Aromatic L-amino acid decarboxylase deficiency

Genetic MONDO:0012084 Pathograph 53 Neurotransmitter Metabolic Disorder Inborn Error of Metabolism Movement Disorder

Aromatic L-amino acid decarboxylase deficiency is an ultra-rare autosomal recessive neurometabolic disorder caused by biallelic pathogenic variants in DDC. Loss of aromatic L-amino acid decarboxylase activity disrupts dopamine, serotonin, norepinephrine, and epinephrine synthesis, causing early-onset hypotonia, global developmental delay, oculogyric crises, dystonia, autonomic dysfunction, and characteristic CSF neurotransmitter metabolite abnormalities.

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1
Inheritance
6
Pathophys.
38
Phenotypes
53
Pathograph
1
Genes
4
Treatments
1
Trials
9
References
1
Deep Research
👪

Inheritance

1
Autosomal recessive inheritance HP:0000007
AADC deficiency is inherited in an autosomal recessive manner and is caused by biallelic DDC variants.
Autosomal recessive inheritance
Show evidence (2 references)
ORPHA:35708 SUPPORT Other
"Autosomal recessive"
Orphanet lists autosomal recessive inheritance.
PMID:28100251 SUPPORT Human Clinical
"Aromatic L-amino acid decarboxylase deficiency (AADCD) is a rare, autosomal recessive neurometabolic disorder"
Consensus guideline supports autosomal recessive inheritance.
⚙

