disease:
  • Naturally occurring disease in other species (companion animals, wildlife) > Search first: OMIA (Online Mendelian Inheritance in Animals), VetCompass, PubMed
  • Veterinary relevance and importance in animal health > Search first: OMIA, veterinary databases, PubMed
  • Comparative Biology:
  • Comparative pathology (similarities and differences across species) > Search first: OMIA, comparative pathology databases, PubMed
  • Evolutionary conservation of disease mechanisms > Search first: HomoloGene, OrthoMCL, Alliance of Genome Resources
  • Transmission (if applicable):
  • Zoonotic potential > Search first: CDC zoonotic diseases, WHO zoonoses, GIDEON
  • Cross-species susceptibility > Search first: NCBI Taxonomy, veterinary databases, PubMed

15. Model Organisms

  • Model Types:
  • Model organism type (mammalian, invertebrate, cellular, in vitro) > Search first: Alliance of Genome Resources, model organism databases
  • Specific model systems (mouse, rat, zebrafish, Drosophila, C. elegans, yeast, cell lines, organoids, iPSCs) > Search first: MGI, RGD, ZFIN, FlyBase, WormBase, SGD, ATCC, Cellosaurus
  • Induced models (drug treatment, surgical intervention, environmental manipulation) > Search first: MGI, model organism databases, PubMed
  • Genetic Models:
  • Types available (knockout, knock-in, transgenic, conditional, humanized) > Search first: MGI, IMPC, KOMP, EuMMCR, IMSR
  • Model Characteristics:
  • Phenotype recapitulation (how well model reproduces human disease features) > Search first: Model organism databases, comparative studies, PubMed
  • Model limitations (aspects of human disease not captured) > Search first: Model organism databases, PubMed, review articles
  • Applications:
  • Research applications (what aspects of disease can be studied) > Search first: Model organism databases, PubMed
  • Resources:
  • Model databases > Search first: MGI, RGD, ZFIN, FlyBase, WormBase, IMSR, EMMA, MMRRC

Citation Requirements

  • Cite primary literature (PMID preferred) for all mechanistic and clinical claims
  • Prioritize recent reviews and landmark papers
  • Include direct quotes from abstracts where possible to support key statements
  • Distinguish evidence source types: human clinical, model organism, in vitro, computational

Output Format

Structure your response as a comprehensive narrative organized by the sections above. For each section, provide: - Factual content with specific details (numbers, percentages, gene names, variant nomenclature) - Ontology term suggestions (HPO, GO, CL, UBERON, CHEBI, MAXO, MONDO) where applicable - Evidence citations with PMIDs - Direct quotes from abstracts to support key claims - Clear indication when information is not available or not applicable for this disease

This report will be used to populate a disease knowledge base entry with: - Pathophysiology descriptions with causal chains - Gene/protein annotations (HGNC, GO terms) - Phenotype associations (HP terms) with frequencies - Cell type involvement (CL terms) - Anatomical locations (UBERON terms) - Chemical entities (CHEBI terms) - Treatment annotations (MAXO terms) - Evidence items with PMIDs and exact abstract quotes - Epidemiology, prognosis, diagnostic, and prevention information - Animal model descriptions with phenotype recapitulation details

Inherited Porphyria — Disease Characteristics Research Report (2023–2024 priority)

Target disease

Disease name (umbrella): Inherited porphyrias (group of Mendelian inborn errors of heme biosynthesis; includes acute hepatic and erythropoietic/cutaneous subtypes). (dickey2024updateonthe pages 1-3)

Note on scope: “Inherited porphyria” is not a single disease entity but a family of disorders caused by defects at different enzymatic steps in the heme biosynthetic pathway; therefore, the knowledge-base entry typically needs a parent concept (“porphyrias”) plus child subtype entities (e.g., AIP, VP, HCP, ADP, EPP, XLP, CEP). (dickey2024updateonthe pages 1-3, dickey2024updateonthe pages 3-5)

Key knowledge-base identifiers (requested): OMIM numbers for several subtypes are present in retrieved evidence (e.g., AIP OMIM #176000; EPP OMIM 177000; XLP OMIM 300752). However, MONDO / Orphanet / ICD-10 / ICD-11 / MeSH identifiers were not retrieved in the current evidence set and therefore cannot be cited here without additional retrieval. (belosevic2023firstreportof pages 1-2, annaelisabeth2023afamelanotideisassociated pages 2-3)

Information source type: The evidence used here is derived primarily from aggregated disease-level resources (recent authoritative reviews) plus human clinical trial/real-world cohort studies for modern therapies; there is also limited evidence from single-patient case/genetics reports (e.g., mosaic HMBS variant). (dickey2024updateonthe pages 1-3, sardh2024longtermfollowupof pages 7-10, kubisch2024germanrealworldexperience pages 1-2, belosevic2023firstreportof pages 1-2)

1. Disease information (overview, concepts, definitions)

Definition and classification (current understanding)

Porphyrias are “rare disorders caused by enzymatic defects in heme synthesis” and can be classified by primary site of intermediate accumulation (hepatic vs erythropoietic) and clinically as acute hepatic porphyrias (AHP) versus cutaneous porphyrias (including blistering vs nonblistering photosensitivity phenotypes). (dickey2024updateonthe pages 1-3)

Major inherited subtypes explicitly listed in 2024 review evidence: AIP, VP, HCP, ADP, EPP, XLP, PCT, CEP. (dickey2024updateonthe pages 1-3)

