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1
Inheritance
5
Pathophys.
11
Phenotypes
22
Pathograph
1
Genes
4
Treatments
3
Differentials
1
Trials
13
References
1
Deep Research
👪

Inheritance

1
Autosomal recessive HP:0000007
ALAD porphyria is an autosomal recessive disorder usually caused by biallelic ALAD variants that leave very low residual enzyme activity.
Autosomal recessive inheritance
Show evidence (2 references)
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 ADP clinical update directly states autosomal recessive inheritance.
ORPHA:100924 SUPPORT Other
"Autosomal recessive"
Orphanet records autosomal recessive inheritance.

Pathophysiology

5
ALAD conformational and biallelic variant defects
Pathogenic ALAD variants can impair porphobilinogen synthase by destabilizing the active octameric enzyme, shifting the morpheein equilibrium toward low-activity hexamers, or producing unstable or low-activity mutant proteins. The result is profound residual ALAD activity loss in affected patients.
ALAD link
porphobilinogen synthase activity link ↓ DECREASED
Show evidence (3 references)
PMID:17236137 SUPPORT In Vitro
"Thus, all porphyria-associated human PBGS variants are found to shift the morpheein equilibrium for PBGS toward the less active hexamer. "
Biochemical expression work supports a conformational mechanism for multiple ALAD variants.
PMID:16343966 SUPPORT In Vitro
"These results suggest that the combination of the two aberrant ALADs with little enzyme activity accounts for the markedly decreased ALAD activity observed in the proband. "
In vitro expression of patient ALAD variants supports markedly reduced enzyme activity.
PMID:10706561 SUPPORT Human Clinical
"These data thus demonstrate that the proband was associated with 2 novel molecular defects of the ALAD gene, 1 in each allele, and account for the extremely low ALAD activity in his erythrocytes ( approximately 1% of normal). "
A second patient study supports biallelic ALAD defects with near-absent erythrocyte activity.
ALAD block in heme biosynthesis
ALAD, also known as porphobilinogen synthase, normally condenses two ALA molecules to form PBG in the cytosolic part of the heme biosynthetic pathway. Profound ALAD deficiency blocks this second heme-biosynthesis step.
hepatocyte link
ALAD link
heme biosynthetic process link ↓ DECREASED
porphobilinogen synthase activity link ↓ DECREASED
liver link
Show evidence (2 references)
PMID:35991568 SUPPORT Human Clinical
"Introduction: 5-Aminolevulinic acid dehydratase (ALAD) porphyria (ADP) is an autosomal recessive disease characterized by a profound deficiency in ALAD, the second enzyme in the heme biosynthetic pathway, and acute neurovisceral attacks with abdominal pain and peripheral neuropathy. "
This ADP case report directly places the ALAD defect at the second heme-biosynthesis step.
PMID:17236137 SUPPORT In Vitro
"PBGS, also called "delta-aminolevulinate dehydratase," is encoded by the ALAD gene and catalyzes the second step in the biosynthesis of heme. "
Biochemical evidence confirms the enzyme identity and pathway step.
Hepatic ALAS1 induction and excess ALA production
ADP is classified as an acute hepatic porphyria, and patient data show elevated circulating hepatic ALAS1 mRNA. Hepatic ALAS1 induction increases upstream pathway flux and supports the liver as an important source of excess ALA, although erythroid marrow may also contribute.
hepatocyte link
ALAS1 link
heme biosynthetic process link ↑ INCREASED
liver link
Show evidence (2 references)
PMID:33199206 SUPPORT Human Clinical
"RESULTS: Circulating hepatic 5-aminolevulinic acid synthase-1 (ALAS1) mRNA was elevated in this case, as in other AHPs. "
Direct patient evidence supports hepatic ALAS1 induction in ADP.
PMID:33199206 SUPPORT Human Clinical
"Elevation in circulating hepatic ALAS1 and response to treatment with hemin indicate that the liver is an important source of excess ALA in ADP, although the marrow may also contribute. "
This supports both hepatic source and possible erythroid contribution to ALA excess.
Hepatic and erythroid ALA accumulation without PBG overproduction
Because ALAD lies upstream of PBG, affected patients excrete large amounts of urinary ALA while lacking the PBG overproduction seen in acute intermittent porphyria. Total porphyrins, coproporphyrin III, and protoporphyrin abnormalities can also be present, contributing to abnormal porphyrin laboratory profiles and dark or purple urine.
porphyrin-containing compound metabolic process link ↑ INCREASED
Show evidence (6 references)
PMID:9516683 SUPPORT Human Clinical
"Because of an almost complete lack of ALAD activity, patients excrete a large amount of ALA, but not PBG, into urine. "
This is the defining biochemical distinction from AIP.
PMID:9732973 SUPPORT Human Clinical
"After this therapy both urinary 5-aminolevulinic acid (ALA) and total porphyrins were diminished to 65% in patient B. "
Follow-up data show urinary ALA and porphyrins as measurable disease activity markers.
PMID:10211628 SUPPORT Human Clinical
"The concentration of total coproporphyrins was about 30-fold increased in patients with ALAD deficiency porphyria and acute lead intoxication as compared with controls. "
Patient biochemical data support abnormal coproporphyrin excretion in ADP.
+ 3 more references
ALA-mediated neurovisceral attack susceptibility
Accumulation of ALA in acute hepatic porphyria causes acute neurovisceral attacks, including abdominal pain, peripheral neuropathy, muscle weakness, and sometimes respiratory insufficiency. ALAD porphyria lacks primary skin symptoms.
Show evidence (3 references)
PMID:35991568 SUPPORT Human Clinical
"Introduction: 5-Aminolevulinic acid dehydratase (ALAD) porphyria (ADP) is an autosomal recessive disease characterized by a profound deficiency in ALAD, the second enzyme in the heme biosynthetic pathway, and acute neurovisceral attacks with abdominal pain and peripheral neuropathy. "
The clinical pattern in ADP directly links ALAD deficiency to acute neurovisceral attacks.
ORPHA:100924 SUPPORT Other
"A rare acute hepatic porphyria characterized by neurovisceral attacks without skin symptoms."
Orphanet confirms neurovisceral attacks without skin symptoms.
PMID:33786855 SUPPORT Human Clinical
"Acute hepatic porphyrias are inherited metabolic disorders that may present with polyneuropathy, which if not diagnosed early can lead to quadriparesis, respiratory weakness, and death. "
Review evidence supports motor and respiratory weakness as severe downstream manifestations of acute hepatic porphyric neuropathy.

Pathograph

Use the checkboxes to hide or show graph categories. Hover nodes for evidence and cross-linked metadata.
Pathograph: causal mechanism network for Porphyria due to ALA Dehydratase Deficiency 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

11
Digestive 2
Nausea OCCASIONAL Nausea (HP:0002018)
Show evidence (1 reference)
ORPHA:100924 SUPPORT Other
"HP:0002018 | Nausea | Occasional (29-5%)"
Orphanet records nausea as occasional in ADP.
Constipation OCCASIONAL Constipation (HP:0002019)
Show evidence (1 reference)
ORPHA:100924 SUPPORT Other
"HP:0002019 | Constipation | Occasional (29-5%)"
Orphanet records constipation as occasional in ADP.
Musculoskeletal 1
Muscle weakness FREQUENT Muscle weakness (HP:0001324)
Show evidence (1 reference)
ORPHA:100924 SUPPORT Other
"HP:0001324 | Muscle weakness | Frequent (79-30%)"
Orphanet records muscle weakness as frequent in ADP.
Nervous System 1
Peripheral neuropathy FREQUENT Peripheral neuropathy (HP:0009830)
Show evidence (2 references)
ORPHA:100924 SUPPORT Other
"HP:0009830 | Peripheral neuropathy | Frequent (79-30%)"
Orphanet records peripheral neuropathy as frequent in ADP.
PMID:35991568 SUPPORT Human Clinical
"Introduction: 5-Aminolevulinic acid dehydratase (ALAD) porphyria (ADP) is an autosomal recessive disease characterized by a profound deficiency in ALAD, the second enzyme in the heme biosynthetic pathway, and acute neurovisceral attacks with abdominal pain and peripheral neuropathy. "
This ADP case report identifies peripheral neuropathy as part of attacks.
Respiratory 1
Respiratory insufficiency OCCASIONAL Respiratory insufficiency (HP:0002093)
Show evidence (1 reference)
ORPHA:100924 SUPPORT Other
"HP:0002093 | Respiratory insufficiency | Occasional (29-5%)"
Orphanet records respiratory insufficiency as occasional in ADP.
Constitutional 1
Abdominal pain FREQUENT Abdominal pain (HP:0002027)
Show evidence (2 references)
ORPHA:100924 SUPPORT Other
"HP:0002027 | Abdominal pain | Frequent (79-30%)"
Orphanet records abdominal pain as frequent in ADP.
PMID:35991568 SUPPORT Human Clinical
"Introduction: 5-Aminolevulinic acid dehydratase (ALAD) porphyria (ADP) is an autosomal recessive disease characterized by a profound deficiency in ALAD, the second enzyme in the heme biosynthetic pathway, and acute neurovisceral attacks with abdominal pain and peripheral neuropathy. "
Patient-level ADP evidence identifies abdominal pain during neurovisceral attacks.
Other 5
Purple urine FREQUENT Purple urine (HP:0040322)
Show evidence (1 reference)
ORPHA:100924 SUPPORT Other
"HP:0040322 | Purple urine | Frequent (79-30%)"
Orphanet records purple urine as frequent in ADP.
Abnormal circulating porphyrin concentration FREQUENT Abnormal circulating porphyrin concentration (HP:0010472)
Show evidence (1 reference)
ORPHA:100924 SUPPORT Other
"HP:0010472 | Abnormal circulating porphyrin concentration | Frequent (79-30%)"
Orphanet records abnormal porphyrin concentration as frequent in ADP.
Increased erythrocyte protoporphyrin concentration FREQUENT Increased erythrocyte protoporphyrin concentration (HP:0012187)
Show evidence (1 reference)
ORPHA:100924 SUPPORT Other
"HP:0012187 | Increased erythrocyte protoporphyrin concentration | Frequent (79-30%)"
Orphanet records increased erythrocyte protoporphyrin concentration as frequent in ADP.
Increased fecal coproporphyrin 3 FREQUENT Increased fecal coproporphyrin 3 (HP:0033010)
Show evidence (1 reference)
ORPHA:100924 SUPPORT Other
"HP:0033010 | Increased fecal coproporphyrin 3 | Frequent (79-30%)"
Orphanet records increased fecal coproporphyrin 3 as frequent in ADP.
Reduced erythrocyte ALAD activity FREQUENT Abnormal erythrocyte enzyme concentration or activity (HP:0030272)
Show evidence (2 references)
ORPHA:100924 SUPPORT Other
"HP:0030272 | Abnormal erythrocyte enzyme activity | Frequent (79-30%)"
Orphanet records abnormal erythrocyte enzyme activity as frequent in ADP.
PMID:9732973 SUPPORT Human Clinical
"The patients' enzyme activity was <10% from 1977 to 1997. "
Longitudinal patient data directly document severely reduced ALAD activity.
🧬

Genetic Associations

1
ALAD pathogenic variants (Causative)
Autosomal recessive
Show evidence (3 references)
PMID:16343966 SUPPORT Human Clinical
"This case represents the molecular analysis of the ALAD gene defects in the first case of ADP identified in North America, who is a compound heterozygote for two novel ALAD gene defects. "
This directly supports compound heterozygous ALAD variants as causative.
PMID:41268747 SUPPORT Human Clinical
"These findings underscore the molecular heterogeneity of the ALAD gene and present the first reported case of ADP in a female patient. "
Recent patient data broaden the molecular and sex representation of reported genetic ADP cases.
"ALAD | HGNC:395 | porphyria due to ALA dehydratase deficiency | MONDO:0013000 | AR | Moderate"
ClinGen classifies the ALAD-porphyria due to ALA dehydratase deficiency gene-disease relationship as moderate with autosomal recessive inheritance.
💊

Treatments

4
Intravenous hemin or heme arginate for acute attacks
Action: Pharmacotherapy NCIT:C15986
Agent: hemin
Intravenous hemin or heme arginate is the best documented attack-directed therapy in ADP. Clinical benefit supports hepatic ALAS1 repression and reduction of ALA production as the main therapeutic mechanism.
Mechanism Target:
INHIBITS Hepatic ALAS1 induction and excess ALA production — Heme therapy represses hepatic ALAS1 and reduces the upstream ALA burden.
Show evidence (1 reference)
PMID:33199206 SUPPORT Human Clinical
"Elevation in circulating hepatic ALAS1 and response to treatment with hemin indicate that the liver is an important source of excess ALA in ADP, although the marrow may also contribute. "
ADP patient data link hemin response to hepatic ALAS1-associated ALA production.
INHIBITS Hepatic and erythroid ALA accumulation without PBG overproduction — Heme arginate plus glucose lowers urinary ALA and total porphyrins in documented ADP crises.
Show evidence (1 reference)
PMID:9732973 SUPPORT Human Clinical
"After this therapy both urinary 5-aminolevulinic acid (ALA) and total porphyrins were diminished to 65% in patient B. "
Longitudinal ADP treatment data show biochemical improvement after heme arginate and glucose.
Show evidence (2 references)
PMID:33199206 SUPPORT Human Clinical
"Intravenous hemin was effective in most reported cases for treatment and prevention of acute attacks of neurological symptoms. "
Review of documented ADP cases supports intravenous hemin for attack treatment and prevention.
PMID:35991568 SUPPORT Human Clinical
"Hemin infusions are often effective in treating and preventing such attacks. "
The 2022 ADP case report summarizes hemin as an often-effective attack therapy.
Glucose infusion or carbohydrate loading
Action: dietary intervention MAXO:0000088
Agent: glucose
Glucose infusion has been used with heme arginate during acute ADP crises, but available evidence supports it as adjunctive rather than definitive therapy.
Show evidence (1 reference)
PMID:9732973 SUPPORT Human Clinical
"An acute crisis in each patient was successfully treated by infusion of glucose and heme arginate. "
Long-term ADP follow-up documents glucose used with heme arginate in successful crisis treatment.
Givosiran not established for ADP
Action: Pharmacotherapy NCIT:C15986
Agent: givosiran
Givosiran is approved for recurrent acute hepatic porphyria attacks, but the published ADP experience in one patient reported continued attacks and only transient ALA decreases related to rescue hemin. The treatment remains uncertain for ADP specifically.
Show evidence (1 reference)
PMID:35991568 SUPPORT Human Clinical
"The patient has continued to have recurrent attacks, with transient decreases in ALA levels only as related to treatment of his attacks with hemin. "
This patient-level report cautions against assuming givosiran efficacy in ADP.
Hydroxyurea as experimental erythroid-directed option
Action: Pharmacotherapy NCIT:C15986
Agent: hydroxyurea
Hydroxyurea has only case-level rationale in ADP. It may be considered investigational when an erythropoietic contribution is suspected, but there is no controlled evidence base.
Show evidence (1 reference)
PMID:35991568 PARTIAL Human Clinical
"Since ADP may have an erythropoietic component, treatment with hydroxyurea, which was beneficial in one previous case, is planned. "
This supports hydroxyurea only as a limited case-level/experimental option, not established therapy.
🔬