Pathophysiology

6
DDC Enzymatic Deficiency
Biallelic pathogenic variants in DDC reduce aromatic L-amino acid decarboxylase activity, blocking decarboxylation of neurotransmitter precursors.
DDC link
aromatic-L-amino-acid decarboxylase activity link ↓ DECREASED
Downstream
Biogenic Monoamine Synthesis Failure AADC catalyzes monoamine neurotransmitter synthesis from aromatic amino acid precursors.
Show evidence (2 references)
ORPHA:35708 SUPPORT Other
"DDC | dopa decarboxylase | hgnc:2719 | Disease-causing germline mutation(s) in"
Orphanet lists DDC as the disease-causing gene.
PMID:1357595 SUPPORT Human Clinical
"Activity of aromatic L-amino acid decarboxylase was virtually absent in a liver biopsy sample and greatly reduced in plasma."
The original case report directly documents absent or greatly reduced AADC activity.
Biogenic Monoamine Synthesis Failure
Loss of AADC activity decreases synthesis of dopamine, serotonin, norepinephrine, and epinephrine, producing central and peripheral monoamine deficiency.
dopamine biosynthetic process link ↓ DECREASED serotonin biosynthetic process link ↓ DECREASED norepinephrine biosynthetic process link ↓ DECREASED
Downstream
CSF Neurotransmitter Metabolite Signature Monoamine synthesis failure lowers downstream CSF metabolites and raises precursors.
Motor Circuit Dysfunction Dopamine deficiency disrupts basal-ganglia motor function.
Autonomic Dysfunction Peripheral and central monoamine deficiency contributes to autonomic symptoms.
Neurodevelopmental Impairment Early combined monoamine deficiency disrupts neurodevelopment.
Show evidence (3 references)
ORPHA:35708 SUPPORT Other
"impaired synthesis of dopamine, noradrenaline, adrenaline and serotonin."
Orphanet definition states the affected monoamine synthesis pathways.
PMID:28100251 SUPPORT Human Clinical
"leads to a severe combined deficiency of serotonin, dopamine, norepinephrine and epinephrine."
Consensus guideline supports combined monoamine deficiency.
PMID:19172410 SUPPORT Human Clinical
"resulting in generalized combined deficiency of serotonin, dopamine and catecholamines."
Clinical cohort describes generalized biogenic amine deficiency.
CSF Neurotransmitter Metabolite Signature
AADC deficiency produces a diagnostic CSF neurotransmitter pattern with low homovanillic acid and 5-hydroxyindoleacetic acid and elevated 3-ortho-methyldopa.
Downstream
Decreased CSF homovanillic acid concentration Reduced dopamine metabolism lowers CSF homovanillic acid.
Decreased CSF 5-hydroxyindolacetic acid concentration Reduced serotonin metabolism lowers CSF 5-hydroxyindoleacetic acid.
Increased circulating prolactin concentration Dopamine deficiency can disinhibit prolactin secretion.
Show evidence (2 references)
PMID:19172410 SUPPORT Human Clinical
"In CSF all patients revealed the pattern typical of AADC with decreased concentrations of homovanillic and 5-hydroxyindoleacetic acid and elevated concentration of 3-ortho-methyldopa."
Cohort data support the characteristic CSF metabolite pattern.
PMID:1357595 SUPPORT Human Clinical
"Concentrations of L-dopa, 3-methoxytyrosine, and 5-hydroxytryptophan were elevated in CSF, plasma, and urine."
Original report supports precursor accumulation caused by AADC deficiency.
Motor Circuit Dysfunction
Deficient dopamine synthesis in basal-ganglia motor circuits produces hypotonia, hypokinesia, dystonia, oculogyric crises, dyskinesia, and delayed motor development.
Downstream
Hypotonia
Oculogyric crisis
Dystonia
Hypokinesia
Dyskinesia
Poor head control
Motor delay
Ptosis AADC deficiency commonly includes ocular motor manifestations including ptosis.