Visual summary: A heme-biosynthesis pathway diagram linking each enzymatic step to the corresponding porphyria subtype is available in the retrieved evidence. (dickey2024updateonthe media 522948f9)

Synonyms / alternative names

  • Acute hepatic porphyrias (AHP): includes AIP, VP, HCP, ADP. (dickey2024updateonthe pages 1-3)
  • Protoporphyrias: EPP and XLP. (madigan2023illuminatingdersimelagona pages 2-3, leaf2024afamelanotidefortreatment pages 1-2)

2. Etiology (causal factors, triggers, risk/protective factors, G×E)

Primary causal factors (genetic / mechanistic)

Inherited porphyrias arise from pathogenic variants affecting enzymes of the heme biosynthetic pathway; for AHP, “pathogenic variants in 1 of 4 enzymes of heme synthesis are necessary” with attacks requiring induction of hepatic ALAS1 (rate-limiting step in liver). (dickey2024givosiranatargeted pages 4-5)

AHP causal genes (2024 review): - AIP: HMBS (hydroxymethylbilane synthase) (dickey2024updateonthe pages 1-3) - VP: PPOX (protoporphyrinogen oxidase) (dickey2024updateonthe pages 1-3) - HCP: CPOX (coproporphyrinogen oxidase) (dickey2024updateonthe pages 1-3) - ADP: ALAD (aminolevulinate dehydratase) (dickey2024updateonthe pages 1-3)

Erythropoietic protoporphyria / X-linked protoporphyria: - EPP: FECH deficiency (ferrochelatase, final step) (madigan2023illuminatingdersimelagona pages 2-3) - XLP: ALAS2 gain-of-function (erythroid ALAS2) (madigan2023illuminatingdersimelagona pages 2-3)

Environmental/physiologic triggers (risk factors for attack expression)

Acute attacks in AHP relate to induction of hepatic ALAS1 and accumulation of neurotoxic precursors ALA and PBG, and are triggered by stressors including “stress, alcohol, smoking, medications, caloric restriction/fasting, acute illnesses, and the luteal menstrual phase.” (dickey2024updateonthe pages 3-5)

A case-based genetics report similarly lists triggers including “drugs metabolised via the cytochrome P450 pathway, exogenous and endogenous hormones, stress, and reduced carbohydrate intake.” (belosevic2023firstreportof pages 1-2)

Genetic modifiers / penetrance modifiers (recent developments)

AIP is widely recognized as autosomal dominant with low penetrance and high heterogeneity. (lei2024acuteintermittentporphyria pages 1-2)

Recent (2023–2024) evidence supports multiple modifier axes: - Mitochondrial biogenesis / mtDNA copy number: A 2023 human study measured mtDNA copy number in blood (34 AIP vs 37 controls) and reported all AIP patients had low mitochondrial count; “mtDNA copy number per cell and mitochondrial biogenesis seem to play a role in either inhibiting or promoting disease expression,” and are proposed as biomarkers. (pierro2023mitochondrialdnacopy pages 1-2) - Oligogenic/modifier genes: A 2024 review highlights candidate modifier loci including CYP2D6 (some alleles potentially protective via reduced sensitivity to porphyrogenic metabolites), PEPT2 variants linked to differences in renal failure severity/neurotoxicity via altered ALA handling, and other genes (AGRN, DOK7, SCN4A, PPARA). (lei2024acuteintermittentporphyria pages 2-3, lei2024acuteintermittentporphyria pages 4-5) - Somatic mosaicism: 2023 report describes a de novo low-frequency mosaic HMBS pathogenic variant (c.77G>A p.Arg26His at ~22% allele fraction) causing AIP, detectable only via long-read sequencing when routine testing was negative. (belosevic2023firstreportof pages 1-2)

Protective factors

Protective genetic variants are not established in the retrieved clinical evidence set, but the modifier-gene literature suggests some alleles may reduce sensitivity to porphyrogenic metabolites (e.g., selected CYP2D6 alleles) and thereby lower risk of symptomatic expression. (lei2024acuteintermittentporphyria pages 2-3)

3. Phenotypes (clinical manifestations, onset, frequency, QoL)

Acute hepatic porphyrias (AHP; especially AIP)

Core clinical phenotype: acute neurovisceral attacks (often abdominal pain with nausea/vomiting) with neurologic/autonomic features; diagnostic delay is common. (dickey2024updateonthe pages 3-5)

Attack-associated biochemical phenotype: elevated urinary ALA and PBG during symptomatic episodes. (dickey2024updateonthe pages 3-5, belosevic2023firstreportof pages 1-2)

Onset/temporal pattern: attacks typically after puberty and are episodic, precipitated by triggers. (belosevic2023firstreportof pages 1-2)

Long-term complications (AHP/AIP): chronic pain, neuropathy, liver and kidney disease; one 2024 review notes chronic kidney disease occurs in “about 60% of symptomatic AIP.” (dickey2024updateonthe pages 5-6)

Suggested HPO terms (non-exhaustive; based on symptoms explicitly mentioned in retrieved evidence): - Abdominal pain (HP:0002027) (dickey2024updateonthe pages 5-6) - Nausea (HP:0002018) (dickey2024updateonthe pages 5-6) - Vomiting (HP:0002013) (dickey2024updateonthe pages 3-5) - Peripheral neuropathy (HP:0009830) (dickey2024updateonthe pages 5-6) - Autonomic dysfunction (HP:0002459) (dickey2024updateonthe pages 5-6) - Hyponatremia (HP:0002902) (belosevic2023firstreportof pages 1-2) - Psychiatric symptoms (HP:0000708) (belosevic2023firstreportof pages 1-2)