Biochemical Markers

4
Urinary 5-aminolevulinic acid (INCREASED)
Context: Urinary ALA is markedly increased because the ALAD block prevents efficient conversion of ALA to PBG.
Pathograph Readouts
Readout Of Hepatic and erythroid ALA accumulation without PBG overproduction Positive Diagnostic
Increased urinary ALA reports the ALA-accumulation branch downstream of the ALAD enzymatic block.
Show evidence (1 reference)
PMID:9516683 SUPPORT Human Clinical
"Because of an almost complete lack of ALAD activity, patients excrete a large amount of ALA, but not PBG, into urine. "
The ADP review directly supports urinary ALA as the diagnostic readout of ALA accumulation without PBG overproduction.
Show evidence (1 reference)
PMID:9516683 SUPPORT Human Clinical
"Because of an almost complete lack of ALAD activity, patients excrete a large amount of ALA, but not PBG, into urine. "
This directly supports increased urinary ALA and distinguishes ADP from AIP.
Urinary porphobilinogen (NOT_INCREASED)
Context: Unlike most other acute hepatic porphyrias, ADP does not cause PBG overproduction because the enzymatic block is upstream of PBG formation.
Pathograph Readouts
Readout Of ALAD block in heme biosynthesis Present Absent Diagnostic
Lack of urinary PBG overproduction reports that the heme-biosynthesis block lies upstream of PBG formation, distinguishing ADP from AIP.
Show evidence (1 reference)
PMID:9516683 SUPPORT Human Clinical
"The symptoms in this disease are similar to those seen in AIP, but ALAD porphyria can be differentiated from AIP by its autosomal recessive, rather than dominant, inheritance, by the lack of PBG overproduction, and by markedly decreased ALAD activity. "
This review identifies absent PBG overproduction as a diagnostic discriminator of the ALAD block.
Show evidence (1 reference)
PMID:9516683 SUPPORT Human Clinical
"Because of an almost complete lack of ALAD activity, patients excrete a large amount of ALA, but not PBG, into urine. "
This supports the lack of PBG overproduction as a distinguishing ADP biomarker.
Erythrocyte ALAD activity (DECREASED)
Context: Erythrocyte ALAD activity is profoundly reduced in documented genetic ADP cases and can help confirm the diagnosis.
Pathograph Readouts
Readout Of ALAD block in heme biosynthesis Negative Diagnostic
Markedly reduced erythrocyte ALAD activity directly reports the deficient porphobilinogen synthase step in heme biosynthesis.
Show evidence (1 reference)
PMID:10706561 SUPPORT Human Clinical
"These data thus demonstrate that the proband was associated with 2 novel molecular defects of the ALAD gene, 1 in each allele, and account for the extremely low ALAD activity in his erythrocytes ( approximately 1% of normal). "
Patient molecular and enzyme data support erythrocyte ALAD activity as a direct readout of the heme-biosynthesis block.
Show evidence (1 reference)
PMID:10706561 SUPPORT Human Clinical
"These data thus demonstrate that the proband was associated with 2 novel molecular defects of the ALAD gene, 1 in each allele, and account for the extremely low ALAD activity in his erythrocytes ( approximately 1% of normal). "
Patient molecular and enzyme data directly document very low erythrocyte activity.
Urinary coproporphyrins (INCREASED)
Context: Urinary coproporphyrin isomers are elevated in ADP and can overlap with the biochemical pattern of acquired ALAD inhibition from lead intoxication.
Pathograph Readouts
Readout Of Hepatic and erythroid ALA accumulation without PBG overproduction Positive Diagnostic
Increased urinary coproporphyrins report the abnormal porphyrin-intermediate profile downstream of ALAD deficiency.
Show evidence (1 reference)
PMID:10211628 SUPPORT Human Clinical
"The concentration of total coproporphyrins was about 30-fold increased in patients with ALAD deficiency porphyria and acute lead intoxication as compared with controls. "
Patient biochemical data support urinary coproporphyrins as a readout of the abnormal porphyrin profile in ADP.
Show evidence (1 reference)
PMID:10211628 SUPPORT Human Clinical
"The concentration of total coproporphyrins was about 30-fold increased in patients with ALAD deficiency porphyria and acute lead intoxication as compared with controls. "
Patient biochemical data document elevated urinary coproporphyrins.
🔀

Differential Diagnoses

3

Conditions with similar clinical presentations that must be differentiated from Porphyria due to ALA Dehydratase Deficiency:

Overlapping Features AIP causes similar neurovisceral attacks but is autosomal dominant and characterized by PBG overproduction, while ALAD porphyria is autosomal recessive with markedly decreased ALAD activity and little or no PBG overproduction.
Show evidence (1 reference)
PMID:9516683 SUPPORT Human Clinical
"The symptoms in this disease are similar to those seen in AIP, but ALAD porphyria can be differentiated from AIP by its autosomal recessive, rather than dominant, inheritance, by the lack of PBG overproduction, and by markedly decreased ALAD activity. "
This directly supports AIP as the key clinical and biochemical differential.
Overlapping Features Lead intoxication can inhibit ALAD and mimic aspects of ADP biochemistry, including increased ALA and coproporphyrins. Exposure history and genetic testing help distinguish acquired inhibition from inherited ADP.
Show evidence (1 reference)
PMID:10211628 SUPPORT Human Clinical
"These results demonstrate that oral ALA loading can be used as an in vivo model to study the metabolism of the four urinary coproporphyrin isomers I-IV especially in ALAD deficiency porphyria and in acute lead poisoning. "
This supports lead intoxication as a biochemical mimic and comparator for ALAD inhibition.
Overlapping Features Tyrosinemia type I can mimic acute porphyria biochemically and clinically because succinylacetone, an abnormal tyrosine-catabolism metabolite, inhibits ALAD and causes excessive urinary ALA without inherited ALAD variants.
Show evidence (2 references)
PMID:6826727 SUPPORT Human Clinical
"It is known that patients with this hereditary disease excrete excessive amounts of delta-aminolevulinic acid (ALA) in urine and that certain patients have an accompanying clinical syndrome resembling that of acute intermittent porphyria (AIP). "
Patient observations support tyrosinemia type I as an acute-porphyria mimic.
PMID:6826727 SUPPORT In Vitro
"Our data indicate that succinylacetone is an extremely potent competitive inhibitor of ALA dehydratase in human as well as in animal tissues. "
Biochemical enzyme data support succinylacetone-mediated ALAD inhibition as the mimic mechanism.
🔬

Clinical Trials

1
NCT03338816 PHASE_III COMPLETED
ENVISION was the pivotal phase III study of givosiran in acute hepatic porphyrias. It is relevant background for givosiran exposure in the AHP class, but published ADP-specific case evidence does not establish efficacy.
Show evidence (1 reference)
clinicaltrials:NCT03338816 SUPPORT Human Clinical
"The purpose of this study is to evaluate the effect of subcutaneous givosiran (ALN-AS1), compared to placebo, on the rate of porphyria attacks in patients with Acute Hepatic Porphyrias (AHP). "
ClinicalTrials.gov documents the general AHP givosiran trial that motivated ADP use, while the treatment entry separately captures ADP-specific uncertainty.
{ }