Reduced tendon reflexes Motor-system dysfunction can include reduced tendon reflexes.
Limb hypertonia Basal-ganglia and motor-circuit dysfunction can manifest as limb hypertonia.
Babinski sign Central motor dysfunction can manifest as Babinski sign.
Tremor Movement-disorder circuitry can rarely manifest as tremor.
Joint contracture Chronic neuromotor impairment can contribute to joint contractures.
Show evidence (2 references)
PMID:28100251 SUPPORT Human Clinical
"key clinical symptoms are hypotonia, movement disorders (oculogyric crisis, dystonia, and hypokinesia), developmental delay, and autonomic symptoms."
Consensus guideline links the biochemical disorder to core motor symptoms.
PMID:30689738 SUPPORT Human Clinical
"a decrease in catecholamines and serotonin levels in the brain leads to developmental delay and movement disorders."
Gene-therapy study background links monoamine deficiency to motor and developmental manifestations.
Autonomic Dysfunction
Combined catecholamine and serotonin deficiency contributes to autonomic and extraneurological symptoms including hyperhidrosis, nasal congestion, hypersalivation/drooling, sleep disturbance, hypotension, and miosis.
Downstream
Hyperhidrosis
Nasal congestion
Drooling
Sleep abnormality
Hypotension
Miosis
Hypoglycemia
Constipation Dysautonomia and neuromotor dysfunction can manifest as constipation.
Diarrhea Gastrointestinal autonomic dysfunction can rarely manifest as diarrhea.
Gastroesophageal reflux Autonomic and neuromotor gastrointestinal dysfunction can contribute to reflux.
Show evidence (2 references)
PMID:19172410 SUPPORT Human Clinical
"All patients presented distinct extraneurological symptoms, such as hypersalivation, hyperhidrosis, nasal congestion, sleep disturbances and hypoglycaemia."
Clinical cohort supports autonomic and extraneurologic manifestations.
PMID:32409695 SUPPORT Human Clinical
"autonomic symptoms such as excessive sweating, nasal congestion and profuse nasal, and oropharyngeal secretions, were common in our patients."
Mainland China cohort supports frequent autonomic symptoms.
Neurodevelopmental Impairment
Early combined monoamine deficiency impairs developmental acquisition and is associated with global developmental delay, intellectual disability, seizures, feeding difficulties, and failure to thrive.
Downstream
Global developmental delay
Intellectual disability
Seizure
Feeding difficulties
Failure to thrive
Dysarthria
Atypical behavior Early serotonin and catecholamine deficiency is associated with behavioral disorders.
Autistic behavior Neurodevelopmental monoamine deficiency can include autistic behavior.
Irritability Non-motor neurobehavioral manifestations include irritability.
EEG abnormality Neurotransmitter imbalance and seizures can be accompanied by EEG abnormalities.
Dysphagia Neurodevelopmental and motor impairment can contribute to swallowing difficulty.
Short stature Chronic feeding difficulty and neurometabolic disease can contribute to impaired growth.
Show evidence (2 references)
PMID:36268467 SUPPORT Human Clinical
"Hypotonia and developmental delay are cardinal signs, reported as present in 73.9% and 72% of cases, respectively."
Systematic review supports common developmental delay and hypotonia.
PMID:30689738 SUPPORT Human Clinical
"In patients with aromatic l-amino acid decarboxylase (AADC) deficiency, a decrease in catecholamines and serotonin levels in the brain leads to developmental delay and movement disorders."
Gene-therapy study background links brain monoamine deficiency to developmental delay.
⬡