Protoporphyrias (EPP/XLP)

Core phenotype: severe cutaneous phototoxicity; EPP described as “painful phototoxic burn injuries after short exposure times to visible light.” (barmanaksozen2023qualityadjustedlifeyears pages 1-2)

QoL impact: large, measurable QoL improvements are seen with afamelanotide therapy in real-world cohorts (see Treatment). (leaf2024afamelanotidefortreatment pages 2-5)

Suggested HPO terms: - Photosensitivity (HP:0000992) - Cutaneous pain (HP:0000989) - Erythromelalgia-like pain after sun exposure (phenotypic description; closest HPO often Photosensitivity + Pain)

Congenital erythropoietic porphyria (CEP)

Clinical features noted include fluorescent erythrodontia, red fluorescent urine, corneal ulcers, thrombocytopenia, and transfusion-dependent anemia; severity ranges from hydrops fetalis to adult-onset mild photosensitivity. (dickey2024updateonthe pages 10-11)

Suggested HPO terms: - Hemolytic anemia / anemia (HP:0001903) - Thrombocytopenia (HP:0001873) - Photosensitivity (HP:0000992) - Corneal ulceration (HP:0000481)

4. Genetic / molecular information

Causal genes and inheritance patterns (from retrieved evidence)

See table artifact below and the pathway figure. Acute hepatic porphyrias include AD low-penetrance diseases (AIP/VP/HCP) and ultrarare recessive ADP. (dickey2024updateonthe pages 1-3, dickey2024updateonthe pages 3-5)

AIP genetics details: AIP is caused by HMBS pathogenic variants (many reported) with very low population penetrance (~1% of heterozygotes symptomatic reported in the mtDNA-copy-number paper’s background). (pierro2023mitochondrialdnacopy pages 1-2)

Variant-type examples and diagnostic-edge cases (2023–2024): - Somatic mosaic HMBS variant c.77G>A p.(Arg26His) at ~22% allele fraction, requiring long-read sequencing to detect. (belosevic2023firstreportof pages 1-2)

Modifier genes (selected)

Proposed modifiers include CYP2D6 alleles and PEPT2 variants, with potential effects on xenobiotic metabolism and ALA handling, respectively. (lei2024acuteintermittentporphyria pages 2-3, lei2024acuteintermittentporphyria pages 4-5)

Epigenetic / chromosomal abnormality evidence

Not identified in retrieved sources.

5. Environmental information

Key non-genetic contributors (attack precipitants): fasting/caloric restriction, alcohol, smoking, acute illness, medications (porphyrinogenic/CYP450-related), and hormonal cycling (luteal phase/progesterone effects). (dickey2024updateonthe pages 3-5, belosevic2023firstreportof pages 1-2)

6. Mechanism / pathophysiology

Core biochemical mechanism (causal chain)

Upstream trigger: induction of hepatic ALAS1 (rate-limiting heme synthesis enzyme in liver) by physiologic/environmental stimuli. (dickey2024updateonthe pages 3-5, dickey2024givosiranatargeted pages 4-5)

Primary defect: inherited partial deficiency in a downstream heme biosynthesis enzyme (e.g., HMBS in AIP). (dickey2024updateonthe pages 1-3)

Downstream accumulation: increased intermediates including ALA and PBG (especially in AHP), with ALA “particularly toxic” and implicated as neurotoxic. (dickey2024updateonthe pages 3-5, kubisch2024germanrealworldexperience pages 1-2)

Clinical manifestations: neurovisceral attacks with pain, autonomic and neurologic complications, and chronic organ sequelae (kidney/liver). (dickey2024updateonthe pages 5-6, dickey2024updateonthe pages 3-5)

Photosensitivity mechanism in protoporphyrias (high level)

In EPP/XLP, excess protoporphyrin IX accumulates, driving painful photosensitivity and, in a minority, hepatobiliary complications due to elimination of excess PPIX. (annaelisabeth2023afamelanotideisassociated pages 2-3)

Ontology suggestions

GO biological process (examples): - heme biosynthetic process (GO:0006783) - porphyrin-containing compound metabolic process (GO:0006778)

Cell Ontology (examples): - hepatocyte (CL:0000182) for hepatic ALAS1-driven AHP mechanisms - erythroblast / erythroid progenitor (e.g., erythroblast CL:0000765) for ALAS2/FECH context in protoporphyrias

UBERON (examples): - liver (UBERON:0002107) - skin of body (UBERON:0002097)

CHEBI (examples): - δ-aminolevulinic acid (CHEBI:13772) - porphobilinogen (CHEBI:15508) - protoporphyrin IX (CHEBI:15439)

(These ontology IDs are standard terms; specific mapping was not provided in the retrieved papers.)