Source YAML

click to show
name: Porphyria due to ALA Dehydratase Deficiency
category: Mendelian
creation_date: '2026-05-05T09:35:36Z'
updated_date: '2026-05-21T06:40:48Z'
description: >
  Porphyria due to ALA dehydratase deficiency, also called ALAD porphyria or
  porphyria of Doss, is an ultra-rare autosomal recessive acute hepatic
  porphyria caused by severe aminolevulinate dehydratase / porphobilinogen
  synthase deficiency. The block occurs at the second step of heme
  biosynthesis, so affected patients accumulate 5-aminolevulinic acid (ALA)
  with little or no porphobilinogen (PBG) overproduction. Clinically, the
  disorder causes recurrent neurovisceral attacks with abdominal pain,
  peripheral neuropathy, muscle weakness, and no blistering photosensitivity.
  Hemin or heme arginate with glucose is the main documented attack treatment;
  givosiran efficacy remains uncertain in this specific ultra-rare subtype.
disease_term:
  preferred_term: porphyria due to ALA dehydratase deficiency
  term:
    id: MONDO:0013000
    label: porphyria due to ALA dehydratase deficiency
synonyms:
- ALAD porphyria
- Porphyria due to ALAD deficiency
- Porphyria due to delta-aminolevulinate dehydratase deficiency
- Porphyria of Doss
parents:
- Acute Hepatic Porphyria
- Inborn Error of Heme Biosynthesis
notes: >
  ORPHA:100924 includes broad frequent terms for abnormal nervous system and
  abnormal enzyme/coenzyme activity; this entry models those with more specific
  neuropathy, weakness, and reduced erythrocyte ALAD activity terms. ORPHA also
  lists increased urinary porphobilinogen, but PMID:9516683 states that ADP
  patients excrete large amounts of ALA "but not PBG"; the biochemical section
  therefore models urinary PBG as not increased.
references:
- reference: ORPHA:100924
  title: Porphyria due to ALA dehydratase deficiency
  findings:
  - statement: Orphanet defines ALAD porphyria as an acute hepatic porphyria without skin symptoms.
    supporting_text: A rare acute hepatic porphyria characterized by neurovisceral attacks without skin symptoms.
    evidence:
    - reference: ORPHA:100924
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "A rare acute hepatic porphyria characterized by neurovisceral attacks without skin symptoms."
      explanation: Orphanet provides the core disease definition.
- reference: PMID:9516683
  title: ALAD porphyria.
  findings:
  - statement: ALAD porphyria differs biochemically from AIP because ALA, but not PBG, is overproduced.
    supporting_text: >
      Because of an almost complete lack of ALAD activity, patients excrete a
      large amount of ALA, but not PBG, into urine.
    evidence:
    - reference: PMID:9516683
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >
        Because of an almost complete lack of ALAD activity, patients excrete a
        large amount of ALA, but not PBG, into urine.
      explanation: This review summarizes the distinguishing diagnostic biochemical pattern of ADP.
- reference: PMID:33199206
  title: "5-Aminolevulinate dehydratase porphyria: Update on hepatic 5-aminolevulinic acid synthase induction and long-term response to hemin."
  findings:
  - statement: Hepatic ALAS1 induction and hemin response support a hepatic source of excess ALA in ADP.
    supporting_text: >
      Elevation in circulating hepatic ALAS1 and response to treatment with
      hemin indicate that the liver is an important source of excess ALA in
      ADP, although the marrow may also contribute.
    evidence:
    - reference: PMID:33199206
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >
        Elevation in circulating hepatic ALAS1 and response to treatment with
        hemin indicate that the liver is an important source of excess ALA in
        ADP, although the marrow may also contribute.
      explanation: This patient update links hepatic ALAS1 induction, excess ALA production, and hemin responsiveness.
- reference: PMID:33786855
  title: Porphyric neuropathy.
  findings:
  - statement: Acute hepatic porphyria neuropathy can progress to quadriparesis and respiratory weakness.
    supporting_text: >
      Acute hepatic porphyrias are inherited metabolic disorders that may present
      with polyneuropathy, which if not diagnosed early can lead to quadriparesis,
      respiratory weakness, and death.
    evidence:
    - reference: PMID:33786855
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >
        Acute hepatic porphyrias are inherited metabolic disorders that may
        present with polyneuropathy, which if not diagnosed early can lead to
        quadriparesis, respiratory weakness, and death.
      explanation: ADP is an acute hepatic porphyria, so this review supports neuropathic weakness and respiratory weakness as severe downstream attack manifestations.
- reference: PMID:6826727
  title: Hereditary tyrosinemia and the heme biosynthetic pathway. Profound inhibition of delta-aminolevulinic acid dehydratase activity by succinylacetone.
  findings:
  - statement: Hereditary tyrosinemia type I can mimic acute porphyria through succinylacetone-mediated ALAD inhibition.
    supporting_text: >
      Patients with hereditary tyrosinemia can excrete excessive urinary ALA
      and develop a syndrome resembling acute intermittent porphyria, while
      succinylacetone competitively inhibits ALA dehydratase.
    evidence:
    - reference: PMID:6826727
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >
        It is known that patients with this hereditary disease excrete
        excessive amounts of delta-aminolevulinic acid (ALA) in urine and that
        certain patients have an accompanying clinical syndrome resembling that
        of acute intermittent porphyria (AIP).
      explanation: Patient observations support tyrosinemia type I as an acute-porphyria mimic.
    - reference: PMID:6826727
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: >
        Our data indicate that succinylacetone is an extremely potent
        competitive inhibitor of ALA dehydratase in human as well as in animal
        tissues.
      explanation: Biochemical enzyme data support succinylacetone-mediated ALAD inhibition as the mimic mechanism.
- reference: DOI:10.1002/0471142905.hg1720s86
  title: "Porphyria Diagnostics-Part 1: A Brief Overview of the Porphyrias"
  found_in:
  - Porphyria_due_to_ALA_Dehydratase_Deficiency-deep-research-falcon.md
- reference: DOI:10.1023/b:boli.0000037341.21975.9d
  title: "The third case of Doss porphyria (delta-aminolevulinic acid dehydratase deficiency) in Germany"
  found_in:
  - Porphyria_due_to_ALA_Dehydratase_Deficiency-deep-research-falcon.md
- reference: DOI:10.1053/j.gastro.2022.11.034
  title: "AGA Clinical Practice Update on Diagnosis and Management of Acute Hepatic Porphyrias: Expert Review"
  found_in:
  - Porphyria_due_to_ALA_Dehydratase_Deficiency-deep-research-falcon.md
- reference: DOI:10.1055/s-0043-1776760
  title: "The Hepatic Porphyrias: Revealing the Complexities of a Rare Disease"
  found_in:
  - Porphyria_due_to_ALA_Dehydratase_Deficiency-deep-research-falcon.md
- reference: DOI:10.1093/clinchem/44.9.1892
  title: "5-Aminolevulinic acid dehydratase deficiency porphyria: a twenty-year clinical and biochemical follow-up"
  found_in:
  - Porphyria_due_to_ALA_Dehydratase_Deficiency-deep-research-falcon.md
- reference: DOI:10.1136/bmjgast-2024-icpp.75
  title: "Functional characterization of new pathogenic and lead-poisoning predisposing variants in ALA Dehydratase Porphyria"
  found_in:
  - Porphyria_due_to_ALA_Dehydratase_Deficiency-deep-research-falcon.md
- reference: DOI:10.3389/fgene.2022.867856
  title: "Case Report: Lack of Response to Givosiran in a Case of ALAD Porphyria"
  found_in:
  - Porphyria_due_to_ALA_Dehydratase_Deficiency-deep-research-falcon.md
- reference: DOI:10.3390/diagnostics11081343
  title: "Laboratory Diagnosis of Porphyria"
  found_in:
  - Porphyria_due_to_ALA_Dehydratase_Deficiency-deep-research-falcon.md
prevalence:
- population: Europe
  percentage: Less than 1 per 1,000,000
  notes: >
    Orphanet reports European point prevalence below one per million for this
    ultra-rare porphyria subtype.
  evidence:
  - reference: ORPHA:100924
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "<1 / 1 000 000 | Europe | Point prevalence | ORPHANET"
    explanation: Orphanet reports a very low European point prevalence.
inheritance:
- name: Autosomal recessive
  inheritance_term:
    preferred_term: Autosomal recessive inheritance
    term:
      id: HP:0000007
      label: Autosomal recessive inheritance
  description: >
    ALAD porphyria is an autosomal recessive disorder usually caused by
    biallelic ALAD variants that leave very low residual enzyme activity.
  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 ADP clinical update directly states autosomal recessive inheritance.
  - reference: ORPHA:100924
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Autosomal recessive"
    explanation: Orphanet records autosomal recessive inheritance.
progression:
- phase: Childhood or adolescent acute neurovisceral attacks
  notes: >
    Reported genetic ADP cases usually begin in childhood or adolescence with
    acute neurovisceral attacks; long-term natural history is poorly understood
    because very few patients have been documented.
  evidence:
  - reference: ORPHA:100924
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Age of onset: Childhood"
    explanation: Orphanet records childhood onset.
  - reference: ORPHA:100924
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Age of onset: Adolescent"
    explanation: Orphanet records adolescent onset.
  - 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: >
      Seven reported ADP cases had compound heterozygous ALAD mutations
      resulting in very low residual ALAD activity and symptoms early in life
      or adolescence.
    explanation: Review of documented cases supports early-life or adolescent presentation.
pathophysiology:
- name: ALAD conformational and biallelic variant defects
  description: >
    Pathogenic ALAD variants can impair porphobilinogen synthase by destabilizing
    the active octameric enzyme, shifting the morpheein equilibrium toward
    low-activity hexamers, or producing unstable or low-activity mutant proteins.
    The result is profound residual ALAD activity loss in affected patients.
  genes:
  - preferred_term: ALAD
    term:
      id: hgnc:395
      label: ALAD
    modifier: DECREASED
  molecular_functions:
  - preferred_term: porphobilinogen synthase activity
    term:
      id: GO:0004655
      label: porphobilinogen synthase activity
    modifier: DECREASED
  evidence:
  - reference: PMID:17236137
    reference_title: "ALAD porphyria is a conformational disease."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >
      Thus, all porphyria-associated human PBGS variants are found to shift the
      morpheein equilibrium for PBGS toward the less active hexamer.
    explanation: Biochemical expression work supports a conformational mechanism for multiple ALAD variants.
  - reference: PMID:16343966
    reference_title: "delta-Aminolevulinate dehydratase (ALAD) porphyria: the first case in North America with two novel ALAD mutations."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >
      These results suggest that the combination of the two aberrant ALADs with
      little enzyme activity accounts for the markedly decreased ALAD activity
      observed in the proband.
    explanation: In vitro expression of patient ALAD variants supports markedly reduced enzyme activity.
  - reference: PMID:10706561
    reference_title: "Novel molecular defects of the delta-aminolevulinate dehydratase gene in a patient with inherited acute hepatic porphyria."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >
      These data thus demonstrate that the proband was associated with 2 novel
      molecular defects of the ALAD gene, 1 in each allele, and account for the
      extremely low ALAD activity in his erythrocytes ( approximately 1% of
      normal).
    explanation: A second patient study supports biallelic ALAD defects with near-absent erythrocyte activity.
  downstream:
  - target: ALAD block in heme biosynthesis
    description: Variant-driven loss of ALAD / PBGS function blocks the second step of heme biosynthesis.
    causal_link_type: DIRECT
  - target: Reduced erythrocyte ALAD activity
    description: Biallelic ALAD defects manifest as markedly reduced erythrocyte ALAD enzyme activity.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:9732973
      reference_title: "5-Aminolevulinic acid dehydratase deficiency porphyria: a twenty-year clinical and biochemical follow-up."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "The patients' enzyme activity was <10% from 1977 to 1997."
      explanation: Longitudinal patient data directly document severely reduced ALAD enzyme activity.
    - reference: PMID:10706561
      reference_title: "Novel molecular defects of the delta-aminolevulinate dehydratase gene in a patient with inherited acute hepatic porphyria."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >
        These data thus demonstrate that the proband was associated with 2 novel
        molecular defects of the ALAD gene, 1 in each allele, and account for the
        extremely low ALAD activity in his erythrocytes ( approximately 1% of
        normal).
      explanation: Patient molecular and enzyme data directly connect biallelic ALAD defects to extremely low erythrocyte activity.
  - target: Erythrocyte ALAD activity
    description: Molecular ALAD defects account for extremely low erythrocyte ALAD activity.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:10706561
      reference_title: "Novel molecular defects of the delta-aminolevulinate dehydratase gene in a patient with inherited acute hepatic porphyria."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >
        These data thus demonstrate that the proband was associated with 2 novel
        molecular defects of the ALAD gene, 1 in each allele, and account for the
        extremely low ALAD activity in his erythrocytes ( approximately 1% of
        normal).
      explanation: Patient molecular and enzyme data connect biallelic ALAD defects to the biochemical enzyme-activity readout.
- name: ALAD block in heme biosynthesis
  description: >
    ALAD, also known as porphobilinogen synthase, normally condenses two ALA
    molecules to form PBG in the cytosolic part of the heme biosynthetic pathway.
    Profound ALAD deficiency blocks this second heme-biosynthesis step.
  genes:
  - preferred_term: ALAD
    term:
      id: hgnc:395
      label: ALAD
    modifier: DECREASED
  biological_processes:
  - preferred_term: heme biosynthetic process
    term:
      id: GO:0006783
      label: heme biosynthetic process
    modifier: DECREASED
  molecular_functions:
  - preferred_term: porphobilinogen synthase activity
    term:
      id: GO:0004655
      label: porphobilinogen synthase activity
    modifier: DECREASED
  cell_types:
  - preferred_term: hepatocyte
    term:
      id: CL:0000182
      label: hepatocyte
  locations:
  - preferred_term: liver
    term:
      id: UBERON:0002107
      label: liver
  evidence:
  - reference: PMID:35991568
    reference_title: "Case Report: Lack of Response to Givosiran in a Case of ALAD Porphyria."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >
      Introduction: 5-Aminolevulinic acid dehydratase (ALAD) porphyria (ADP)
      is an autosomal recessive disease characterized by a profound deficiency
      in ALAD, the second enzyme in the heme biosynthetic pathway, and acute
      neurovisceral attacks with abdominal pain and peripheral neuropathy.
    explanation: This ADP case report directly places the ALAD defect at the second heme-biosynthesis step.
  - reference: PMID:17236137
    reference_title: "ALAD porphyria is a conformational disease."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >
      PBGS, also called "delta-aminolevulinate dehydratase," is encoded by the
      ALAD gene and catalyzes the second step in the biosynthesis of heme.
    explanation: Biochemical evidence confirms the enzyme identity and pathway step.
  downstream:
  - target: Hepatic and erythroid ALA accumulation without PBG overproduction
    description: The enzymatic block prevents efficient conversion of ALA to PBG, causing ALA excess with little PBG overproduction.
    causal_link_type: DIRECT
  - target: Urinary porphobilinogen
    description: Because the ALAD block lies upstream of PBG formation, ADP lacks the urinary PBG overproduction typical of AIP.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:9516683
      reference_title: "ALAD porphyria."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >
        Because of an almost complete lack of ALAD activity, patients excrete a
        large amount of ALA, but not PBG, into urine.
      explanation: ADP review evidence directly supports absent or non-increased urinary PBG despite excess ALA.
- name: Hepatic ALAS1 induction and excess ALA production
  description: >
    ADP is classified as an acute hepatic porphyria, and patient data show
    elevated circulating hepatic ALAS1 mRNA. Hepatic ALAS1 induction increases
    upstream pathway flux and supports the liver as an important source of
    excess ALA, although erythroid marrow may also contribute.
  genes:
  - preferred_term: ALAS1
    term:
      id: hgnc:396
      label: ALAS1
    modifier: INCREASED
  biological_processes:
  - preferred_term: heme biosynthetic process
    term:
      id: GO:0006783
      label: heme biosynthetic process
    modifier: INCREASED
  cell_types:
  - preferred_term: hepatocyte
    term:
      id: CL:0000182
      label: hepatocyte
  locations:
  - preferred_term: liver
    term:
      id: UBERON:0002107
      label: liver
  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: >
      RESULTS: Circulating hepatic 5-aminolevulinic acid synthase-1 (ALAS1)
      mRNA was elevated in this case, as in other AHPs.
    explanation: Direct patient evidence supports hepatic ALAS1 induction in ADP.
  - 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: >
      Elevation in circulating hepatic ALAS1 and response to treatment with
      hemin indicate that the liver is an important source of excess ALA in
      ADP, although the marrow may also contribute.
    explanation: This supports both hepatic source and possible erythroid contribution to ALA excess.
  downstream:
  - target: Hepatic and erythroid ALA accumulation without PBG overproduction
    description: Increased upstream synthesis feeds into the ALAD block and raises ALA levels.
    causal_link_type: DIRECT
- name: Hepatic and erythroid ALA accumulation without PBG overproduction
  description: >
    Because ALAD lies upstream of PBG, affected patients excrete large amounts
    of urinary ALA while lacking the PBG overproduction seen in acute
    intermittent porphyria. Total porphyrins, coproporphyrin III, and
    protoporphyrin abnormalities can also be present, contributing to abnormal
    porphyrin laboratory profiles and dark or purple urine.
  biological_processes:
  - preferred_term: porphyrin-containing compound metabolic process
    term:
      id: GO:0006778
      label: porphyrin-containing compound metabolic process
    modifier: INCREASED
  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
  - preferred_term: coproporphyrin III
    term:
      id: CHEBI:27609
      label: coproporphyrin III
    modifier: INCREASED
  - preferred_term: protoporphyrin
    term:
      id: CHEBI:15430
      label: protoporphyrin
    modifier: INCREASED
  evidence:
  - reference: PMID:9516683
    reference_title: "ALAD porphyria."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >
      Because of an almost complete lack of ALAD activity, patients excrete a
      large amount of ALA, but not PBG, into urine.
    explanation: This is the defining biochemical distinction from AIP.
  - reference: PMID:9732973
    reference_title: "5-Aminolevulinic acid dehydratase deficiency porphyria: a twenty-year clinical and biochemical follow-up."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >
      After this therapy both urinary 5-aminolevulinic acid (ALA) and total
      porphyrins were diminished to 65% in patient B.
    explanation: Follow-up data show urinary ALA and porphyrins as measurable disease activity markers.
  - reference: PMID:10211628
    reference_title: "Investigations on the formation of urinary coproporphyrin isomers I-IV in 5-aminolevulinic acid dehydratase deficiency porphyria, acute lead intoxication and after oral 5-aminolevulinic acid loading."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >
      The concentration of total coproporphyrins was about 30-fold increased in
      patients with ALAD deficiency porphyria and acute lead intoxication as
      compared with controls.
    explanation: Patient biochemical data support abnormal coproporphyrin excretion in ADP.
  - reference: ORPHA:100924
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0010472 | Abnormal circulating porphyrin concentration | Frequent (79-30%)"
    explanation: Orphanet records abnormal porphyrin concentration as a frequent ADP phenotype.
  - reference: ORPHA:100924
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0012187 | Increased erythrocyte protoporphyrin concentration | Frequent (79-30%)"
    explanation: Orphanet records increased erythrocyte protoporphyrin as a frequent ADP phenotype.
  - reference: ORPHA:100924
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0033010 | Increased fecal coproporphyrin 3 | Frequent (79-30%)"
    explanation: Orphanet records increased fecal coproporphyrin 3 as a frequent ADP phenotype.
  downstream:
  - target: ALA-mediated neurovisceral attack susceptibility
    description: ALA excess is linked to recurrent abdominal pain, neuropathy, and weakness during attacks.
    causal_link_type: DIRECT
  - target: Urinary 5-aminolevulinic acid
    description: ALAD deficiency causes excessive urinary ALA excretion.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:9516683
      reference_title: "ALAD porphyria."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >
        Because of an almost complete lack of ALAD activity, patients excrete a
        large amount of ALA, but not PBG, into urine.
      explanation: ADP review evidence directly links ALAD activity loss to large urinary ALA excretion.
  - target: Urinary coproporphyrins
    description: ALAD deficiency is associated with markedly increased urinary total coproporphyrins.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:10211628
      reference_title: "Investigations on the formation of urinary coproporphyrin isomers I-IV in 5-aminolevulinic acid dehydratase deficiency porphyria, acute lead intoxication and after oral 5-aminolevulinic acid loading."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >
        The concentration of total coproporphyrins was about 30-fold increased in
        patients with ALAD deficiency porphyria and acute lead intoxication as
        compared with controls.
      explanation: Patient biochemical data directly connect ALAD deficiency porphyria to elevated urinary coproporphyrins.
  - target: Abnormal circulating porphyrin concentration
    description: Porphyrin-pathway intermediate accumulation produces an abnormal porphyrin biochemical profile in ADP.
    causal_link_type: DIRECT
    evidence:
    - reference: ORPHA:100924
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "HP:0010472 | Abnormal circulating porphyrin concentration | Frequent (79-30%)"
      explanation: Orphanet records abnormal porphyrin concentration as frequent in ADP.
  - target: Purple urine
    description: Urinary porphyrin-pathway intermediate accumulation can manifest clinically as purple or dark urine.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - urinary porphyrin-pathway intermediate accumulation and oxidation
    evidence:
    - reference: ORPHA:100924
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "HP:0040322 | Purple urine | Frequent (79-30%)"
      explanation: Orphanet records purple urine as frequent in ADP.
    - reference: PMID:9732973
      reference_title: "5-Aminolevulinic acid dehydratase deficiency porphyria: a twenty-year clinical and biochemical follow-up."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >
        After this therapy both urinary 5-aminolevulinic acid (ALA) and total
        porphyrins were diminished to 65% in patient B.
      explanation: Longitudinal ADP data document urinary porphyrins as disease-activity markers, supporting the urinary pigment intermediate.
  - target: Increased erythrocyte protoporphyrin concentration
    description: ADP is associated with erythrocyte protoporphyrin elevation, although the exact intermediate steps are not resolved here.
    causal_link_type: UNKNOWN
    evidence:
    - reference: ORPHA:100924
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "HP:0012187 | Increased erythrocyte protoporphyrin concentration | Frequent (79-30%)"
      explanation: Orphanet records increased erythrocyte protoporphyrin concentration as frequent in ADP.
  - target: Increased fecal coproporphyrin 3
    description: ADP is associated with increased fecal coproporphyrin 3, but the exact causal path from the ALAD block is not specified in cached evidence.
    causal_link_type: UNKNOWN
    evidence:
    - reference: ORPHA:100924
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "HP:0033010 | Increased fecal coproporphyrin 3 | Frequent (79-30%)"
      explanation: Orphanet records increased fecal coproporphyrin 3 as frequent in ADP.
- name: ALA-mediated neurovisceral attack susceptibility
  description: >
    Accumulation of ALA in acute hepatic porphyria causes acute neurovisceral
    attacks, including abdominal pain, peripheral neuropathy, muscle weakness,
    and sometimes respiratory insufficiency. ALAD porphyria lacks primary skin
    symptoms.
  evidence:
  - reference: PMID:35991568
    reference_title: "Case Report: Lack of Response to Givosiran in a Case of ALAD Porphyria."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >
      Introduction: 5-Aminolevulinic acid dehydratase (ALAD) porphyria (ADP)
      is an autosomal recessive disease characterized by a profound deficiency
      in ALAD, the second enzyme in the heme biosynthetic pathway, and acute
      neurovisceral attacks with abdominal pain and peripheral neuropathy.
    explanation: The clinical pattern in ADP directly links ALAD deficiency to acute neurovisceral attacks.
  - reference: ORPHA:100924
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "A rare acute hepatic porphyria characterized by neurovisceral attacks without skin symptoms."
    explanation: Orphanet confirms neurovisceral attacks without skin symptoms.
  - reference: PMID:33786855
    reference_title: "Porphyric neuropathy."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >
      Acute hepatic porphyrias are inherited metabolic disorders that may
      present with polyneuropathy, which if not diagnosed early can lead to
      quadriparesis, respiratory weakness, and death.
    explanation: Review evidence supports motor and respiratory weakness as severe downstream manifestations of acute hepatic porphyric neuropathy.
  downstream:
  - target: Abdominal pain
    description: ADP neurovisceral attacks include abdominal pain.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:35991568
      reference_title: "Case Report: Lack of Response to Givosiran in a Case of ALAD Porphyria."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >
        Introduction: 5-Aminolevulinic acid dehydratase (ALAD) porphyria (ADP)
        is an autosomal recessive disease characterized by a profound deficiency
        in ALAD, the second enzyme in the heme biosynthetic pathway, and acute
        neurovisceral attacks with abdominal pain and peripheral neuropathy.
      explanation: ADP case-report evidence directly identifies abdominal pain as part of neurovisceral attacks.
  - target: Peripheral neuropathy
    description: ADP neurovisceral attacks include peripheral neuropathy.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:35991568
      reference_title: "Case Report: Lack of Response to Givosiran in a Case of ALAD Porphyria."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >
        Introduction: 5-Aminolevulinic acid dehydratase (ALAD) porphyria (ADP)
        is an autosomal recessive disease characterized by a profound deficiency
        in ALAD, the second enzyme in the heme biosynthetic pathway, and acute
        neurovisceral attacks with abdominal pain and peripheral neuropathy.
      explanation: ADP case-report evidence directly identifies peripheral neuropathy as part of neurovisceral attacks.
  - target: Muscle weakness
    description: Motor-predominant porphyric neuropathy during severe attacks can cause generalized weakness.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - motor-predominant porphyric neuropathy
    evidence:
    - reference: ORPHA:100924
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "HP:0001324 | Muscle weakness | Frequent (79-30%)"
      explanation: Orphanet records muscle weakness as frequent in ADP.
    - reference: PMID:33786855
      reference_title: "Porphyric neuropathy."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >
        Acute hepatic porphyrias are inherited metabolic disorders that may
        present with polyneuropathy, which if not diagnosed early can lead to
        quadriparesis, respiratory weakness, and death.