Pathograph

Use the checkboxes to hide or show graph categories. Hover nodes for evidence and cross-linked metadata.
Pathograph: causal mechanism network for Aromatic L-amino acid decarboxylase 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

38
Cardiovascular 1
Hypotension OCCASIONAL Hypotension (HP:0002615)
Show evidence (1 reference)
ORPHA:35708 SUPPORT Other
"HP:0002615 | Hypotension | Occasional (29-5%)"
Orphanet provides the phenotype association and frequency band.
Digestive 5
Diarrhea VERY_RARE Diarrhea (HP:0002014)
Show evidence (1 reference)
ORPHA:35708 SUPPORT Other
"HP:0002014 | Diarrhea | Very rare (<4-1%)"
Orphanet provides the phenotype association and frequency band.
Dysphagia OCCASIONAL Dysphagia (HP:0002015)
Show evidence (1 reference)
ORPHA:35708 SUPPORT Other
"HP:0002015 | Dysphagia | Occasional (29-5%)"
Orphanet provides the phenotype association and frequency band.
Constipation OCCASIONAL Constipation (HP:0002019)
Show evidence (1 reference)
ORPHA:35708 SUPPORT Other
"HP:0002019 | Constipation | Occasional (29-5%)"
Orphanet provides the phenotype association and frequency band.
Gastroesophageal reflux FREQUENT Gastroesophageal reflux (HP:0002020)
Show evidence (1 reference)
ORPHA:35708 SUPPORT Other
"HP:0002020 | Gastroesophageal reflux | Frequent (79-30%)"
Orphanet provides the phenotype association and frequency band.
Feeding difficulties FREQUENT Feeding difficulties (HP:0011968)
Show evidence (1 reference)
ORPHA:35708 SUPPORT Other
"HP:0011968 | Feeding difficulties | Frequent (79-30%)"
Orphanet provides the phenotype association and frequency band.
Eye 1
Ptosis OCCASIONAL Ptosis (HP:0000508)
Show evidence (2 references)
ORPHA:35708 SUPPORT Other
"HP:0000508 | Ptosis | Occasional (29-5%)"
Orphanet provides the phenotype association and frequency band.
PMID:36268467 SUPPORT Human Clinical
"Oculogyric crises were seen in 67% of patients while hypokinesia in 42% and ptosis in 26%."
Systematic review quantifies ptosis in the occasional range.
Head and Neck 2
Nasal congestion OCCASIONAL Nasal congestion (HP:0001742)
Show evidence (2 references)
ORPHA:35708 SUPPORT Other
"HP:0001742 | Nasal congestion | Occasional (29-5%)"
Orphanet provides the phenotype association and frequency band.
PMID:32409695 SUPPORT Human Clinical
"autonomic symptoms such as excessive sweating, nasal congestion and profuse nasal, and oropharyngeal secretions, were common in our patients."
Mainland China cohort supports nasal congestion as an autonomic manifestation.
Drooling OCCASIONAL Drooling (HP:0002307)
Show evidence (1 reference)
ORPHA:35708 SUPPORT Other
"HP:0002307 | Drooling | Occasional (29-5%)"
Orphanet provides the phenotype association and frequency band.
Integument 1
Hyperhidrosis FREQUENT Hyperhidrosis (HP:0000975)
Show evidence (2 references)
ORPHA:35708 SUPPORT Other
"HP:0000975 | Hyperhidrosis | Frequent (79-30%)"
Orphanet provides the phenotype association and frequency band.
PMID:19172410 SUPPORT Human Clinical
"All patients presented distinct extraneurological symptoms, such as hypersalivation, hyperhidrosis, nasal congestion, sleep disturbances and hypoglycaemia."
Clinical cohort supports hyperhidrosis as an AADC deficiency manifestation.
Metabolism 1
Hypoglycemia OCCASIONAL Hypoglycemia (HP:0001943)
Show evidence (2 references)
ORPHA:35708 SUPPORT Other
"HP:0001943 | Hypoglycemia | Occasional (29-5%)"
Orphanet provides the phenotype association and frequency band.
PMID:19172410 SUPPORT Human Clinical
"All patients presented distinct extraneurological symptoms, such as hypersalivation, hyperhidrosis, nasal congestion, sleep disturbances and hypoglycaemia."
Clinical cohort documents hypoglycemia among extraneurological symptoms.
Musculoskeletal 2
Hypotonia FREQUENT Hypotonia (HP:0001252)
Show evidence (2 references)
ORPHA:35708 SUPPORT Other
"HP:0001252 | Hypotonia | Frequent (79-30%)"
Orphanet provides the phenotype association and frequency band.
PMID:36268467 SUPPORT Human Clinical