7. Anatomical structures affected

Primary organs (by subtype grouping): - Acute hepatic porphyrias: liver as the key metabolic source of precursor overproduction; secondary complications include kidney disease and neurologic system involvement. (dickey2024updateonthe pages 3-5, dickey2024updateonthe pages 5-6) - Protoporphyrias (EPP/XLP): skin (phototoxicity) and liver (subset with cholestatic damage/liver failure). (barmanaksozen2023qualityadjustedlifeyears pages 1-2, annaelisabeth2023afamelanotideisassociated pages 1-2)

8. Temporal development

AHP (AIP): episodic acute attacks precipitated by triggers; low penetrance means many carriers remain asymptomatic. (dickey2024updateonthe pages 3-5, lei2024acuteintermittentporphyria pages 1-2)

Protoporphyrias: chronic photosensitivity with acute painful reactions after short visible light exposure. (barmanaksozen2023qualityadjustedlifeyears pages 1-2)

9. Inheritance and population

Epidemiology (selected quantitative estimates from retrieved evidence)

  • AIP prevalence: ~0.5–2 per 100,000 clinically (review) (dickey2024updateonthe pages 3-5)
  • Carrier frequency of HMBS pathogenic variants: ~1:1,700 reported in genetic datasets, implying overall penetrance <1% in the general population, but higher (10–20%) among relatives of symptomatic patients. (dickey2024updateonthe pages 3-5)

  • AIP population prevalence estimate (another 2024 review): 5–10 cases per 100,000; acute attacks in <1% of at-risk individuals. (lei2024acuteintermittentporphyria pages 1-2)

  • EPP prevalence: ~1:100,000 (reported in 2023 QoL feasibility study and 2023 liver-protection study). (barmanaksozen2023qualityadjustedlifeyears pages 1-2, annaelisabeth2023afamelanotideisassociated pages 1-2)

Penetrance/expressivity

  • AIP penetrance heterogeneity: genotype-dependent penetrance described, with population penetrance ~0.5–1% vs family penetrance higher; null HMBS alleles associated with higher penetrance/severity than missense alleles. (lei2024acuteintermittentporphyria pages 3-4, lei2024acuteintermittentporphyria pages 2-3)

10. Diagnostics

Biochemical testing (first-line in symptomatic patients)

A 2024 review emphasizes that spot urine ALA and PBG normalized to creatinine are key for diagnosing acute attacks; urine porphyrins alone are nonspecific; stool and plasma porphyrins help with VP/HCP and cutaneous presentations. Testing should be obtained during attacks because PBG can normalize between episodes. (dickey2024updateonthe pages 3-5)

A recent diagnostic-recommendations review (2025) reinforces that clinical features alone are insufficient, and diagnosis in symptomatic patients requires biochemical demonstration of characteristic heme precursor/porphyrin patterns; it warns that genomic sequencing should not be used as initial screening without biochemical evidence in symptomatic patients. (aarsand2025practicalrecommendationsfor pages 1-2)

Genetic testing

Genetic testing is recommended to confirm subtype and test at-risk relatives; enzyme assays may have overlapping ranges and limited usefulness. (dickey2024updateonthe pages 5-6, dickey2024updateonthe pages 3-5)

Advanced sequencing in edge cases: somatic mosaicism can evade Sanger sequencing; long-read sequencing can detect low-level mosaic HMBS variants. (belosevic2023firstreportof pages 1-2)

Protoporphyria diagnostics

EPP/XLP diagnosis begins with total erythrocyte protoporphyrin; metal-free fraction is typically >90% in EPP and 50–85% in XLP; plasma alone is not recommended; plasma fluorescence emission peak at 634 nm supports EPP/XLP. (madigan2023illuminatingdersimelagona pages 2-3)

11. Outcome / prognosis

AHP/AIP chronic morbidity: chronic kidney disease is reported in “about 60% of symptomatic AIP” in a 2024 review, consistent with significant long-term morbidity burden. (dickey2024updateonthe pages 5-6)

EPP liver outcomes: ~20% of EPP patients have disturbed liver function and ~4% progress to terminal liver failure from hepatobiliary elimination of excess PPIX. (annaelisabeth2023afamelanotideisassociated pages 1-2)

(Quantitative survival curves and mortality rates were not present in the retrieved evidence set.)

12. Treatment (current practice, recent developments 2023–2024, real-world implementation)

Acute hepatic porphyrias / AIP

Trigger avoidance: avoidance of unsafe medications, fasting, alcohol, tobacco is emphasized as foundational management. (dickey2024updateonthe pages 5-6)

Acute attacks: intravenous hemin (example dosing given in review: 3–4 mg/kg daily for 4 days) plus supportive care (analgesia, antiemetics, electrolyte monitoring). (dickey2024updateonthe pages 5-6)

RNAi disease-modifying therapy — givosiran (ALAS1-targeting): - Mechanism: inhibits hepatic ALAS1 to reduce ALA/PBG accumulation. (dickey2024givosiranatargeted pages 4-5) - Phase 1/2 open-label extension (48 months; Orphanet J Rare Dis; Oct 2024; URL https://doi.org/10.1186/s13023-024-03284-w): annualized attack rates and hemin use reduced by 97% and 96%; median urinary ALA −95% and PBG −98% at month 48; QoL improved (EQ-VAS +15.8 points; EQ-5D-5L +0.04). (sardh2024longtermfollowupof pages 7-10, sardh2024longtermfollowupof pages 10-12, sardh2024longtermfollowupof pages 1-2) - Real-world cohort (Germany; J Clin Med; Nov 2024; URL https://doi.org/10.3390/jcm13226779): historical AAR 2.9 reduced to 0.45 on givosiran (p<0.01); 75% symptom improvement; biochemical response with ALA <2×ULN in all and PBG <2×ULN in 60% at 6 months. (kubisch2024germanrealworldexperience pages 1-2) - Safety signals summarized in 2024 hematology review (URL https://doi.org/10.1182/hematology.2024000663): injection-site reactions and nausea; ALT >3×ULN in 15% vs 2% placebo; abnormal renal function ~15% vs 7% placebo; elevated homocysteine 16% in trial summary. (dickey2024givosiranatargeted pages 4-5) - Additional real-world safety observations (Germany): fatigue leading to discontinuation in some; decreased renal function 30.7%, hepatic enzyme elevations, and homocysteinemia observed in all patients in that cohort excerpt. (kubisch2024germanrealworldexperience pages 12-14)