      explanation: Review evidence supports weakness as a consequence of acute hepatic porphyric neuropathy.
  - target: Respiratory insufficiency
    description: Severe porphyric neuropathy can involve respiratory muscle weakness, producing respiratory insufficiency.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - porphyric neuropathy with respiratory muscle weakness
    evidence:
    - reference: ORPHA:100924
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "HP:0002093 | Respiratory insufficiency | Occasional (29-5%)"
      explanation: Orphanet records respiratory insufficiency as an occasional ADP manifestation.
    - reference: PMID:33786855
      reference_title: "Porphyric neuropathy."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >
        Acute hepatic porphyrias are inherited metabolic disorders that may
        present with polyneuropathy, which if not diagnosed early can lead to
        quadriparesis, respiratory weakness, and death.
      explanation: Review evidence supports respiratory weakness as a severe consequence of acute hepatic porphyric neuropathy.
  - target: Nausea
    description: ADP neurovisceral attacks can include nausea, but the precise intermediate mechanism is not specified in cached ADP evidence.
    causal_link_type: UNKNOWN
    evidence:
    - reference: ORPHA:100924
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "HP:0002018 | Nausea | Occasional (29-5%)"
      explanation: Orphanet records nausea as an occasional ADP manifestation.
  - target: Constipation
    description: ADP neurovisceral attacks can include constipation, but the precise intermediate mechanism is not specified in cached ADP evidence.
    causal_link_type: UNKNOWN
    evidence:
    - reference: ORPHA:100924
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "HP:0002019 | Constipation | Occasional (29-5%)"
      explanation: Orphanet records constipation as an occasional ADP manifestation.
phenotypes:
- name: Abdominal pain
  frequency: FREQUENT
  description: >
    Abdominal pain is a frequent neurovisceral manifestation during acute ADP
    attacks.
  phenotype_term:
    preferred_term: Abdominal pain
    term:
      id: HP:0002027
      label: Abdominal pain
  evidence:
  - reference: ORPHA:100924
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0002027 | Abdominal pain | Frequent (79-30%)"
    explanation: Orphanet records abdominal pain as frequent in ADP.
  - reference: PMID:35991568
    reference_title: "Case Report: Lack of Response to Givosiran in a Case of ALAD Porphyria."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >
      Introduction: 5-Aminolevulinic acid dehydratase (ALAD) porphyria (ADP)
      is an autosomal recessive disease characterized by a profound deficiency
      in ALAD, the second enzyme in the heme biosynthetic pathway, and acute
      neurovisceral attacks with abdominal pain and peripheral neuropathy.
    explanation: Patient-level ADP evidence identifies abdominal pain during neurovisceral attacks.
- name: Peripheral neuropathy
  frequency: FREQUENT
  description: >
    Peripheral neuropathy is a frequent neurologic manifestation of ADP attacks.
  phenotype_term:
    preferred_term: Peripheral neuropathy
    term:
      id: HP:0009830
      label: Peripheral neuropathy
  evidence:
  - reference: ORPHA:100924
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0009830 | Peripheral neuropathy | Frequent (79-30%)"
    explanation: Orphanet records peripheral neuropathy as frequent in ADP.
  - reference: PMID:35991568
    reference_title: "Case Report: Lack of Response to Givosiran in a Case of ALAD Porphyria."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >
      Introduction: 5-Aminolevulinic acid dehydratase (ALAD) porphyria (ADP)
      is an autosomal recessive disease characterized by a profound deficiency
      in ALAD, the second enzyme in the heme biosynthetic pathway, and acute
      neurovisceral attacks with abdominal pain and peripheral neuropathy.
    explanation: This ADP case report identifies peripheral neuropathy as part of attacks.
- name: Muscle weakness
  frequency: FREQUENT
  description: >
    Muscle weakness is a frequent manifestation of the neurologic attack
    phenotype.
  phenotype_term:
    preferred_term: Muscle weakness
    term:
      id: HP:0001324
      label: Muscle weakness
  evidence:
  - reference: ORPHA:100924
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0001324 | Muscle weakness | Frequent (79-30%)"
    explanation: Orphanet records muscle weakness as frequent in ADP.
- name: Nausea
  frequency: OCCASIONAL
  description: >
    Nausea can accompany acute neurovisceral attacks.
  phenotype_term:
    preferred_term: Nausea
    term:
      id: HP:0002018
      label: Nausea
  evidence:
  - reference: ORPHA:100924
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0002018 | Nausea | Occasional (29-5%)"
    explanation: Orphanet records nausea as occasional in ADP.
- name: Constipation
  frequency: OCCASIONAL
  description: >
    Constipation is one of the gastrointestinal symptoms reported in ADP.
  phenotype_term:
    preferred_term: Constipation
    term:
      id: HP:0002019
      label: Constipation
  evidence:
  - reference: ORPHA:100924
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0002019 | Constipation | Occasional (29-5%)"
    explanation: Orphanet records constipation as occasional in ADP.
- name: Respiratory insufficiency
  frequency: OCCASIONAL
  description: >
    Severe attacks can include respiratory insufficiency, likely through
    porphyric neuropathy affecting respiratory muscles.
  phenotype_term:
    preferred_term: Respiratory insufficiency
    term:
      id: HP:0002093
      label: Respiratory insufficiency
  evidence:
  - reference: ORPHA:100924
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0002093 | Respiratory insufficiency | Occasional (29-5%)"
    explanation: Orphanet records respiratory insufficiency as occasional in ADP.
- name: Purple urine
  frequency: FREQUENT
  description: >
    Purple or dark urine reflects accumulation and oxidation of porphyrin-pathway
    intermediates during attacks.
  phenotype_term:
    preferred_term: Purple urine
    term:
      id: HP:0040322
      label: Purple urine
  evidence:
  - reference: ORPHA:100924
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0040322 | Purple urine | Frequent (79-30%)"
    explanation: Orphanet records purple urine as frequent in ADP.
- name: Abnormal circulating porphyrin concentration
  frequency: FREQUENT
  description: >
    Abnormal circulating or excreted porphyrin-pathway intermediates are a
    frequent biochemical phenotype.
  phenotype_term:
    preferred_term: Abnormal circulating porphyrin concentration
    term:
      id: HP:0010472
      label: Abnormal circulating porphyrin concentration
  evidence:
  - reference: ORPHA:100924
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0010472 | Abnormal circulating porphyrin concentration | Frequent (79-30%)"
    explanation: Orphanet records abnormal porphyrin concentration as frequent in ADP.
- name: Increased erythrocyte protoporphyrin concentration
  frequency: FREQUENT
  description: >
    Increased erythrocyte protoporphyrin concentration is one of the porphyrin
    pathway laboratory abnormalities recorded for ADP.
  phenotype_term:
    preferred_term: Increased erythrocyte protoporphyrin concentration
    term:
      id: HP:0012187
      label: Increased erythrocyte protoporphyrin concentration
  evidence:
  - reference: ORPHA:100924
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0012187 | Increased erythrocyte protoporphyrin concentration | Frequent (79-30%)"
    explanation: Orphanet records increased erythrocyte protoporphyrin concentration as frequent in ADP.
- name: Increased fecal coproporphyrin 3
  frequency: FREQUENT
  description: >
    Fecal coproporphyrin 3 elevation is a porphyrin-profile abnormality
    reported for ADP.
  phenotype_term:
    preferred_term: Increased fecal coproporphyrin 3
    term:
      id: HP:0033010
      label: Increased fecal coproporphyrin 3
  evidence:
  - reference: ORPHA:100924
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0033010 | Increased fecal coproporphyrin 3 | Frequent (79-30%)"
    explanation: Orphanet records increased fecal coproporphyrin 3 as frequent in ADP.
- name: Reduced erythrocyte ALAD activity
  frequency: FREQUENT
  description: >
    Erythrocyte ALAD enzyme activity is markedly reduced in reported ADP cases.
  phenotype_term:
    preferred_term: Reduced erythrocyte enzyme activity
    term:
      id: HP:0030272
      label: Abnormal erythrocyte enzyme concentration or activity
  evidence:
  - reference: ORPHA:100924
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0030272 | Abnormal erythrocyte enzyme activity | Frequent (79-30%)"
    explanation: Orphanet records abnormal erythrocyte enzyme activity as frequent in ADP.
  - reference: PMID:9732973
    reference_title: "5-Aminolevulinic acid dehydratase deficiency porphyria: a twenty-year clinical and biochemical follow-up."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >
      The patients' enzyme activity was <10% from 1977 to 1997.
    explanation: Longitudinal patient data directly document severely reduced ALAD activity.
biochemical:
- name: Urinary 5-aminolevulinic acid
  presence: INCREASED
  context: >
    Urinary ALA is markedly increased because the ALAD block prevents efficient
    conversion of ALA to PBG.
  readouts:
  - target: Hepatic and erythroid ALA accumulation without PBG overproduction
    relationship: READOUT_OF
    direction: POSITIVE
    endpoint_context: DIAGNOSTIC
    interpretation: Increased urinary ALA reports the ALA-accumulation branch downstream of the ALAD enzymatic block.
    evidence:
    - reference: PMID:9516683
      reference_title: "ALAD porphyria."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >
        Because of an almost complete lack of ALAD activity, patients excrete a
        large amount of ALA, but not PBG, into urine.
      explanation: The ADP review directly supports urinary ALA as the diagnostic readout of ALA accumulation without PBG overproduction.
  evidence:
  - reference: PMID:9516683
    reference_title: "ALAD porphyria."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >
      Because of an almost complete lack of ALAD activity, patients excrete a
      large amount of ALA, but not PBG, into urine.
    explanation: This directly supports increased urinary ALA and distinguishes ADP from AIP.
- name: Urinary porphobilinogen
  presence: NOT_INCREASED
  context: >
    Unlike most other acute hepatic porphyrias, ADP does not cause PBG
    overproduction because the enzymatic block is upstream of PBG formation.
  readouts:
  - target: ALAD block in heme biosynthesis
    relationship: READOUT_OF
    direction: PRESENT_ABSENT
    endpoint_context: DIAGNOSTIC
    interpretation: Lack of urinary PBG overproduction reports that the heme-biosynthesis block lies upstream of PBG formation, distinguishing ADP from AIP.
    evidence:
    - reference: PMID:9516683
      reference_title: "ALAD porphyria."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >
        The symptoms in this disease are similar to those seen in AIP, but ALAD
        porphyria can be differentiated from AIP by its autosomal recessive,
        rather than dominant, inheritance, by the lack of PBG overproduction, and
        by markedly decreased ALAD activity.
      explanation: This review identifies absent PBG overproduction as a diagnostic discriminator of the ALAD block.
  evidence:
  - reference: PMID:9516683
    reference_title: "ALAD porphyria."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >
      Because of an almost complete lack of ALAD activity, patients excrete a
      large amount of ALA, but not PBG, into urine.
    explanation: This supports the lack of PBG overproduction as a distinguishing ADP biomarker.
- name: Erythrocyte ALAD activity
  presence: DECREASED
  context: >
    Erythrocyte ALAD activity is profoundly reduced in documented genetic ADP
    cases and can help confirm the diagnosis.
  readouts:
  - target: ALAD block in heme biosynthesis
    relationship: READOUT_OF
    direction: NEGATIVE
    endpoint_context: DIAGNOSTIC
    interpretation: Markedly reduced erythrocyte ALAD activity directly reports the deficient porphobilinogen synthase step in heme biosynthesis.
    evidence:
    - reference: PMID:10706561
      reference_title: "Novel molecular defects of the delta-aminolevulinate dehydratase gene in a patient with inherited acute hepatic porphyria."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >
        These data thus demonstrate that the proband was associated with 2 novel
        molecular defects of the ALAD gene, 1 in each allele, and account for the
        extremely low ALAD activity in his erythrocytes ( approximately 1% of
        normal).
      explanation: Patient molecular and enzyme data support erythrocyte ALAD activity as a direct readout of the heme-biosynthesis block.
  evidence:
  - reference: PMID:10706561
    reference_title: "Novel molecular defects of the delta-aminolevulinate dehydratase gene in a patient with inherited acute hepatic porphyria."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >
      These data thus demonstrate that the proband was associated with 2 novel
      molecular defects of the ALAD gene, 1 in each allele, and account for the
      extremely low ALAD activity in his erythrocytes ( approximately 1% of
      normal).
    explanation: Patient molecular and enzyme data directly document very low erythrocyte activity.
- name: Urinary coproporphyrins
  presence: INCREASED
  context: >
    Urinary coproporphyrin isomers are elevated in ADP and can overlap with the
    biochemical pattern of acquired ALAD inhibition from lead intoxication.
  readouts:
  - target: Hepatic and erythroid ALA accumulation without PBG overproduction
    relationship: READOUT_OF
    direction: POSITIVE
    endpoint_context: DIAGNOSTIC
    interpretation: Increased urinary coproporphyrins report the abnormal porphyrin-intermediate profile downstream of ALAD deficiency.
    evidence:
    - reference: PMID:10211628
      reference_title: "Investigations on the formation of urinary coproporphyrin isomers I-IV in 5-aminolevulinic acid dehydratase deficiency porphyria, acute lead intoxication and after oral 5-aminolevulinic acid loading."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >
        The concentration of total coproporphyrins was about 30-fold increased in
        patients with ALAD deficiency porphyria and acute lead intoxication as
        compared with controls.
      explanation: Patient biochemical data support urinary coproporphyrins as a readout of the abnormal porphyrin profile in ADP.
  evidence:
  - reference: PMID:10211628
    reference_title: "Investigations on the formation of urinary coproporphyrin isomers I-IV in 5-aminolevulinic acid dehydratase deficiency porphyria, acute lead intoxication and after oral 5-aminolevulinic acid loading."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >
      The concentration of total coproporphyrins was about 30-fold increased in
      patients with ALAD deficiency porphyria and acute lead intoxication as
      compared with controls.
    explanation: Patient biochemical data document elevated urinary coproporphyrins.
genetic:
- name: ALAD pathogenic variants
  gene_term:
    preferred_term: ALAD
    term:
      id: hgnc:395
      label: ALAD
  association: Causative
  inheritance:
  - name: Autosomal recessive
    description: >
      Most reported genetic ADP patients have compound heterozygous or
      homozygous ALAD variants with very low residual enzyme activity.
  features: >
    Pathogenic ALAD variants reduce porphobilinogen synthase activity through
    unstable, low-activity, or conformationally shifted proteins. The disorder
    is molecularly heterogeneous, and the 2026 update reported the first known
    female patient.
  evidence:
  - reference: PMID:16343966
    reference_title: "delta-Aminolevulinate dehydratase (ALAD) porphyria: the first case in North America with two novel ALAD mutations."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >
      This case represents the molecular analysis of the ALAD gene defects in
      the first case of ADP identified in North America, who is a compound
      heterozygote for two novel ALAD gene defects.
    explanation: This directly supports compound heterozygous ALAD variants as causative.
  - reference: PMID:41268747
    reference_title: "New cases of delta-aminolevulinic acid dehydratase deficiency: Functional insights into gene variants using an innovative mouse liver model."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >
      These findings underscore the molecular heterogeneity of the ALAD gene
      and present the first reported case of ADP in a female patient.
    explanation: Recent patient data broaden the molecular and sex representation of reported genetic ADP cases.
  - reference: CGGV:assertion_0ac683af-ca8d-46ab-8641-66ab9b537d16-2025-01-14T200000.000Z
    reference_title: "ALAD / porphyria due to ALA dehydratase deficiency (Moderate)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "ALAD | HGNC:395 | porphyria due to ALA dehydratase deficiency | MONDO:0013000 | AR | Moderate"
    explanation: ClinGen classifies the ALAD-porphyria due to ALA dehydratase deficiency gene-disease relationship as moderate with autosomal recessive inheritance.
diagnosis:
- name: Urinary ALA and porphobilinogen measurement
  diagnosis_term:
    preferred_term: urine chemistry measurement
    term:
      id: MAXO:0000789
      label: urine chemistry measurement
  description: >
    During symptoms, urine chemistry should measure ALA and PBG together. ADP is
    suggested by high ALA without the PBG overproduction typical of AIP.
  results: Increased urinary ALA with absent or non-increased urinary PBG supports ADP over AIP.
  evidence:
  - reference: PMID:9516683
    reference_title: "ALAD porphyria."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >
      The symptoms in this disease are similar to those seen in AIP, but ALAD
      porphyria can be differentiated from AIP by its autosomal recessive,
      rather than dominant, inheritance, by the lack of PBG overproduction, and
      by markedly decreased ALAD activity.
    explanation: This directly supports the diagnostic distinction using PBG and ALAD activity.
- name: Erythrocyte ALAD enzyme activity
  diagnosis_term:
    preferred_term: diagnostic procedure
    term:
      id: MAXO:0000003
      label: diagnostic procedure
  description: >
    Measurement of erythrocyte ALAD activity supports confirmation of ADP and
    helps distinguish inherited deficiency from other acute porphyrias.
  results: Markedly reduced erythrocyte ALAD activity supports ADP.
  evidence:
  - reference: PMID:9516683
    reference_title: "ALAD porphyria."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >
      The symptoms in this disease are similar to those seen in AIP, but ALAD
      porphyria can be differentiated from AIP by its autosomal recessive,
      rather than dominant, inheritance, by the lack of PBG overproduction, and
      by markedly decreased ALAD activity.
    explanation: This review identifies markedly decreased ALAD activity as a key diagnostic discriminator.
- name: ALAD molecular genetic testing
  diagnosis_term:
    preferred_term: genetic testing
    term:
      id: MAXO:0000127
      label: genetic testing
  description: >
    Molecular testing confirms biallelic ALAD pathogenic variants after
    biochemical testing suggests ADP.
  results: Biallelic pathogenic ALAD variants confirm genetic ADP.
  evidence:
  - reference: PMID:16343966
    reference_title: "delta-Aminolevulinate dehydratase (ALAD) porphyria: the first case in North America with two novel ALAD mutations."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >
      Nucleotide sequence analysis of ALAD cDNAs from the proband revealed two
      novel mutations, a 265G to A base transition (C1) and a 394C to T base
      transition (C2), resulting in amino acid substitutions, Glu89Lys and
      Cys132Arg, respectively.
    explanation: Patient sequencing established the molecular diagnosis.
treatments:
- name: Intravenous hemin or heme arginate for acute attacks
  description: >
    Intravenous hemin or heme arginate is the best documented attack-directed
    therapy in ADP. Clinical benefit supports hepatic ALAS1 repression and
    reduction of ALA production as the main therapeutic mechanism.
  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 excess ALA production
    treatment_effect: INHIBITS
    description: >
      Heme therapy represses hepatic ALAS1 and reduces the upstream ALA burden.
    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: >
        Elevation in circulating hepatic ALAS1 and response to treatment with
        hemin indicate that the liver is an important source of excess ALA in
        ADP, although the marrow may also contribute.
      explanation: ADP patient data link hemin response to hepatic ALAS1-associated ALA production.
  - target: Hepatic and erythroid ALA accumulation without PBG overproduction
    treatment_effect: INHIBITS
    description: >
      Heme arginate plus glucose lowers urinary ALA and total porphyrins in
      documented ADP crises.
    evidence:
    - reference: PMID:9732973
      reference_title: "5-Aminolevulinic acid dehydratase deficiency porphyria: a twenty-year clinical and biochemical follow-up."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >
        After this therapy both urinary 5-aminolevulinic acid (ALA) and total
        porphyrins were diminished to 65% in patient B.
      explanation: Longitudinal ADP treatment data show biochemical improvement after heme arginate and glucose.
  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: >
      Intravenous hemin was effective in most reported cases for treatment and
      prevention of acute attacks of neurological symptoms.
    explanation: Review of documented ADP cases supports intravenous hemin for attack treatment and prevention.
  - reference: PMID:35991568
    reference_title: "Case Report: Lack of Response to Givosiran in a Case of ALAD Porphyria."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >
      Hemin infusions are often effective in treating and preventing such
      attacks.
    explanation: The 2022 ADP case report summarizes hemin as an often-effective attack therapy.
- name: Glucose infusion or carbohydrate loading
  description: >
    Glucose infusion has been used with heme arginate during acute ADP crises,
    but available evidence supports it as adjunctive rather than definitive
    therapy.
  treatment_term:
    preferred_term: dietary intervention
    term:
      id: MAXO:0000088
      label: dietary intervention
    therapeutic_agent:
    - preferred_term: glucose
      term:
        id: CHEBI:17234
        label: glucose
  evidence:
  - reference: PMID:9732973
    reference_title: "5-Aminolevulinic acid dehydratase deficiency porphyria: a twenty-year clinical and biochemical follow-up."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >
      An acute crisis in each patient was successfully treated by infusion of
      glucose and heme arginate.
    explanation: Long-term ADP follow-up documents glucose used with heme arginate in successful crisis treatment.
- name: Givosiran not established for ADP
  description: >
    Givosiran is approved for recurrent acute hepatic porphyria attacks, but the
    published ADP experience in one patient reported continued attacks and only
    transient ALA decreases related to rescue hemin. The treatment remains
    uncertain for ADP specifically.
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: givosiran
      term:
        id: NCIT:C146805
        label: Givosiran
  evidence:
  - reference: PMID:35991568
    reference_title: "Case Report: Lack of Response to Givosiran in a Case of ALAD Porphyria."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >
      The patient has continued to have recurrent attacks, with transient
      decreases in ALA levels only as related to treatment of his attacks with
      hemin.
    explanation: This patient-level report cautions against assuming givosiran efficacy in ADP.
- name: Hydroxyurea as experimental erythroid-directed option
  description: >
    Hydroxyurea has only case-level rationale in ADP. It may be considered
    investigational when an erythropoietic contribution is suspected, but there
    is no controlled evidence base.
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: hydroxyurea
      term:
        id: CHEBI:44423
        label: hydroxyurea
  evidence:
  - reference: PMID:35991568
    reference_title: "Case Report: Lack of Response to Givosiran in a Case of ALAD Porphyria."
    supports: PARTIAL
    evidence_source: HUMAN_CLINICAL
    snippet: >
      Since ADP may have an erythropoietic component, treatment with
      hydroxyurea, which was beneficial in one previous case, is planned.
    explanation: This supports hydroxyurea only as a limited case-level/experimental option, not established therapy.
clinical_trials:
- name: NCT03338816
  phase: PHASE_III
  status: COMPLETED
  description: >
    ENVISION was the pivotal phase III study of givosiran in acute hepatic
    porphyrias. It is relevant background for givosiran exposure in the AHP
    class, but published ADP-specific case evidence does not establish efficacy.
  evidence:
  - reference: clinicaltrials:NCT03338816
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >
      The purpose of this study is to evaluate the effect of subcutaneous
      givosiran (ALN-AS1), compared to placebo, on the rate of porphyria
      attacks in patients with Acute Hepatic Porphyrias (AHP).
    explanation: ClinicalTrials.gov documents the general AHP givosiran trial that motivated ADP use, while the treatment entry separately captures ADP-specific uncertainty.
differential_diagnoses:
- name: Acute intermittent porphyria
  description: >
    AIP causes similar neurovisceral attacks but is autosomal dominant and
    characterized by PBG overproduction, while ALAD porphyria is autosomal
    recessive with markedly decreased ALAD activity and little or no PBG
    overproduction.
  disease_term:
    preferred_term: acute intermittent porphyria
    term:
      id: MONDO:0008294
      label: acute intermittent porphyria
  evidence:
  - reference: PMID:9516683
    reference_title: "ALAD porphyria."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >
      The symptoms in this disease are similar to those seen in AIP, but ALAD
      porphyria can be differentiated from AIP by its autosomal recessive,
      rather than dominant, inheritance, by the lack of PBG overproduction, and
      by markedly decreased ALAD activity.
    explanation: This directly supports AIP as the key clinical and biochemical differential.
- name: Acquired ALAD inhibition from lead intoxication
  description: >
    Lead intoxication can inhibit ALAD and mimic aspects of ADP biochemistry,
    including increased ALA and coproporphyrins. Exposure history and genetic
    testing help distinguish acquired inhibition from inherited ADP.
  disease_term:
    preferred_term: lead poisoning
    term:
      id: MONDO:0018019
      label: lead poisoning
  evidence:
  - reference: PMID:10211628
    reference_title: "Investigations on the formation of urinary coproporphyrin isomers I-IV in 5-aminolevulinic acid dehydratase deficiency porphyria, acute lead intoxication and after oral 5-aminolevulinic acid loading."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >
      These results demonstrate that oral ALA loading can be used as an in vivo
      model to study the metabolism of the four urinary coproporphyrin isomers
      I-IV especially in ALAD deficiency porphyria and in acute lead poisoning.
    explanation: This supports lead intoxication as a biochemical mimic and comparator for ALAD inhibition.
- name: Tyrosinemia type I
  description: >
    Tyrosinemia type I can mimic acute porphyria biochemically and clinically
    because succinylacetone, an abnormal tyrosine-catabolism metabolite,
    inhibits ALAD and causes excessive urinary ALA without inherited ALAD
    variants.
  disease_term:
    preferred_term: tyrosinemia type I
    term:
      id: MONDO:0010161
      label: tyrosinemia type I
  evidence:
  - reference: PMID:6826727
    reference_title: "Hereditary tyrosinemia and the heme biosynthetic pathway. Profound inhibition of delta-aminolevulinic acid dehydratase activity by succinylacetone."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >
      It is known that patients with this hereditary disease excrete excessive
      amounts of delta-aminolevulinic acid (ALA) in urine and that certain
      patients have an accompanying clinical syndrome resembling that of acute
      intermittent porphyria (AIP).
    explanation: Patient observations support tyrosinemia type I as an acute-porphyria mimic.
  - reference: PMID:6826727
    reference_title: "Hereditary tyrosinemia and the heme biosynthetic pathway. Profound inhibition of delta-aminolevulinic acid dehydratase activity by succinylacetone."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >
      Our data indicate that succinylacetone is an extremely potent competitive
      inhibitor of ALA dehydratase in human as well as in animal tissues.
    explanation: Biochemical enzyme data support succinylacetone-mediated ALAD inhibition as the mimic mechanism.
📚