"Hypotonia and developmental delay are cardinal signs, reported as present in 73.9% and 72% of cases, respectively."
Systematic review quantifies hypotonia in the frequent range.
Joint contracture VERY_RARE Joint contracture (HP:0034392)
Show evidence (1 reference)
ORPHA:35708 SUPPORT Other
"HP:0034392 | Joint contracture | Very rare (<4-1%)"
Orphanet provides the phenotype association and frequency band.
Nervous System 13
Atypical behavior FREQUENT Atypical behavior (HP:0000708)
Show evidence (2 references)
ORPHA:35708 SUPPORT Other
"HP:0000708 | Atypical behavior | Frequent (79-30%)"
Orphanet provides the phenotype association and frequency band.
PMID:36268467 SUPPORT Human Clinical
"With 37% and 30% of patients reported being affected by sleep and behavioural disorders"
Systematic review supports frequent behavioral manifestations.
Autistic behavior OCCASIONAL Autistic behavior (HP:0000729)
Show evidence (1 reference)
ORPHA:35708 SUPPORT Other
"HP:0000729 | Autistic behavior | Occasional (29-5%)"
Orphanet provides the phenotype association and frequency band.
Irritability FREQUENT Irritability (HP:0000737)
Show evidence (1 reference)
ORPHA:35708 SUPPORT Other
"HP:0000737 | Irritability | Frequent (79-30%)"
Orphanet provides the phenotype association and frequency band.
Intellectual disability FREQUENT Intellectual disability (HP:0001249)
Show evidence (1 reference)
ORPHA:35708 SUPPORT Other
"HP:0001249 | Intellectual disability | Frequent (79-30%)"
Orphanet provides the phenotype association and frequency band.
Seizure FREQUENT Seizure (HP:0001250)
Show evidence (2 references)
ORPHA:35708 SUPPORT Other
"HP:0001250 | Seizure | Frequent (79-30%)"
Orphanet provides the phenotype association and frequency band.
PMID:19172410 SUPPORT Human Clinical
"Three patients had single seizures."
Clinical cohort documents seizures in AADC deficiency.
Dysarthria OCCASIONAL Dysarthria (HP:0001260)
Show evidence (1 reference)
ORPHA:35708 SUPPORT Other
"HP:0001260 | Dysarthria | Occasional (29-5%)"
Orphanet provides the phenotype association and frequency band.
Global developmental delay VERY_FREQUENT Global developmental delay (HP:0001263)
Show evidence (2 references)
ORPHA:35708 SUPPORT Other
"HP:0001263 | Global developmental delay | Very frequent (99-80%)"
Orphanet provides the phenotype association and frequency band.
PMID:36268467 SUPPORT Human Clinical
"Hypotonia and developmental delay are cardinal signs, reported as present in 73.9% and 72% of cases, respectively."
Systematic review supports developmental delay as a cardinal sign.
Motor delay FREQUENT Motor delay (HP:0001270)
Show evidence (1 reference)
ORPHA:35708 SUPPORT Other
"HP:0001270 | Motor delay | Frequent (79-30%)"
Orphanet provides the phenotype association and frequency band.
Dystonia FREQUENT Dystonia (HP:0001332)
Show evidence (2 references)
ORPHA:35708 SUPPORT Other
"HP:0001332 | Dystonia | Frequent (79-30%)"
Orphanet provides the phenotype association and frequency band.
PMID:28100251 SUPPORT Human Clinical
"movement disorders (oculogyric crisis, dystonia, and hypokinesia)"
Consensus guideline lists dystonia as a key movement disorder.
Tremor VERY_RARE Tremor (HP:0001337)
Show evidence (1 reference)
ORPHA:35708 SUPPORT Other
"HP:0001337 | Tremor | Very rare (<4-1%)"
Orphanet provides the phenotype association and frequency band.
EEG abnormality OCCASIONAL EEG abnormality (HP:0002353)
Show evidence (1 reference)
ORPHA:35708 SUPPORT Other
"HP:0002353 | EEG abnormality | Occasional (29-5%)"
Orphanet provides the phenotype association and frequency band.
Sleep abnormality FREQUENT Sleep disturbance (HP:0002360)
Show evidence (2 references)
ORPHA:35708 SUPPORT Other
"HP:0002360 | Sleep abnormality | Frequent (79-30%)"
Orphanet provides the phenotype association and frequency band.
PMID:36268467 SUPPORT Human Clinical
"With 37% and 30% of patients reported being affected by sleep and behavioural disorders"
Systematic review supports sleep abnormality in the frequent range.