MAXO suggestions (examples): - Intravenous hemin therapy (MAXO: medical intervention concept; specific ID not retrieved) - RNA interference therapy (givosiran) (MAXO concept; ID not retrieved)

Protoporphyrias (EPP/XLP)

Afamelanotide (α-MSH analogue; implant): - US cohort (Life; May 2024; URL https://doi.org/10.3390/life14060689): median time to phototoxic symptom onset improved from 12.5 min to 120 min (p<0.0001) in those receiving ≥2 implants; disease-specific QoL (EPP-QoL) improved from 27.8 to 75 (p=0.00067); no improvement in liver biochemistries in that cohort despite clinical benefit. (leaf2024afamelanotidefortreatment pages 2-5) - QoL feasibility (IJERPH; Mar 2023; URL https://doi.org/10.3390/ijerph20075296): reports EPP prevalence ~1:100,000 and that EQ-5D under long-term afamelanotide was “comparable to the age-matched population norm.” (barmanaksozen2023qualityadjustedlifeyears pages 1-2) - Liver-protection observational evidence (Life; Apr 2023; URL https://doi.org/10.3390/life13041066): dose-dependent associations between more frequent dosing (more implants in prior 365 days) and lower ALAT and bilirubin; supports potential hepatoprotective effect signals in EPP. (annaelisabeth2023afamelanotideisassociated pages 1-2)

Emerging therapy — dersimelagon (oral MC1R agonist): a 2023 review summarizes phase 2 evidence of clinically meaningful and statistically significant benefit with acceptable safety/efficacy profile for EPP/XLP. (madigan2023illuminatingdersimelagona pages 2-3)

MAXO suggestions (examples): - Subcutaneous drug implantation (afamelanotide implant) (MAXO concept; ID not retrieved) - Photoprotection / sunlight avoidance (MAXO concept; ID not retrieved)

CEP

Bone marrow transplantation is described as curative in transfusion-dependent or disfiguring disease. (dickey2024updateonthe pages 10-11)

13. Prevention

Primary prevention (genetic risk cannot be prevented, but attacks can be prevented): avoidance of known triggers (unsafe medications, fasting/caloric restriction, alcohol/tobacco; management of hormonal triggers). (dickey2024updateonthe pages 5-6, dickey2024updateonthe pages 3-5)

Secondary prevention: family screening with genetic testing for at-risk relatives after biochemical/genetic confirmation in index case. (dickey2024updateonthe pages 5-6, dickey2024updateonthe pages 3-5)

Tertiary prevention: long-term suppression of attacks (e.g., givosiran in appropriate patients) and monitoring/management of renal/hepatic complications. (dickey2024givosiranatargeted pages 4-5, kubisch2024germanrealworldexperience pages 12-14)

14. Other species / natural disease

Not identified in the retrieved evidence set.

15. Model organisms

Not identified in the retrieved evidence set.

High-value recent resources used (with publication dates and URLs)

  • Dickey AK, Leaf RK, Balwani M. Update on the porphyrias. Annual Review of Medicine (Jan 2024). https://doi.org/10.1146/annurev-med-042921-123602 (dickey2024updateonthe pages 1-3, dickey2024updateonthe pages 3-5)
  • Sardh E, et al. Long-term follow-up of givosiran… 48-month OLE. Orphanet Journal of Rare Diseases (Oct 2024). https://doi.org/10.1186/s13023-024-03284-w (sardh2024longtermfollowupof pages 7-10)
  • Kubisch I, et al. German real-world experience… givosiran. Journal of Clinical Medicine (Nov 2024). https://doi.org/10.3390/jcm13226779 (kubisch2024germanrealworldexperience pages 1-2)
  • Leaf RK, et al. Afamelanotide… US cohort. Life (May 2024). https://doi.org/10.3390/life14060689 (leaf2024afamelanotidefortreatment pages 2-5)
  • Lei JJ, et al. AIP low penetrance/high heterogeneity (modifier genes). Frontiers in Genetics (Aug 2024). https://doi.org/10.3389/fgene.2024.1374965 (lei2024acuteintermittentporphyria pages 1-2)
  • Di Pierro E, et al. mtDNA copy number drives penetrance. Life (Sep 2023). https://doi.org/10.3390/life13091923 (pierro2023mitochondrialdnacopy pages 1-2)