References & Deep Research

References

13
Porphyria due to ALA dehydratase deficiency
1 finding
Orphanet defines ALAD porphyria as an acute hepatic porphyria without skin symptoms.
"A rare acute hepatic porphyria characterized by neurovisceral attacks without skin symptoms."
Show evidence (1 reference)
ORPHA:100924 SUPPORT Other
"A rare acute hepatic porphyria characterized by neurovisceral attacks without skin symptoms."
Orphanet provides the core disease definition.
ALAD porphyria.
1 finding
ALAD porphyria differs biochemically from AIP because ALA, but not PBG, is overproduced.
"Because of an almost complete lack of ALAD activity, patients excrete a large amount of ALA, but not PBG, into urine. "
Show evidence (1 reference)
PMID:9516683 SUPPORT Human Clinical
"Because of an almost complete lack of ALAD activity, patients excrete a large amount of ALA, but not PBG, into urine. "
This review summarizes the distinguishing diagnostic biochemical pattern of ADP.
5-Aminolevulinate dehydratase porphyria: Update on hepatic 5-aminolevulinic acid synthase induction and long-term response to hemin.
1 finding
Hepatic ALAS1 induction and hemin response support a hepatic source of excess ALA in ADP.
"Elevation in circulating hepatic ALAS1 and response to treatment with hemin indicate that the liver is an important source of excess ALA in ADP, although the marrow may also contribute. "
Show evidence (1 reference)
PMID:33199206 SUPPORT Human Clinical
"Elevation in circulating hepatic ALAS1 and response to treatment with hemin indicate that the liver is an important source of excess ALA in ADP, although the marrow may also contribute. "
This patient update links hepatic ALAS1 induction, excess ALA production, and hemin responsiveness.
Porphyric neuropathy.
1 finding
Acute hepatic porphyria neuropathy can progress to quadriparesis and respiratory weakness.
"Acute hepatic porphyrias are inherited metabolic disorders that may present with polyneuropathy, which if not diagnosed early can lead to quadriparesis, respiratory weakness, and death. "
Show evidence (1 reference)
PMID:33786855 SUPPORT Human Clinical
"Acute hepatic porphyrias are inherited metabolic disorders that may present with polyneuropathy, which if not diagnosed early can lead to quadriparesis, respiratory weakness, and death. "
ADP is an acute hepatic porphyria, so this review supports neuropathic weakness and respiratory weakness as severe downstream attack manifestations.
Hereditary tyrosinemia and the heme biosynthetic pathway. Profound inhibition of delta-aminolevulinic acid dehydratase activity by succinylacetone.
1 finding
Hereditary tyrosinemia type I can mimic acute porphyria through succinylacetone-mediated ALAD inhibition.
"Patients with hereditary tyrosinemia can excrete excessive urinary ALA and develop a syndrome resembling acute intermittent porphyria, while succinylacetone competitively inhibits ALA dehydratase. "
Show evidence (2 references)
PMID:6826727 SUPPORT Human Clinical
"It is known that patients with this hereditary disease excrete excessive amounts of delta-aminolevulinic acid (ALA) in urine and that certain patients have an accompanying clinical syndrome resembling that of acute intermittent porphyria (AIP). "
Patient observations support tyrosinemia type I as an acute-porphyria mimic.
+ 1 more reference
Porphyria Diagnostics-Part 1: A Brief Overview of the Porphyrias
No top-level findings curated for this source.
The third case of Doss porphyria (delta-aminolevulinic acid dehydratase deficiency) in Germany
No top-level findings curated for this source.
AGA Clinical Practice Update on Diagnosis and Management of Acute Hepatic Porphyrias: Expert Review
No top-level findings curated for this source.
The Hepatic Porphyrias: Revealing the Complexities of a Rare Disease
No top-level findings curated for this source.
5-Aminolevulinic acid dehydratase deficiency porphyria: a twenty-year clinical and biochemical follow-up
No top-level findings curated for this source.
Functional characterization of new pathogenic and lead-poisoning predisposing variants in ALA Dehydratase Porphyria
No top-level findings curated for this source.
Case Report: Lack of Response to Givosiran in a Case of ALAD Porphyria
No top-level findings curated for this source.
Laboratory Diagnosis of Porphyria
No top-level findings curated for this source.