Dyskinesia OCCASIONAL Dyskinesia (HP:0100660)
Show evidence (1 reference)
ORPHA:35708 SUPPORT Other
"HP:0100660 | Dyskinesia | Occasional (29-5%)"
Orphanet provides the phenotype association and frequency band.
Growth 2
Failure to thrive FREQUENT Failure to thrive (HP:0001508)
Show evidence (1 reference)
ORPHA:35708 SUPPORT Other
"HP:0001508 | Failure to thrive | Frequent (79-30%)"
Orphanet provides the phenotype association and frequency band.
Short stature OCCASIONAL Short stature (HP:0004322)
Show evidence (1 reference)
ORPHA:35708 SUPPORT Other
"HP:0004322 | Short stature | Occasional (29-5%)"
Orphanet provides the phenotype association and frequency band.
Other 10
Miosis OCCASIONAL Miosis (HP:0000616)
Show evidence (1 reference)
ORPHA:35708 SUPPORT Other
"HP:0000616 | Miosis | Occasional (29-5%)"
Orphanet provides the phenotype association and frequency band.
Increased circulating prolactin concentration OCCASIONAL Increased circulating prolactin concentration (HP:0000870)
Show evidence (1 reference)
ORPHA:35708 SUPPORT Other
"HP:0000870 | Increased circulating prolactin concentration | Occasional (29-5%)"
Orphanet provides the phenotype association and frequency band.
Reduced tendon reflexes OCCASIONAL Reduced tendon reflexes (HP:0001315)
Show evidence (1 reference)
ORPHA:35708 SUPPORT Other
"HP:0001315 | Reduced tendon reflexes | Occasional (29-5%)"
Orphanet provides the phenotype association and frequency band.
Hypokinesia OCCASIONAL Hypokinesia (HP:0002375)
Show evidence (1 reference)
ORPHA:35708 SUPPORT Other
"HP:0002375 | Hypokinesia | Occasional (29-5%)"
Orphanet provides the phenotype association and frequency band.
Poor head control FREQUENT Poor head control (HP:0002421)
Show evidence (1 reference)
ORPHA:35708 SUPPORT Other
"HP:0002421 | Poor head control | Frequent (79-30%)"
Orphanet provides the phenotype association and frequency band.
Limb hypertonia OCCASIONAL Limb hypertonia (HP:0002509)
Show evidence (1 reference)
ORPHA:35708 SUPPORT Other
"HP:0002509 | Limb hypertonia | Occasional (29-5%)"
Orphanet provides the phenotype association and frequency band.
Babinski sign OCCASIONAL Babinski sign (HP:0003487)
Show evidence (1 reference)
ORPHA:35708 SUPPORT Other
"HP:0003487 | Babinski sign | Occasional (29-5%)"
Orphanet provides the phenotype association and frequency band.
Decreased CSF homovanillic acid concentration VERY_FREQUENT Decreased CSF homovanillic acid concentration (HP:0003785)
Show evidence (2 references)
ORPHA:35708 SUPPORT Other
"HP:0003785 | Decreased CSF homovanillic acid concentration | Very frequent (99-80%)"
Orphanet provides the phenotype association and frequency band.
PMID:19172410 SUPPORT Human Clinical
"In CSF all patients revealed the pattern typical of AADC with decreased concentrations of homovanillic and 5-hydroxyindoleacetic acid and elevated concentration of 3-ortho-methyldopa."
Clinical cohort supports decreased CSF homovanillic acid.
Oculogyric crisis FREQUENT Oculogyric crisis (HP:0010553)
Show evidence (2 references)
ORPHA:35708 SUPPORT Other
"HP:0010553 | Oculogyric crisis | Frequent (79-30%)"
Orphanet provides the phenotype association and frequency band.
PMID:36268467 SUPPORT Human Clinical
"Oculogyric crises were seen in 67% of patients while hypokinesia in 42% and ptosis in 26%."
Systematic review quantifies oculogyric crises in the frequent range.
Decreased CSF 5-hydroxyindolacetic acid concentration VERY_FREQUENT Decreased CSF 5-hydroxyindolacetic acid concentration (HP:0025455)
Show evidence (2 references)
ORPHA:35708 SUPPORT Other
"HP:0025455 | Decreased CSF 5-hydroxyindolacetic acid concentration | Very frequent (99-80%)"
Orphanet provides the phenotype association and frequency band.
PMID:19172410 SUPPORT Human Clinical
"In CSF all patients revealed the pattern typical of AADC with decreased concentrations of homovanillic and 5-hydroxyindoleacetic acid and elevated concentration of 3-ortho-methyldopa."
Clinical cohort supports decreased CSF 5-hydroxyindoleacetic acid.
🧬