Summary table of major inherited subtypes

Clinical category Subtype Causal gene and enzyme/step Inheritance Key diagnostic biochemical markers Current disease-modifying therapies highlighted in 2023–2024 evidence
Acute hepatic AIP HMBS; hydroxymethylbilane synthase, 3rd enzyme of heme biosynthesis AD, low penetrance Spot urine ALA and PBG normalized to creatinine; elevated urinary ALA/PBG during attacks; urine porphyrins alone nonspecific Acute treatment with IV hemin and glucose/carbohydrate support; prevention with givosiran for AHP/AIP; trigger avoidance (dickey2024updateonthe pages 1-3, dickey2024updateonthe pages 3-5, dickey2024givosiranatargeted pages 4-5, sardh2024longtermfollowupof pages 7-10)
Acute hepatic VP PPOX; protoporphyrinogen oxidase AD, low penetrance Urine ALA/PBG in attacks; stool and plasma porphyrins aid diagnosis; can have cutaneous photosensitivity Hemin/glucose for acute attacks in AHP framework; givosiran approved for AHP; subtype-specific quantitative VP treatment data not in retrieved evidence (dickey2024updateonthe pages 1-3, dickey2024updateonthe pages 3-5, dickey2024updateonthe pages 5-6)
Acute hepatic HCP CPOX; coproporphyrinogen oxidase AD, low penetrance Urine ALA/PBG in attacks; stool and plasma porphyrins aid diagnosis; may show cutaneous photosensitivity Hemin/glucose for acute attacks in AHP framework; givosiran approved for AHP; subtype-specific HCP outcome data not in retrieved evidence (dickey2024updateonthe pages 1-3, dickey2024updateonthe pages 3-5, dickey2024updateonthe pages 5-6)
Acute hepatic ADP ALAD; aminolevulinate dehydratase AR (ultrarare) Urine ALA/PBG mentioned within AHP diagnostic framework; subtype-specific marker pattern not in retrieved evidence Not in retrieved evidence beyond general AHP management context (dickey2024updateonthe pages 1-3, dickey2024updateonthe pages 3-5)
Cutaneous / erythropoietic EPP FECH; ferrochelatase, final enzyme in heme biosynthesis AR Total erythrocyte protoporphyrin elevated; metal-free erythrocyte protoporphyrin >90% typical; plasma may be normal or increased; plasma fluorescence peak at 634 nm supports diagnosis Afamelanotide approved; large QoL/light-tolerance benefit in 2024 US cohort; dersimelagon emerging oral therapy; liver transplant discussed for severe liver failure risk in background evidence (madigan2023illuminatingdersimelagona pages 2-3, leaf2024afamelanotidefortreatment pages 2-5, leaf2024afamelanotidefortreatment pages 1-2, barmanaksozen2023qualityadjustedlifeyears pages 1-2, annaelisabeth2023afamelanotideisassociated pages 1-2)
Cutaneous / erythropoietic XLP ALAS2 gain-of-function; erythroid-specific first/rate-controlling step X-linked Total erythrocyte protoporphyrin elevated; metal-free fraction 50–85% typical; plasma fluorescence peak at 634 nm supports diagnosis Afamelanotide used for protoporphyrias in 2024 cohort (1 XLP patient included); dersimelagon emerging for EPP/XLP (madigan2023illuminatingdersimelagona pages 2-3, leaf2024afamelanotidefortreatment pages 2-5, leaf2024afamelanotidefortreatment pages 1-2)
Cutaneous / erythropoietic CEP UROS; uroporphyrinogen III synthase Not in retrieved evidence Not in retrieved evidence for specific biochemical markers in gathered excerpts Supportive photoprotection; bone marrow transplantation described as curative for transfusion-dependent or disfiguring disease; phlebotomy in selected non-anemic patients; ciclopirox trial planned (dickey2024updateonthe pages 10-11)

Table: This table summarizes the major inherited porphyria subtypes discussed in the gathered evidence, linking each disorder to its causal gene, inheritance, key biochemical diagnostic markers, and therapies emphasized in 2023–2024 sources. It is useful as a quick disease-knowledge-base scaffold across acute hepatic and erythropoietic/cutaneous porphyrias.

Notes on evidence gaps vs requested template fields

1) Ontology/registry identifiers (MONDO, Orphanet, ICD-10/ICD-11, MeSH) were not retrievable from the current evidence set; the report therefore limits itself to OMIM identifiers that were explicitly present in the retrieved texts. (belosevic2023firstreportof pages 1-2, annaelisabeth2023afamelanotideisassociated pages 2-3) 2) Animal models, model organism databases, and cross-species natural disease were not identified in the retrieved evidence set. 3) Where HPO/GO/CL/UBERON/CHEBI/MAXO terms are suggested, they are standard ontology terms; the retrieved evidence did not provide ontology IDs directly.

Figure

A pathway figure showing heme biosynthesis steps, subcellular localization (mitochondrial vs cytosolic), and porphyria subtype mapping is available from the 2024 Annual Review of Medicine article. (dickey2024updateonthe media 522948f9)

References

  1. (dickey2024updateonthe pages 1-3): Amy K. Dickey, Rebecca Karp Leaf, and Manisha Balwani. Update on the porphyrias. Annual Review of Medicine, 75:321-335, Jan 2024. URL: https://doi.org/10.1146/annurev-med-042921-123602, doi:10.1146/annurev-med-042921-123602. This article has 47 citations and is from a domain leading peer-reviewed journal.

  2. (dickey2024updateonthe pages 3-5): Amy K. Dickey, Rebecca Karp Leaf, and Manisha Balwani. Update on the porphyrias. Annual Review of Medicine, 75:321-335, Jan 2024. URL: https://doi.org/10.1146/annurev-med-042921-123602, doi:10.1146/annurev-med-042921-123602. This article has 47 citations and is from a domain leading peer-reviewed journal.