Deep Research

1
Falcon
Disease Characteristics Research Template
Edison Scientific Literature 26 citations 2026-05-05T02:50:19.701143

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: Porphyria due to ALA Dehydratase Deficiency
  • MONDO ID: (if available)
  • Category: Mendelian

Research Objectives

Please provide a comprehensive research report on Porphyria due to ALA Dehydratase Deficiency 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

Comprehensive research report: Porphyria due to ALA Dehydratase Deficiency (ALAD deficiency porphyria; ADP; Doss porphyria)

Executive summary

Porphyria due to ALA dehydratase deficiency (ADP) is an ultra-rare, autosomal recessive acute hepatic porphyria caused by biallelic pathogenic variants in ALAD (also called porphobilinogen synthase, PBGS), leading to profound deficiency of ALA dehydratase—the second enzyme in heme biosynthesis. The most characteristic biochemical pattern is markedly elevated δ-aminolevulinic acid (ALA) with porphobilinogen (PBG) normal or only slightly elevated, plus increased urinary coproporphyrins and erythrocyte zinc protoporphyrin. Clinically it presents with acute neurovisceral attacks (severe abdominal pain, autonomic symptoms, and peripheral neuropathy/weakness) without typical cutaneous features. Evidence-based 2023 expert guidance for acute hepatic porphyrias highlights that PBG is elevated in all acute hepatic porphyrias except ALAD porphyria, which has important diagnostic implications. First-line management is shared with other acute hepatic porphyrias (trigger avoidance, carbohydrate loading, and IV hemin), but emerging therapies (e.g., givosiran) may be less effective in ADP based on limited case-level evidence. (wang2023agaclinicalpractice pages 1-3, wang2023agaclinicalpractice pages 3-5, graff2022casereportlack pages 1-2)


1. Disease information

1.1 What is the disease?

ADP is an inborn error of heme biosynthesis classified among acute hepatic porphyrias (AHPs). It results from a severe deficiency of 5-aminolevulinic acid dehydratase (ALAD), causing accumulation of upstream heme precursors—especially ALA—and episodic, potentially severe neurovisceral attacks. (ramanujam2015porphyriadiagnostics—part1 pages 9-11, wang2023agaclinicalpractice pages 1-3)

1.2 Key identifiers (available from retrieved evidence)

  • OMIM: 612740 (explicitly reported in peer-reviewed sources). (graff2022casereportlack pages 1-2, ramanujam2015porphyriadiagnostics—part1 pages 9-11)
  • MONDO / Orphanet / ICD-10/ICD-11 / MeSH: not directly retrievable from the captured evidence set in this run; therefore not reported here to avoid uncited/incorrect identifiers.

1.3 Common synonyms / alternative names

  • ALAD deficiency porphyria (ADP)
  • ALAD porphyria
  • ALA dehydratase deficiency porphyria
  • Doss porphyria (ramanujam2015porphyriadiagnostics—part1 pages 9-11)

1.4 Evidence source type

Most ADP knowledge is derived from: - Aggregated disease-level expert reviews and guidelines (e.g., AGA Clinical Practice Update for AHPs). (wang2023agaclinicalpractice pages 1-3) - A very small number of individual human cases/longitudinal follow-up studies due to extreme rarity. (gross19985aminolevulinicaciddehydratase pages 1-2, doss2004thethirdcase pages 1-4)


2. Etiology

2.1 Primary causal factors

  • Genetic cause: biallelic pathogenic variants in ALAD leading to profound enzyme deficiency. ADP is described as autosomal recessive, with affected individuals typically compound heterozygotes; heterozygous carriers (~50% activity) are usually asymptomatic. (ramanujam2015porphyriadiagnostics—part1 pages 9-11, gross19985aminolevulinicaciddehydratase pages 1-2)
  • Mechanistic cause: deficiency of ALAD blocks conversion of 2 ALA → PBG, leading to ALA accumulation and downstream porphyrin abnormalities. (balogun2023thehepaticporphyrias pages 3-5, graff2022casereportlack pages 1-2)

2.2 Risk factors / triggers

Evidence across ADP-focused reviews/cases indicates that ALAD activity can be reduced by genetic deficiency or secondary inhibition, creating an ADP-like biochemical/clinical picture: - Lead exposure: ALAD is zinc-dependent and susceptible to inactivation when lead replaces Zn2+. (balogun2023thehepaticporphyrias pages 3-5, ramanujam2015porphyriadiagnostics—part1 pages 9-11) - Hereditary tyrosinemia type 1: via succinylacetone-mediated ALAD inhibition (noted as a differential/secondary cause in ADP-focused review). (ramanujam2015porphyriadiagnostics—part1 pages 9-11) - Alcohol ingestion: associated with at least one severe attack in long-term follow-up; alcohol can increase hepatic ALAS activity and precipitate crises. (gross19985aminolevulinicaciddehydratase pages 4-5, gross19985aminolevulinicaciddehydratase pages 2-3) - Other conditions listed as potential contributors to reduced ALAD activity / ADP-like biochemical patterns include zinc deficiency, smoking, diabetes, and chronic renal failure. (ramanujam2015porphyriadiagnostics—part1 pages 9-11)

2.3 Protective factors

No ADP-specific protective genetic variants or environmental protective factors were identified in the captured evidence set.

2.4 Gene–environment interaction

A practical, clinically relevant interaction is carrier status + lead exposure: heterozygotes with partial ALAD activity are generally asymptomatic but may have increased susceptibility to lead toxicity. (ramanujam2015porphyriadiagnostics—part1 pages 9-11)


3. Phenotypes

3.1 Core phenotype types and characteristics

Symptoms/signs (neurovisceral attacks): - Severe abdominal pain (often colicky) during acute crises. (doss2004thethirdcase pages 1-4) - Peripheral neuropathy / weakness, including polyneuropathy and potentially persistent deficits (e.g., paresis; “foot and wrist drop” reported in a chronic course). (graff2022casereportlack pages 1-2, gross19985aminolevulinicaciddehydratase pages 1-2) - Autonomic/cardiovascular involvement reported in long-term follow-up (“cardiovascular symptoms”). (gross19985aminolevulinicaciddehydratase pages 1-2) - Severe crises can include transient respiratory paralysis / respiratory involvement. (gross19985aminolevulinicaciddehydratase pages 1-2)

Onset / course: - Typically childhood to adolescence in reported cases; one longitudinal case began at age 12 and continued into adulthood with recurrent attacks. (graff2022casereportlack pages 1-2, gross19985aminolevulinicaciddehydratase pages 1-2) - The disorder is so rare that phenotype frequency estimates are not robust; older reviews emphasized extremely small case counts (≈6–8 cases worldwide). (ramanujam2015porphyriadiagnostics—part1 pages 9-11, graff2022casereportlack pages 1-2)

Cutaneous findings: - ADP is described as presenting with neurovisceral symptoms similar to other acute porphyrias without cutaneous manifestations in classic descriptions. (ramanujam2015porphyriadiagnostics—part1 pages 9-11)

3.2 Suggested HPO terms (non-exhaustive; based on reported features)

  • Abdominal pain HP:0002027
  • Peripheral neuropathy HP:0009830
  • Muscle weakness HP:0001324
  • Paresis HP:0003470
  • Respiratory insufficiency / failure HP:0002878 / HP:0002877

3.3 Quality of life impact

Direct ADP-specific QoL instruments were not captured in the evidence set; however, the described recurrent attacks and persistent neuropathic deficits imply major functional impairment in some individuals (case-level evidence). (graff2022casereportlack pages 1-2)


4. Genetic / molecular information

4.1 Causal gene

  • ALAD (porphobilinogen synthase; PBGS), located at chromosome 9q34 in classic reviews, encoding a zinc-dependent enzyme catalyzing the condensation of two ALA molecules to form PBG. (ramanujam2015porphyriadiagnostics—part1 pages 9-11, balogun2023thehepaticporphyrias pages 3-5)

4.2 Example pathogenic variants (illustrative; not comprehensive)

From an ADP case report (2022): - c.265G>A (p.Glu89Lys) and c.394T>C (p.Cys132Arg) in ALAD. (graff2022casereportlack pages 1-2)

From a 2004 genetically characterized case: - Compound heterozygous intronic substitutions in intron 3 (IVS3 -11C substitutions), proposed to alter splicing. (doss2004thethirdcase pages 1-4)

From 2024 functional characterization (conference poster): - Newly reported variants in three young patients including c.440_441delinsTT (reported to yield p.Arg147Leu) (homozygous in siblings) and compound heterozygosity for c.839G>A (p.Gly280Glu) and c.724G>A (p.Val242Ile); in vivo hepatocyte expression in C57BL/6 mice showed ~5% wild-type activity for one variant. (castelbon202404163functionalcharacterization pages 1-1)

Protein dysfunction concepts: - A 2023 hepatic porphyria review describes ADP as a “conformational disease,” with mutations causing destabilized tertiary/quaternary structure, misfolding, and reduced half-life; it also reiterates lead’s displacement of Zn2+ leading to inactivation. (balogun2023thehepaticporphyrias pages 3-5)

4.3 Variant classes

Across reports: missense, small indels, and intronic/splice-affecting variants are represented. (graff2022casereportlack pages 1-2, doss2004thethirdcase pages 1-4, castelbon202404163functionalcharacterization pages 1-1)

4.4 Modifier genes / epigenetics

No ADP-specific modifier genes or epigenetic changes were identified in the captured evidence set.


5. Environmental information

5.1 Environmental contributors

  • Lead is the key environmental factor: it inhibits ALAD by replacing zinc and can mimic ADP. (balogun2023thehepaticporphyrias pages 3-5, ramanujam2015porphyriadiagnostics—part1 pages 9-11)

5.2 Lifestyle contributors

  • Alcohol may precipitate attacks (case-level evidence). (gross19985aminolevulinicaciddehydratase pages 4-5, gross19985aminolevulinicaciddehydratase pages 2-3)

5.3 Infectious agents

No infectious etiology is implicated.


6. Mechanism / pathophysiology

6.1 Molecular pathway (heme biosynthesis)

ALAD is the second enzyme in heme biosynthesis and catalyzes the condensation of two ALA molecules to form PBG. Deficiency leads to ALA accumulation and characteristic downstream porphyrin abnormalities. (balogun2023thehepaticporphyrias pages 3-5, graff2022casereportlack pages 1-2)

6.2 Causal chain (conceptual)

1) Biallelic ALAD pathogenic variants → profound enzyme deficiency in relevant tissues (erythrocytes; and likely hepatic/erythroid contributions). (graff2022casereportlack pages 1-2, ramanujam2015porphyriadiagnostics—part1 pages 9-11) 2) Block in ALA→PBG step → marked ALA accumulation (urine/plasma). (doss2004thethirdcase pages 1-4, gross19985aminolevulinicaciddehydratase pages 2-3) 3) Accumulated ALA and altered porphyrin intermediates associate with acute neurovisceral attacks and neuropathy. (gross19985aminolevulinicaciddehydratase pages 1-2, graff2022casereportlack pages 1-2)

6.3 Biochemical abnormalities (with data)

  • Urinary ALA: reported 32-fold elevation in a 17-year-old case; in 20-year follow-up, 44–80 fold elevations were documented at various times. (doss2004thethirdcase pages 1-4, gross19985aminolevulinicaciddehydratase pages 2-3)
  • Urinary PBG: normal or slightly elevated in ADP (key differentiator), though some long-term data show PBG elevations during crises; expert guidance emphasizes that PBG is not reliably elevated in ALAD porphyria. (graff2022casereportlack pages 1-2, wang2023agaclinicalpractice pages 3-5, gross19985aminolevulinicaciddehydratase pages 2-3)
  • Urinary coproporphyrins: e.g., 76-fold increased coproporphyrin in one case; excessive urinary coproporphyrin excretion in long-term follow-up. (doss2004thethirdcase pages 1-4, gross19985aminolevulinicaciddehydratase pages 4-5)
  • Erythrocyte zinc protoporphyrin: e.g., 5.4-fold elevated in one case; noted as increased in case report. (doss2004thethirdcase pages 1-4, graff2022casereportlack pages 1-2)
  • ALAD enzyme activity: often <10% of normal, sustained over decades in follow-up; a 2004 case had 10% activity. (gross19985aminolevulinicaciddehydratase pages 1-2, doss2004thethirdcase pages 1-4)

6.4 Ontology suggestions (for knowledge base population)

  • GO (Biological Process): heme biosynthetic process; porphyrin-containing compound metabolic process.
  • GO (Molecular Function): delta-aminolevulinic acid dehydratase activity.
  • UBERON (anatomy): liver; bone marrow; peripheral nerve.
  • CL (cell types): hepatocyte; erythroblast/erythroid lineage.

6.5 Molecular profiling / multi-omics

No ADP-specific transcriptomic/proteomic/metabolomic multi-omics datasets were identified in the captured evidence set. A 2024 poster used an in vivo hepatocyte expression assay for functional evaluation of variants. (castelbon202404163functionalcharacterization pages 1-1)


7. Anatomical structures affected

Based on neurovisceral attacks and biochemical production/handling of heme intermediates: - Liver (UBERON:0002107): central to AHP biochemistry and therapeutic targeting (e.g., ALAS1 suppression strategies). (wang2023agaclinicalpractice pages 1-3, NCT03338816 chunk 1) - Peripheral nervous system / peripheral nerves: neuropathy/weakness and motor deficits are prominent. (graff2022casereportlack pages 1-2, gross19985aminolevulinicaciddehydratase pages 1-2) - Blood/erythroid compartment: erythrocyte ALAD deficiency and zinc protoporphyrin elevation are diagnostic clues. (gross19985aminolevulinicaciddehydratase pages 1-2, graff2022casereportlack pages 1-2)


8. Temporal development

8.1 Onset

  • Commonly childhood/adolescence in reported cases. (graff2022casereportlack pages 1-2, gross19985aminolevulinicaciddehydratase pages 1-2)

8.2 Course

  • Can be episodic with acute attacks; some cases show chronic neurologic sequelae after repeated attacks. (graff2022casereportlack pages 1-2, gross19985aminolevulinicaciddehydratase pages 1-2)

9. Inheritance and population

9.1 Inheritance

  • Autosomal recessive. (ramanujam2015porphyriadiagnostics—part1 pages 9-11, gross19985aminolevulinicaciddehydratase pages 1-2)

9.2 Epidemiology (best available in retrieved evidence)

  • Extremely rare: described as only ~6 documented cases in an older authoritative diagnostic review and ~8 documented cases worldwide in a 2022 case report. (ramanujam2015porphyriadiagnostics—part1 pages 9-11, graff2022casereportlack pages 1-2)
  • The 2023 AGA expert review notes fewer than a dozen reported cases. (wang2023agaclinicalpractice pages 1-3)

9.3 Population genetics (carrier frequency / variant distribution)

Not available from the captured evidence set (e.g., gnomAD/ClinVar frequencies were not retrieved in this run).