Genetic Associations

1
DDC (Biallelic pathogenic variants)
Show evidence (4 references)
ORPHA:35708 SUPPORT Other
"DDC | dopa decarboxylase | hgnc:2719 | Disease-causing germline mutation(s) in"
Orphanet lists DDC as the disease-causing gene.
PMID:36268467 SUPPORT Human Clinical
"caused by pathogenic homozygous or compound heterozygous variants in the dopa decarboxylase (DDC) gene."
Systematic review supports biallelic pathogenic DDC variants.
PMID:32409695 SUPPORT Human Clinical
"Twenty-three patients with clinical features of AADCD and DDC gene variants were recruited."
Mainland China cohort supports disease association with DDC variants.
+ 1 more reference
💊

Treatments

4
Eladocagene exuparvovec gene therapy
Action: gene therapy MAXO:0001001
Agent: eladocagene exuparvovec ↗
Eladocagene exuparvovec delivers DDC via an adeno-associated viral vector to the putamen, aiming to restore dopamine synthesis and improve motor, developmental, and oculogyric manifestations.
Mechanism Target:
RESTORES DDC Enzymatic Deficiency — Gene addition supplies the human DDC coding sequence to restore AADC activity in the putamen.
Show evidence (1 reference)
PMID:30689738 SUPPORT Human Clinical
"The patients received a total of 2 × 1011 vector genomes of adeno-associated virus vector harbouring DDC via bilateral intraputaminal infusions."
Open-label clinical study describes AAV vector delivery of DDC to the putamen.
RESTORES Biogenic Monoamine Synthesis Failure — Restored putaminal DDC expression increases dopamine synthesis.
Show evidence (1 reference)
PMID:30689738 SUPPORT Human Clinical
"The restoration of dopamine synthesis in the putamen via gene transfer provides transformative medical benefit across all patient ages"
Clinical study supports restoration of putaminal dopamine synthesis.
Show evidence (3 references)
PMID:30689738 SUPPORT Human Clinical
"At up to 2 years after gene therapy, the motor function was remarkably improved in all patients."
Open-label phase 1/2 study supports motor improvement after AAV-DDC gene therapy.
PMID:30689738 SUPPORT Human Clinical
"Dystonia disappeared and oculogyric crisis was markedly decreased in all patients."
Gene therapy improved key movement disorder manifestations.
DOI:10.1001/jama.2024.28666 SUPPORT Human Clinical
"US Food and Drug Administration approval of Kebilidi, eladocagene exuparvovec, for the treatment of aromatic L-amino acid decarboxylase deficiency in adult and pediatric patients."
JAMA Insights reports FDA approval for AADC deficiency.
Pyridoxine pharmacotherapy
Action: Pharmacotherapy NCIT:C15986
Agent: pyridoxine ↗
Pyridoxine or pyridoxal phosphate is used as cofactor-directed symptomatic therapy, often in combination with dopamine agonists and MAO inhibitors; clinical responses are variable.
Mechanism Target:
MODULATES DDC Enzymatic Deficiency — Pyridoxine provides vitamin B6 cofactor support for residual AADC activity.
Show evidence (2 references)
PMID:19172410 SUPPORT Human Clinical
"Drug regimes consisted of vitamin B6, dopamine agonists, MAO inhibitors and anticholinergics in different combinations."
Clinical cohort lists vitamin B6 among AADC deficiency drug regimens.
PMID:32409695 SUPPORT Human Clinical
"Eighteen patients (78.3%) got various degree of improvement after using pyridoxine monotherapy or different combination of pyridoxine, dopamine agonists, and monoamine oxidase (MAO) inhibitors."
Mainland China cohort supports partial improvement with pyridoxine-based regimens.
Dopamine agonist and MAO inhibitor pharmacotherapy
Action: Pharmacotherapy NCIT:C15986
Agent: dopamine agonist ↗ monoamine oxidase inhibitor ↗
Dopamine agonists and monoamine oxidase inhibitors are used as symptomatic neurotransmitter-directed treatment classes, sometimes with vitamin B6 and anticholinergics.
Mechanism Target:
MODULATES Biogenic Monoamine Synthesis Failure — These drugs augment dopaminergic signaling or reduce monoamine breakdown despite impaired synthesis.
Show evidence (3 references)
PMID:1357595 SUPPORT Human Clinical
"Treatment with either bromocriptine or tranylcypromine stopped the abnormal eye movements; tranylcypromine treatment also improved muscle tone"
Original cases improved with dopamine agonist and MAO inhibitor therapy.
PMID:19172410 SUPPORT Human Clinical
"Drug regimes consisted of vitamin B6, dopamine agonists, MAO inhibitors and anticholinergics in different combinations."
Clinical cohort supports dopamine agonist and MAO inhibitor use.
PMID:32409695 SUPPORT Human Clinical
"Eighteen patients (78.3%) got various degree of improvement after using pyridoxine monotherapy or different combination of pyridoxine, dopamine agonists, and monoamine oxidase (MAO) inhibitors."
Mainland China cohort supports partial improvement with combination regimens.
Multidisciplinary supportive care
Action: supportive care MAXO:0000950
Supportive care addresses feeding, sleep, mobility, seizures, and other neurologic or autonomic complications while disease-directed and symptomatic therapies are optimized.
Target Phenotypes: Feeding difficulties ↗ Sleep abnormality ↗ Seizure ↗ Hypotonia ↗
Show evidence (1 reference)
PMID:28100251 SUPPORT Other
"practical recommendations on clinical diagnosis, laboratory diagnosis, imaging and electroencephalograpy, medical treatments and non-medical treatments."
Consensus guideline supports medical and non-medical care recommendations for AADC deficiency.
🔬