  3. (belosevic2023firstreportof pages 1-2): Adrian Belosevic, Anna-Elisabeth Minder, Morgan Gueuning, Franziska van Breemen, Gian Andri Thun, Maja P. Mattle-Greminger, Stefan Meyer, Alessandra Baumer, Elisabeth I. Minder, Xiaoye Schneider-Yin, and Jasmin Barman-Aksözen. First report of a low-frequency mosaic mutation in the hydroxymethylbilane synthase gene causing acute intermittent porphyria. Life, 13:1889, Sep 2023. URL: https://doi.org/10.3390/life13091889, doi:10.3390/life13091889. This article has 1 citations.

  4. (annaelisabeth2023afamelanotideisassociated pages 2-3): Anna-Elisabeth Minder, Xiaoye Schneider-Yin, Henryk Zulewski, Christoph E. Minder, and Elisabeth I. Minder. Afamelanotide is associated with dose-dependent protective effect from liver damage related to erythropoietic protoporphyria. Life, Apr 2023. URL: https://doi.org/10.3390/life13041066, doi:10.3390/life13041066. This article has 8 citations.

  5. (sardh2024longtermfollowupof pages 7-10): Eliane Sardh, Manisha Balwani, David C. Rees, Karl E. Anderson, Gang Jia, Marianne T. Sweetser, and Bruce Wang. Long-term follow-up of givosiran treatment in patients with acute intermittent porphyria from a phase 1/2, 48-month open-label extension study. Orphanet Journal of Rare Diseases, Oct 2024. URL: https://doi.org/10.1186/s13023-024-03284-w, doi:10.1186/s13023-024-03284-w. This article has 11 citations and is from a peer-reviewed journal.

  6. (kubisch2024germanrealworldexperience pages 1-2): Ilja Kubisch, Nils Wohmann, Thaddäus Till Wissniowski, Thomas Stauch, Lucienne Oettel, Eva Diehl-Wiesenecker, Rajan Somasundaram, and Ulrich Stölzel. German real-world experience of patients with diverse features of acute intermittent porphyria treated with givosiran. Journal of Clinical Medicine, 13:6779, Nov 2024. URL: https://doi.org/10.3390/jcm13226779, doi:10.3390/jcm13226779. This article has 9 citations.

  7. (dickey2024updateonthe media 522948f9): Amy K. Dickey, Rebecca Karp Leaf, and Manisha Balwani. Update on the porphyrias. Annual Review of Medicine, 75:321-335, Jan 2024. URL: https://doi.org/10.1146/annurev-med-042921-123602, doi:10.1146/annurev-med-042921-123602. This article has 47 citations and is from a domain leading peer-reviewed journal.

  8. (madigan2023illuminatingdersimelagona pages 2-3): Katelyn E. Madigan, Sean R. Rudnick, Matthew A. Agnew, Numra Urooj, and Herbert L. Bonkovsky. Illuminating dersimelagon: a novel agent in the treatment of erythropoietic protoporphyria and x-linked protoporphyria. Pharmaceuticals, 17:31, Dec 2023. URL: https://doi.org/10.3390/ph17010031, doi:10.3390/ph17010031. This article has 7 citations.

  9. (leaf2024afamelanotidefortreatment pages 1-2): Rebecca K. Leaf, Hetanshi Naik, Paul Y. Jiang, Sarina B. Elmariah, Pamela Hodges, Jennifer Mead, John Trinidad, Behnam Saberi, Benny Tran, Sarah Valiante, Francesca Mernick, David E. Leaf, Karl E. Anderson, and Amy K. Dickey. Afamelanotide for treatment of the protoporphyrias: impact on quality of life and laboratory parameters in a us cohort. Life, 14:689, May 2024. URL: https://doi.org/10.3390/life14060689, doi:10.3390/life14060689. This article has 8 citations.

  10. (dickey2024givosiranatargeted pages 4-5): Amy K. Dickey and Rebecca K. Leaf. Givosiran: a targeted treatment for acute intermittent porphyria. Hematology, 2024:426-433, Dec 2024. URL: https://doi.org/10.1182/hematology.2024000663, doi:10.1182/hematology.2024000663. This article has 12 citations and is from a peer-reviewed journal.

  11. (lei2024acuteintermittentporphyria pages 1-2): Jia-Jia Lei, Shuang Li, Bai-Xue Dong, Jing Yang, and Yi Ren. Acute intermittent porphyria: a disease with low penetrance and high heterogeneity. Frontiers in Genetics, Aug 2024. URL: https://doi.org/10.3389/fgene.2024.1374965, doi:10.3389/fgene.2024.1374965. This article has 8 citations and is from a peer-reviewed journal.

  12. (pierro2023mitochondrialdnacopy pages 1-2): Elena Di Pierro, Miriana Perrone, Milena Franco, Francesca Granata, Lorena Duca, Debora Lattuada, Giacomo De Luca, and Giovanna Graziadei. Mitochondrial dna copy number drives the penetrance of acute intermittent porphyria. Life, 13:1923, Sep 2023. URL: https://doi.org/10.3390/life13091923, doi:10.3390/life13091923. This article has 6 citations.

  13. (lei2024acuteintermittentporphyria pages 2-3): Jia-Jia Lei, Shuang Li, Bai-Xue Dong, Jing Yang, and Yi Ren. Acute intermittent porphyria: a disease with low penetrance and high heterogeneity. Frontiers in Genetics, Aug 2024. URL: https://doi.org/10.3389/fgene.2024.1374965, doi:10.3389/fgene.2024.1374965. This article has 8 citations and is from a peer-reviewed journal.