10. Diagnostics

10.1 Clinical suspicion

Patients can present with recurrent severe abdominal pain and neurologic/autonomic symptoms consistent with acute hepatic porphyria. Because symptoms are nonspecific, expert guidance recommends screening during an attack. (wang2023agaclinicalpractice pages 1-3)

10.2 First-line biochemical testing (expert guidance, 2023)

The AGA Clinical Practice Update recommends random urine ALA and PBG corrected to creatinine as screening tests in suspected AHP; importantly, it highlights that PBG is elevated in all AHP except ALAD porphyria, so an ADP pattern may be high ALA with absent/minimal PBG elevation. (wang2023agaclinicalpractice pages 1-3, wang2023agaclinicalpractice pages 3-5)

10.3 Second-line / confirmatory testing

  • Porphyrin fractionation in urine/plasma/feces and erythrocyte porphyrin profiling (e.g., Zn-protoporphyrin) can support subtype differentiation. (pierro2021laboratorydiagnosisof pages 12-13)
  • Erythrocyte ALAD enzyme activity assay: diagnostically useful but pre-analytically sensitive—ALAD activity deteriorates rapidly; testing should be performed within ~24h of blood draw. (pierro2021laboratorydiagnosisof pages 12-13)
  • Genetic confirmation: sequencing of ALAD is used to confirm subtype after biochemical evidence. (wang2023agaclinicalpractice pages 1-3)

10.4 Plasma fluorescence scanning

A diagnostics review describes plasma fluorescence scanning as a rapid qualitative screen; ADP/AIP/HCP may show emission maxima around 618–622 nm in symptomatic patients, supporting porphyria-type discrimination. (pierro2021laboratorydiagnosisof pages 2-4)

10.5 Differential diagnosis (high priority)

  • Lead poisoning (acquired ALAD inhibition) is a major mimic and should be excluded with blood lead testing and exposure history. (ramanujam2015porphyriadiagnostics—part1 pages 9-11, balogun2023thehepaticporphyrias pages 3-5)
  • Hereditary tyrosinemia type 1 (succinylacetone ALAD inhibition). (ramanujam2015porphyriadiagnostics—part1 pages 9-11)

11. Outcomes / prognosis

11.1 Morbidity

  • Long-term follow-up documents potentially severe morbidity, including persistent paresis and transient respiratory paralysis during crises. (gross19985aminolevulinicaciddehydratase pages 1-2)
  • A 2022 ADP case illustrates chronic sequelae (permanent motor deficits) and complications of long-term therapy (iron overload), plus compensated cirrhosis. (graff2022casereportlack pages 2-4)

11.2 Survival

  • Long-term outcomes vary: two long-followed patients were reported alive and in good health at age ~40 (historic cohort). (gross19985aminolevulinicaciddehydratase pages 4-5)
  • One child reportedly died after liver transplantation, and another older adult died within two years of onset in historical summaries. (gross19985aminolevulinicaciddehydratase pages 4-5)

Because of extreme rarity and case ascertainment bias, formal survival rates are not available.


12. Treatment

12.1 Acute attack management and disease-modifying therapy (expert guidance)

The 2023 AGA Clinical Practice Update for AHPs lists cornerstones of management: discontinuation of porphyrinogenic drugs/chemicals, oral/IV dextrose, IV hemin, and symptomatic therapy; for frequent attacks (≥4/year), prophylaxis with IV hemin or subcutaneous givosiran is considered, and liver transplantation is a curative option in refractory cases (general AHP guidance). (wang2023agaclinicalpractice pages 1-3)

12.2 Hemin / heme arginate (best-supported for ADP)

Human case data support efficacy: - A 20-year follow-up reported acute crises “successfully treated” with glucose plus heme arginate, with reductions in urinary ALA and porphyrins and sustained symptom-free periods. (gross19985aminolevulinicaciddehydratase pages 1-2) - A 2004 case (17-year-old) improved with haem arginate; weekly haem for one year provided sustained biochemical/clinical benefit and appeared prophylactic. (doss2004thethirdcase pages 1-4)

Adverse effects / implementation issues: - Long-term prophylactic hemin can cause iron overload; in a 2022 case, ferritin reached 659 ng/mL and was managed with phlebotomy. (graff2022casereportlack pages 1-2)

MAXO suggestions: intravenous hemin administration; heme arginate therapy; intravenous glucose administration.

12.3 Givosiran (RNAi targeting hepatic ALAS1)

Clinical trial landscape: - The phase 3 ENVISION trial (NCT03338816) lists ALA dehydratase deficient porphyria among included conditions and measures urinary ALA/PBG and attack rates; however, the excerpted record does not provide numeric results in this evidence set. (NCT03338816 chunk 1)

ADP-specific real-world evidence: - A 2022 ADP case report describes a patient treated with givosiran (2.5 mg/kg monthly) for 6 months with no observed liver adverse effects, but continued recurrent attacks and only transient ALA decreases associated with hemin infusions; the authors conclude givosiran “may not be effective” for ADP based on this single case. (graff2022casereportlack pages 1-2, graff2022casereportlack pages 2-4)

Figure-based evidence: The paper’s Figure 1 shows urine ALA decreases after hemin but lack of sustained suppression with givosiran and persistent elevation of related markers during the treatment interval. (graff2022casereportlack media 69c1e72f, graff2022casereportlack media 97eb2153, graff2022casereportlack media 0a38561c)

MAXO suggestions: small interfering RNA therapy; ALAS1 inhibition therapy (mechanism-based).

12.4 Hydroxyurea (experimental/repurposed)

A 2022 case report notes hydroxyurea was “beneficial in one previous case” and was planned for the reported patient due to a possible erythropoietic component of ADP, but controlled evidence is lacking. (graff2022casereportlack pages 1-2)

MAXO suggestion: hydroxyurea therapy.

12.5 Liver transplantation

Historical evidence suggests limited benefit in at least one child with ADP, and expert reviews reserve transplantation for refractory AHP generally. (ramanujam2015porphyriadiagnostics—part1 pages 9-11, wang2023agaclinicalpractice pages 1-3, gross19985aminolevulinicaciddehydratase pages 4-5)

MAXO suggestion: liver transplantation.


13. Prevention

13.1 Primary prevention

  • Avoid or minimize exposure to porphyrinogenic drugs/chemicals (general AHP prevention principle). (wang2023agaclinicalpractice pages 1-3)
  • Prevent lead exposure, given its direct ALAD inhibition and potential to mimic/precipitate ADP-like crises. (balogun2023thehepaticporphyrias pages 3-5, ramanujam2015porphyriadiagnostics—part1 pages 9-11)

13.2 Secondary prevention

  • Early biochemical testing during attacks (urine ALA/PBG) to prevent misdiagnosis and delayed hemin therapy. (wang2023agaclinicalpractice pages 1-3)

13.3 Tertiary prevention

  • For recurrent attacks, consider prophylaxis (e.g., hemin protocols) and monitor treatment complications (iron overload). (graff2022casereportlack pages 1-2)

13.4 Genetic counseling

After biochemical diagnosis, confirm by ALAD sequencing and offer cascade testing to relatives for counseling (general AHP approach). (wang2023agaclinicalpractice pages 1-3)


14. Other species / natural disease

No naturally occurring ADP in other species was identified in the captured evidence set.


15. Model organisms

A 2024 conference poster reports in vivo functional characterization of newly identified ALAD variants by vector transfer into hepatocytes of C57BL/6 mice using hydrodynamic tail vein injection, with one variant showing ~5% wild-type enzyme activity. This supports use of mouse liver expression systems for variant functional validation in ADP. (castelbon202404163functionalcharacterization pages 1-1)


Recent developments and latest research (prioritizing 2023–2024)

1) 2023 expert clinical guidance (AGA Clinical Practice Update) clarified a key diagnostic pitfall: urinary PBG is elevated in all AHP except ALAD porphyria, reinforcing the need to measure ALA and PBG together and not rely on PBG alone. Publication date: March 2023. URL: https://doi.org/10.1053/j.gastro.2022.11.034 (wang2023agaclinicalpractice pages 3-5, wang2023agaclinicalpractice pages 1-3)

2) 2023 mechanistic synthesis emphasized ALAD’s Zn2+ dependence and lead susceptibility and framed ADP as a mutation-driven “conformational disease,” connecting structural disruption to enzyme instability/misfolding. Publication date: November 2023. URL: https://doi.org/10.1055/s-0043-1776760 (balogun2023thehepaticporphyrias pages 3-5)

3) 2024 variant discovery + functional validation (conference poster) reported previously unreported ALAD variants in young patients and used a mouse hepatocyte expression approach for functional assessment, illustrating continued discovery of allelic heterogeneity and translation of variant interpretation methods. Publication date: September 2024. URL: https://doi.org/10.1136/bmjgast-2024-icpp.75 (castelbon202404163functionalcharacterization pages 1-1)


Key statistics and data (from recent/primary studies)

  • Rarity: “only eight cases documented worldwide” (case report, Aug 2022). (graff2022casereportlack pages 1-2)
  • ALA elevations: urinary ALA 32-fold in one genetically confirmed case; 44–80 fold in long-term follow-up patients at various times. (doss2004thethirdcase pages 1-4, gross19985aminolevulinicaciddehydratase pages 2-3)
  • Enzyme deficiency: erythrocyte ALAD activity often <10% of normal over decades in follow-up. (gross19985aminolevulinicaciddehydratase pages 1-2)
  • Urinary coproporphyrin: 76-fold elevation reported in one acute case. (doss2004thethirdcase pages 1-4)

Structured summary table

Finding Details Key source (year; DOI/URL)
Disease name / identifiers 5-Aminolevulinic acid dehydratase deficiency porphyria; ALAD deficiency porphyria; ADP; Doss porphyria. OMIM 612740 reported in recent reviews/case reports. Described as the rarest/ultra-rare acute hepatic porphyria (graff2022casereportlack pages 1-2, ramanujam2015porphyriadiagnostics—part1 pages 9-11). Graff et al., 2022, Front Genet, https://doi.org/10.3389/fgene.2022.867856 (graff2022casereportlack pages 1-2); Ramanujam & Anderson, 2015, https://doi.org/10.1002/0471142905.hg1720s86 (ramanujam2015porphyriadiagnostics—part1 pages 9-11)
Synonyms ALAD porphyria, ALA dehydratase deficiency porphyria, aminolevulinate dehydratase deficiency porphyria, Doss porphyria (ramanujam2015porphyriadiagnostics—part1 pages 9-11). Ramanujam & Anderson, 2015, https://doi.org/10.1002/0471142905.hg1720s86 (ramanujam2015porphyriadiagnostics—part1 pages 9-11)
Inheritance Autosomal recessive; affected patients usually have biallelic/compound heterozygous ALAD variants; heterozygotes have ~50% ALAD activity and are usually asymptomatic (ramanujam2015porphyriadiagnostics—part1 pages 9-11, gross19985aminolevulinicaciddehydratase pages 1-2). Ramanujam & Anderson, 2015, https://doi.org/10.1002/0471142905.hg1720s86 (ramanujam2015porphyriadiagnostics—part1 pages 9-11); Gross et al., 1998, https://doi.org/10.1093/clinchem/44.9.1892 (gross19985aminolevulinicaciddehydratase pages 1-2)
Causal gene ALAD (also PBGS), chromosome 9q34; zinc-dependent enzyme catalyzing condensation of 2 ALA molecules to porphobilinogen (PBG) (ramanujam2015porphyriadiagnostics—part1 pages 9-11, balogun2023thehepaticporphyrias pages 3-5). Ramanujam & Anderson, 2015, https://doi.org/10.1002/0471142905.hg1720s86 (ramanujam2015porphyriadiagnostics—part1 pages 9-11); Balogun & Nejak-Bowen, 2023, https://doi.org/10.1055/s-0043-1776760 (balogun2023thehepaticporphyrias pages 3-5)
Example pathogenic variants Reported ALAD variants include c.265G>A p.Glu89Lys and c.394T>C p.Cys132Arg; historical/functional examples include K59N, F12L, G133R, R240W, A274T, V275M, delTC; 2024 poster reported c.440_441delinsTT / p.Arg147Leu, c.839G>A / p.Gly280Glu, and c.724G>A / p.Val242Ile (graff2022casereportlack pages 1-2, balogun2023thehepaticporphyrias pages 3-5, castelbon202404163functionalcharacterization pages 1-1). Graff et al., 2022, https://doi.org/10.3389/fgene.2022.867856 (graff2022casereportlack pages 1-2); Balogun & Nejak-Bowen, 2023, https://doi.org/10.1055/s-0043-1776760 (balogun2023thehepaticporphyrias pages 3-5); Castelbón et al., 2024 poster, https://doi.org/10.1136/bmjgast-2024-icpp.75 (castelbon202404163functionalcharacterization pages 1-1)
Key biochemical finding: ALA Markedly increased urinary/plasma ALA is the hallmark; examples include 32-fold urinary increase in one 17-year-old case, and 44-fold to 80-fold increases in long-term follow-up cases (doss2004thethirdcase pages 1-4, gross19985aminolevulinicaciddehydratase pages 2-3). Doss et al., 2004, https://doi.org/10.1023/b:boli.0000037341.21975.9d (doss2004thethirdcase pages 1-4); Gross et al., 1998, https://doi.org/10.1093/clinchem/44.9.1892 (gross19985aminolevulinicaciddehydratase pages 2-3)
Key biochemical finding: PBG PBG is normal or only slightly elevated in ADP; this distinguishes ADP from most other acute hepatic porphyrias where PBG is typically elevated (graff2022casereportlack pages 1-2, wang2023agaclinicalpractice pages 3-5, doss2004thethirdcase pages 1-4). Graff et al., 2022, https://doi.org/10.3389/fgene.2022.867856 (graff2022casereportlack pages 1-2); Wang et al., 2023, https://doi.org/10.1053/j.gastro.2022.11.034 (wang2023agaclinicalpractice pages 3-5); Doss et al., 2004, https://doi.org/10.1023/b:boli.0000037341.21975.9d (doss2004thethirdcase pages 1-4)
Key biochemical finding: urinary porphyrins Urinary coproporphyrin III / coproporphyrin excretion is increased; one case had urinary coproporphyrin increased 76-fold and long-term cases had excessive urinary coproporphyrin excretion (graff2022casereportlack pages 1-2, gross19985aminolevulinicaciddehydratase pages 4-5, doss2004thethirdcase pages 1-4). Graff et al., 2022, https://doi.org/10.3389/fgene.2022.867856 (graff2022casereportlack pages 1-2); Gross et al., 1998, https://doi.org/10.1093/clinchem/44.9.1892 (gross19985aminolevulinicaciddehydratase pages 4-5); Doss et al., 2004, https://doi.org/10.1023/b:boli.0000037341.21975.9d (doss2004thethirdcase pages 1-4)
Key biochemical finding: erythrocyte Zn-protoporphyrin Erythrocyte zinc protoporphyrin is elevated/markedly increased; one case showed 5.4-fold elevation and case report/review also note increased erythrocyte zinc protoporphyrin (graff2022casereportlack pages 1-2, gross19985aminolevulinicaciddehydratase pages 4-5, doss2004thethirdcase pages 1-4). Graff et al., 2022, https://doi.org/10.3389/fgene.2022.867856 (graff2022casereportlack pages 1-2); Gross et al., 1998, https://doi.org/10.1093/clinchem/44.9.1892 (gross19985aminolevulinicaciddehydratase pages 4-5); Doss et al., 2004, https://doi.org/10.1023/b:boli.0000037341.21975.9d (doss2004thethirdcase pages 1-4)
Key biochemical finding: ALAD activity Profound ALAD deficiency in erythrocytes/lymphocytes, typically <10% of normal; examples include 10% activity in a 2004 case and <10% activity sustained over 20 years in 2 patients (gross19985aminolevulinicaciddehydratase pages 1-2, doss2004thethirdcase pages 1-4, pierro2021laboratorydiagnosisof pages 12-13). Gross et al., 1998, https://doi.org/10.1093/clinchem/44.9.1892 (gross19985aminolevulinicaciddehydratase pages 1-2); Doss et al., 2004, https://doi.org/10.1023/b:boli.0000037341.21975.9d (doss2004thethirdcase pages 1-4); Di Pierro et al., 2021, https://doi.org/10.3390/diagnostics11081343 (pierro2021laboratorydiagnosisof pages 12-13)
Hallmark clinical features Acute neurovisceral attacks with severe abdominal pain, peripheral neuropathy/weakness, polyneuropathy, autonomic/cardiovascular symptoms; can progress to paresis, respiratory paralysis/failure. No cutaneous manifestations are typical (graff2022casereportlack pages 1-2, ramanujam2015porphyriadiagnostics—part1 pages 9-11, gross19985aminolevulinicaciddehydratase pages 1-2, doss2004thethirdcase pages 1-4). Graff et al., 2022, https://doi.org/10.3389/fgene.2022.867856 (graff2022casereportlack pages 1-2); Ramanujam & Anderson, 2015, https://doi.org/10.1002/0471142905.hg1720s86 (ramanujam2015porphyriadiagnostics—part1 pages 9-11); Gross et al., 1998, https://doi.org/10.1093/clinchem/44.9.1892 (gross19985aminolevulinicaciddehydratase pages 1-2); Doss et al., 2004, https://doi.org/10.1023/b:boli.0000037341.21975.9d (doss2004thethirdcase pages 1-4)
Typical onset / rarity Usually childhood to adolescence; reported as extremely rare with ~6 cases in older review and ~8 documented worldwide in 2022 case report; historical reports noted all known cases male (graff2022casereportlack pages 1-2, ramanujam2015porphyriadiagnostics—part1 pages 9-11). Graff et al., 2022, https://doi.org/10.3389/fgene.2022.867856 (graff2022casereportlack pages 1-2); Ramanujam & Anderson, 2015, https://doi.org/10.1002/0471142905.hg1720s86 (ramanujam2015porphyriadiagnostics—part1 pages 9-11)
Recommended first-line diagnostic tests In suspected acute hepatic porphyria, first-line testing is random urine ALA and PBG corrected to creatinine; in ADP, elevated ALA with absent/minimal PBG rise should raise suspicion. Follow with porphyrin fractionation, erythrocyte ALAD activity assay, and molecular testing of ALAD (wang2023agaclinicalpractice pages 3-5, wang2023agaclinicalpractice pages 1-3, pierro2021laboratorydiagnosisof pages 2-4, pierro2021laboratorydiagnosisof pages 12-13). Wang et al., 2023, https://doi.org/10.1053/j.gastro.2022.11.034 (wang2023agaclinicalpractice pages 3-5, wang2023agaclinicalpractice pages 1-3); Di Pierro et al., 2021, https://doi.org/10.3390/diagnostics11081343 (pierro2021laboratorydiagnosisof pages 2-4, pierro2021laboratorydiagnosisof pages 12-13)
Additional diagnostic clues Plasma fluorescence scan may show emission peak around 618–622 nm in symptomatic ADP/AIP/HCP; blood lead level should be checked because lead poisoning can mimic ADP by inhibiting ALAD (pierro2021laboratorydiagnosisof pages 2-4, ramanujam2015porphyriadiagnostics—part1 pages 9-11, doss2004thethirdcase pages 1-4). Di Pierro et al., 2021, https://doi.org/10.3390/diagnostics11081343 (pierro2021laboratorydiagnosisof pages 2-4); Ramanujam & Anderson, 2015, https://doi.org/10.1002/0471142905.hg1720s86 (ramanujam2015porphyriadiagnostics—part1 pages 9-11); Doss et al., 2004, https://doi.org/10.1023/b:boli.0000037341.21975.9d (doss2004thethirdcase pages 1-4)
Differential diagnosis / triggers Important mimics and modifiers include lead poisoning, hereditary tyrosinemia type 1 (succinylacetone inhibits ALAD), zinc deficiency, alcohol, smoking, diabetes, and chronic renal failure. Lead displaces zinc from ALAD and can produce an ADP-like picture (ramanujam2015porphyriadiagnostics—part1 pages 9-11, balogun2023thehepaticporphyrias pages 3-5, gross19985aminolevulinicaciddehydratase pages 4-5). Ramanujam & Anderson, 2015, https://doi.org/10.1002/0471142905.hg1720s86 (ramanujam2015porphyriadiagnostics—part1 pages 9-11); Balogun & Nejak-Bowen, 2023, https://doi.org/10.1055/s-0043-1776760 (balogun2023thehepaticporphyrias pages 3-5); Gross et al., 1998, https://doi.org/10.1093/clinchem/44.9.1892 (gross19985aminolevulinicaciddehydratase pages 4-5)
Key treatment: hemin / heme arginate Best-supported acute and prophylactic treatment. Effective in several reported ADP patients; reduces urinary ALA and porphyrins and improves symptoms. Weekly haem arginate for 1 year produced sustained benefit in one case; long-term weekly prophylactic hemin reduced attacks in another but caused iron overload (doss2004thethirdcase pages 7-8, gross19985aminolevulinicaciddehydratase pages 1-2, doss2004thethirdcase pages 1-4, graff2022casereportlack pages 1-2). Doss et al., 2004, https://doi.org/10.1023/b:boli.0000037341.21975.9d (doss2004thethirdcase pages 7-8, doss2004thethirdcase pages 1-4); Gross et al., 1998, https://doi.org/10.1093/clinchem/44.9.1892 (gross19985aminolevulinicaciddehydratase pages 1-2); Graff et al., 2022, https://doi.org/10.3389/fgene.2022.867856 (graff2022casereportlack pages 1-2)
Key treatment: glucose / dextrose Used as part of acute attack management in AHPs; historical ADP cases improved with glucose plus heme arginate, but older review notes glucose loading alone was not effective in some young male ADP cases (wang2023agaclinicalpractice pages 1-3, gross19985aminolevulinicaciddehydratase pages 1-2, ramanujam2015porphyriadiagnostics—part1 pages 9-11). Wang et al., 2023, https://doi.org/10.1053/j.gastro.2022.11.034 (wang2023agaclinicalpractice pages 1-3); Gross et al., 1998, https://doi.org/10.1093/clinchem/44.9.1892 (gross19985aminolevulinicaciddehydratase pages 1-2); Ramanujam & Anderson, 2015, https://doi.org/10.1002/0471142905.hg1720s86 (ramanujam2015porphyriadiagnostics—part1 pages 9-11)
Key treatment: givosiran Included under broad AHP approvals/trials and ALAD-deficient patients were eligible for ENVISION, but no dedicated ALAD trial identified. Single ADP case report found no durable biochemical or clinical benefit after 6 months; attacks continued, though no liver adverse effects were observed in that patient (NCT03338816 chunk 1, graff2022casereportlack pages 2-4, graff2022casereportlack pages 1-2). ClinicalTrials.gov NCT03338816, 2017, https://clinicaltrials.gov/study/NCT03338816 (NCT03338816 chunk 1); Graff et al., 2022, https://doi.org/10.3389/fgene.2022.867856 (graff2022casereportlack pages 2-4, graff2022casereportlack pages 1-2)
Key treatment: hydroxyurea Not established, but reported as beneficial in one previous ADP case; considered/planned in 2022 case because ADP may have an erythropoietic component (graff2022casereportlack pages 1-2). Graff et al., 2022, https://doi.org/10.3389/fgene.2022.867856 (graff2022casereportlack pages 1-2)
Key treatment: liver transplantation Reserved for refractory AHP generally, but evidence in ADP is poor; one child with ADP did not benefit and died after liver transplantation according to historical reports/reviews (wang2023agaclinicalpractice pages 1-3, ramanujam2015porphyriadiagnostics—part1 pages 9-11, gross19985aminolevulinicaciddehydratase pages 4-5). Wang et al., 2023, https://doi.org/10.1053/j.gastro.2022.11.034 (wang2023agaclinicalpractice pages 1-3); Ramanujam & Anderson, 2015, https://doi.org/10.1002/0471142905.hg1720s86 (ramanujam2015porphyriadiagnostics—part1 pages 9-11); Gross et al., 1998, https://doi.org/10.1093/clinchem/44.9.1892 (gross19985aminolevulinicaciddehydratase pages 4-5)

Table: This table compiles the most actionable disease-definition, diagnostic, biochemical, and treatment facts for ALAD deficiency porphyria (Doss porphyria) using only gathered evidence. It is useful as a compact source for knowledge-base population and clinical differentiation from other acute hepatic porphyrias and lead toxicity.


Limitations of this report

  • Several requested identifiers (MONDO, Orphanet, ICD, MeSH) and population allele frequencies (gnomAD/ClinVar) were not present in the retrieved full-text evidence set; they are therefore not reported to avoid uncited or incorrect entries.
  • Evidence for ADP is dominated by case reports/very small series; conclusions about therapies such as givosiran or hydroxyurea remain low-certainty and should be interpreted cautiously. (graff2022casereportlack pages 1-2, NCT03338816 chunk 1)

References

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  2. (wang2023agaclinicalpractice pages 3-5): Bruce Wang, Herbert L. Bonkovsky, Joseph K. Lim, and Manisha Balwani. Aga clinical practice update on diagnosis and management of acute hepatic porphyrias: expert review. Gastroenterology, 164:484-491, Mar 2023. URL: https://doi.org/10.1053/j.gastro.2022.11.034, doi:10.1053/j.gastro.2022.11.034. This article has 91 citations and is from a highest quality peer-reviewed journal.

  3. (graff2022casereportlack pages 1-2): Erica Graff, Karl E. Anderson, and Cynthia Levy. Case report: lack of response to givosiran in a case of alad porphyria. Frontiers in Genetics, Aug 2022. URL: https://doi.org/10.3389/fgene.2022.867856, doi:10.3389/fgene.2022.867856. This article has 11 citations and is from a peer-reviewed journal.

  4. (ramanujam2015porphyriadiagnostics—part1 pages 9-11): Vaithamanithi‐Mudumbai Sadagopa Ramanujam and Karl Elmo Anderson. Porphyria diagnostics—part 1: a brief overview of the porphyrias. Current Protocols in Human Genetics, 86:17.20.1-17.20.26, Jul 2015. URL: https://doi.org/10.1002/0471142905.hg1720s86, doi:10.1002/0471142905.hg1720s86. This article has 220 citations.

  5. (gross19985aminolevulinicaciddehydratase pages 1-2): Ulrich Gross, Shigeru Sassa, Karl Jacob, Jean-Charles Deybach, Yves Nordmann, Margareta Frank, and Manfred O Doss. 5-aminolevulinic acid dehydratase deficiency porphyria: a twenty-year clinical and biochemical follow-up. Clinical Chemistry, 44:1892-1896, Sep 1998. URL: https://doi.org/10.1093/clinchem/44.9.1892, doi:10.1093/clinchem/44.9.1892. This article has 65 citations and is from a highest quality peer-reviewed journal.

  6. (doss2004thethirdcase pages 1-4): M. O. Doss, T. Stauch, U. Gross, M. Renz, R. Akagi, M. Doss‐Frank, H. P. Seelig, and S. Sassa. The third case of doss porphyria (δ-amino-levulinic acid dehydratase deficiency) in germany. Journal of Inherited Metabolic Disease, 27:529-536, Jul 2004. URL: https://doi.org/10.1023/b:boli.0000037341.21975.9d, doi:10.1023/b:boli.0000037341.21975.9d. This article has 68 citations and is from a peer-reviewed journal.

  7. (balogun2023thehepaticporphyrias pages 3-5): Oluwashanu Balogun and Kari Nejak-Bowen. The hepatic porphyrias: revealing the complexities of a rare disease. Seminars in Liver Disease, 43:446-459, Nov 2023. URL: https://doi.org/10.1055/s-0043-1776760, doi:10.1055/s-0043-1776760. This article has 10 citations and is from a peer-reviewed journal.

  8. (gross19985aminolevulinicaciddehydratase pages 4-5): Ulrich Gross, Shigeru Sassa, Karl Jacob, Jean-Charles Deybach, Yves Nordmann, Margareta Frank, and Manfred O Doss. 5-aminolevulinic acid dehydratase deficiency porphyria: a twenty-year clinical and biochemical follow-up. Clinical Chemistry, 44:1892-1896, Sep 1998. URL: https://doi.org/10.1093/clinchem/44.9.1892, doi:10.1093/clinchem/44.9.1892. This article has 65 citations and is from a highest quality peer-reviewed journal.

  9. (gross19985aminolevulinicaciddehydratase pages 2-3): Ulrich Gross, Shigeru Sassa, Karl Jacob, Jean-Charles Deybach, Yves Nordmann, Margareta Frank, and Manfred O Doss. 5-aminolevulinic acid dehydratase deficiency porphyria: a twenty-year clinical and biochemical follow-up. Clinical Chemistry, 44:1892-1896, Sep 1998. URL: https://doi.org/10.1093/clinchem/44.9.1892, doi:10.1093/clinchem/44.9.1892. This article has 65 citations and is from a highest quality peer-reviewed journal.

  10. (castelbon202404163functionalcharacterization pages 1-1): Francisco Javier Castelbón, Elena Di Pierro, Isabel Solares, Daniel Jericó, Javier Tomás Solera, Antoni Riera-Mestre, María Barreda, Annamaria Nicolli, Rafael Enríquez de Salamanca, Carlo Poci, Marta Gloria Fanlo-Maresma, Matías A Ávila, Matteo Marcacci, Pauline Harper, Encarna Guillén-Navarro, Giovanna Graziadei, Bodo Beck, Paolo Ventura, Montserrat Morales-Conejo, and Antonio Fontanellas. 04163 functional characterization of new pathogenic and lead-poisoning predisposing variants in ala dehydratase porphyria (adp). Poster 49, pages A42-A43, Sep 2024. URL: https://doi.org/10.1136/bmjgast-2024-icpp.75, doi:10.1136/bmjgast-2024-icpp.75. This article has 0 citations.

  11. (NCT03338816 chunk 1): ENVISION: A Study to Evaluate the Efficacy and Safety of Givosiran (ALN-AS1) in Patients With Acute Hepatic Porphyrias (AHP). Alnylam Pharmaceuticals. 2017. ClinicalTrials.gov Identifier: NCT03338816

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  13. (pierro2021laboratorydiagnosisof pages 2-4): Elena Di Pierro, Michele De Canio, Rosa Mercadante, Maria Savino, Francesca Granata, Dario Tavazzi, Anna Maria Nicolli, Andrea Trevisan, Stefano Marchini, and Silvia Fustinoni. Laboratory diagnosis of porphyria. Diagnostics, 11:1343, Jul 2021. URL: https://doi.org/10.3390/diagnostics11081343, doi:10.3390/diagnostics11081343. This article has 61 citations.

  14. (graff2022casereportlack pages 2-4): Erica Graff, Karl E. Anderson, and Cynthia Levy. Case report: lack of response to givosiran in a case of alad porphyria. Frontiers in Genetics, Aug 2022. URL: https://doi.org/10.3389/fgene.2022.867856, doi:10.3389/fgene.2022.867856. This article has 11 citations and is from a peer-reviewed journal.

  15. (graff2022casereportlack media 69c1e72f): Erica Graff, Karl E. Anderson, and Cynthia Levy. Case report: lack of response to givosiran in a case of alad porphyria. Frontiers in Genetics, Aug 2022. URL: https://doi.org/10.3389/fgene.2022.867856, doi:10.3389/fgene.2022.867856. This article has 11 citations and is from a peer-reviewed journal.

  16. (graff2022casereportlack media 97eb2153): Erica Graff, Karl E. Anderson, and Cynthia Levy. Case report: lack of response to givosiran in a case of alad porphyria. Frontiers in Genetics, Aug 2022. URL: https://doi.org/10.3389/fgene.2022.867856, doi:10.3389/fgene.2022.867856. This article has 11 citations and is from a peer-reviewed journal.

  17. (graff2022casereportlack media 0a38561c): Erica Graff, Karl E. Anderson, and Cynthia Levy. Case report: lack of response to givosiran in a case of alad porphyria. Frontiers in Genetics, Aug 2022. URL: https://doi.org/10.3389/fgene.2022.867856, doi:10.3389/fgene.2022.867856. This article has 11 citations and is from a peer-reviewed journal.

  18. (doss2004thethirdcase pages 7-8): M. O. Doss, T. Stauch, U. Gross, M. Renz, R. Akagi, M. Doss‐Frank, H. P. Seelig, and S. Sassa. The third case of doss porphyria (δ-amino-levulinic acid dehydratase deficiency) in germany. Journal of Inherited Metabolic Disease, 27:529-536, Jul 2004. URL: https://doi.org/10.1023/b:boli.0000037341.21975.9d, doi:10.1023/b:boli.0000037341.21975.9d. This article has 68 citations and is from a peer-reviewed journal.