  14. (lei2024acuteintermittentporphyria pages 4-5): Jia-Jia Lei, Shuang Li, Bai-Xue Dong, Jing Yang, and Yi Ren. Acute intermittent porphyria: a disease with low penetrance and high heterogeneity. Frontiers in Genetics, Aug 2024. URL: https://doi.org/10.3389/fgene.2024.1374965, doi:10.3389/fgene.2024.1374965. This article has 8 citations and is from a peer-reviewed journal.

  15. (dickey2024updateonthe pages 5-6): Amy K. Dickey, Rebecca Karp Leaf, and Manisha Balwani. Update on the porphyrias. Annual Review of Medicine, 75:321-335, Jan 2024. URL: https://doi.org/10.1146/annurev-med-042921-123602, doi:10.1146/annurev-med-042921-123602. This article has 47 citations and is from a domain leading peer-reviewed journal.

  16. (barmanaksozen2023qualityadjustedlifeyears pages 1-2): Jasmin Barman-Aksözen, Anna-Elisabeth Minder, Francesca Granata, Mårten Pettersson, Cornelia Dechant, Mehmet Hakan Aksözen, and Rocco Falchetto. Quality-adjusted life years in erythropoietic protoporphyria and other rare diseases: a patient-initiated eq-5d feasibility study. International Journal of Environmental Research and Public Health, 20:5296, Mar 2023. URL: https://doi.org/10.3390/ijerph20075296, doi:10.3390/ijerph20075296. This article has 8 citations.

  17. (leaf2024afamelanotidefortreatment pages 2-5): Rebecca K. Leaf, Hetanshi Naik, Paul Y. Jiang, Sarina B. Elmariah, Pamela Hodges, Jennifer Mead, John Trinidad, Behnam Saberi, Benny Tran, Sarah Valiante, Francesca Mernick, David E. Leaf, Karl E. Anderson, and Amy K. Dickey. Afamelanotide for treatment of the protoporphyrias: impact on quality of life and laboratory parameters in a us cohort. Life, 14:689, May 2024. URL: https://doi.org/10.3390/life14060689, doi:10.3390/life14060689. This article has 8 citations.

  18. (dickey2024updateonthe pages 10-11): Amy K. Dickey, Rebecca Karp Leaf, and Manisha Balwani. Update on the porphyrias. Annual Review of Medicine, 75:321-335, Jan 2024. URL: https://doi.org/10.1146/annurev-med-042921-123602, doi:10.1146/annurev-med-042921-123602. This article has 47 citations and is from a domain leading peer-reviewed journal.

  19. (annaelisabeth2023afamelanotideisassociated pages 1-2): Anna-Elisabeth Minder, Xiaoye Schneider-Yin, Henryk Zulewski, Christoph E. Minder, and Elisabeth I. Minder. Afamelanotide is associated with dose-dependent protective effect from liver damage related to erythropoietic protoporphyria. Life, Apr 2023. URL: https://doi.org/10.3390/life13041066, doi:10.3390/life13041066. This article has 8 citations.

  20. (lei2024acuteintermittentporphyria pages 3-4): Jia-Jia Lei, Shuang Li, Bai-Xue Dong, Jing Yang, and Yi Ren. Acute intermittent porphyria: a disease with low penetrance and high heterogeneity. Frontiers in Genetics, Aug 2024. URL: https://doi.org/10.3389/fgene.2024.1374965, doi:10.3389/fgene.2024.1374965. This article has 8 citations and is from a peer-reviewed journal.

  21. (aarsand2025practicalrecommendationsfor pages 1-2): Aasne K. Aarsand, Jordi To‐Figueras, Sharon Whatley, Sverre Sandberg, and Caroline Schmitt. Practical recommendations for biochemical and genetic diagnosis of the porphyrias. Liver International, Jun 2025. URL: https://doi.org/10.1111/liv.16012, doi:10.1111/liv.16012. This article has 20 citations and is from a peer-reviewed journal.

  22. (sardh2024longtermfollowupof pages 10-12): Eliane Sardh, Manisha Balwani, David C. Rees, Karl E. Anderson, Gang Jia, Marianne T. Sweetser, and Bruce Wang. Long-term follow-up of givosiran treatment in patients with acute intermittent porphyria from a phase 1/2, 48-month open-label extension study. Orphanet Journal of Rare Diseases, Oct 2024. URL: https://doi.org/10.1186/s13023-024-03284-w, doi:10.1186/s13023-024-03284-w. This article has 11 citations and is from a peer-reviewed journal.

  23. (sardh2024longtermfollowupof pages 1-2): Eliane Sardh, Manisha Balwani, David C. Rees, Karl E. Anderson, Gang Jia, Marianne T. Sweetser, and Bruce Wang. Long-term follow-up of givosiran treatment in patients with acute intermittent porphyria from a phase 1/2, 48-month open-label extension study. Orphanet Journal of Rare Diseases, Oct 2024. URL: https://doi.org/10.1186/s13023-024-03284-w, doi:10.1186/s13023-024-03284-w. This article has 11 citations and is from a peer-reviewed journal.

  24. (kubisch2024germanrealworldexperience pages 12-14): Ilja Kubisch, Nils Wohmann, Thaddäus Till Wissniowski, Thomas Stauch, Lucienne Oettel, Eva Diehl-Wiesenecker, Rajan Somasundaram, and Ulrich Stölzel. German real-world experience of patients with diverse features of acute intermittent porphyria treated with givosiran. Journal of Clinical Medicine, 13:6779, Nov 2024. URL: https://doi.org/10.3390/jcm13226779, doi:10.3390/jcm13226779. This article has 9 citations.