Biochemical Markers

4
Low CSF homovanillic acid (DECREASED)
Pathograph Readouts
Readout Of CSF Neurotransmitter Metabolite Signature Negative Diagnostic
Decreased CSF HVA reports the dopamine-metabolite arm of the AADC deficiency CSF signature.
Show evidence (1 reference)
PMID:19172410 SUPPORT Human Clinical
"In CSF all patients revealed the pattern typical of AADC with decreased concentrations of homovanillic and 5-hydroxyindoleacetic acid and elevated concentration of 3-ortho-methyldopa."
Clinical cohort supports decreased CSF homovanillic acid in the diagnostic profile.
Low CSF 5-hydroxyindoleacetic acid (DECREASED)
Pathograph Readouts
Readout Of CSF Neurotransmitter Metabolite Signature Negative Diagnostic
Decreased CSF 5-HIAA reports the serotonin-metabolite arm of the AADC deficiency CSF signature.
Show evidence (1 reference)
PMID:19172410 SUPPORT Human Clinical
"In CSF all patients revealed the pattern typical of AADC with decreased concentrations of homovanillic and 5-hydroxyindoleacetic acid and elevated concentration of 3-ortho-methyldopa."
Clinical cohort supports decreased CSF 5-hydroxyindoleacetic acid in the diagnostic profile.
Elevated CSF 3-O-methyldopa (INCREASED)
Pathograph Readouts
Readout Of CSF Neurotransmitter Metabolite Signature Positive Diagnostic
Elevated 3-OMD reports precursor shunting in the AADC deficiency CSF signature.
Show evidence (1 reference)
PMID:19172410 SUPPORT Human Clinical
"In CSF all patients revealed the pattern typical of AADC with decreased concentrations of homovanillic and 5-hydroxyindoleacetic acid and elevated concentration of 3-ortho-methyldopa."
Clinical cohort supports elevated 3-ortho-methyldopa in the diagnostic CSF profile.
Reduced plasma AADC activity (DECREASED)
Pathograph Readouts
Readout Of DDC Enzymatic Deficiency Negative Diagnostic
Reduced plasma AADC activity reports the primary DDC enzyme deficiency.
Show evidence (2 references)
PMID:19172410 SUPPORT Human Clinical
"Diagnosis was confirmed by measurement of AADC activity in plasma in all patients."
Clinical cohort supports plasma AADC activity as an enzymatic diagnostic readout.
PMID:1357595 SUPPORT Human Clinical
"Activity of aromatic L-amino acid decarboxylase was virtually absent in a liver biopsy sample and greatly reduced in plasma."
Original report supports reduced AADC activity in plasma and tissue.
🔬

Clinical Trials

1
NCT04903288 PHASE_II ACTIVE_NOT_RECRUITING
Phase 2 open-label trial assessing pharmacodynamics and safety of eladocagene exuparvovec administered with an MR-compatible ventricular cannula in pediatric AADC deficiency, with extension follow-up for motor development, AADC-specific symptoms, and long-term safety and efficacy.
Target Phenotypes: Motor delay ↗ Decreased CSF homovanillic acid concentration ↗
Show evidence (2 references)
clinicaltrials:NCT04903288 SUPPORT Human Clinical
"The primary objectives of the trial phase are to assess the pharmacodynamics (PD) of eladocagene exuparvovec treatment by evaluation of homovanillic acid (HVA) levels"
ClinicalTrials.gov identifies pharmacodynamic assessment of eladocagene exuparvovec in AADC deficiency.
clinicaltrials:NCT04903288 SUPPORT Human Clinical
"The extension phase is designed to capture additional clinical information for eladocagene exuparvovec through study evaluations, changes in motor development, AADC-specific symptoms, and other PD measures."
Trial follow-up includes motor development, AADC-specific symptoms, and pharmacodynamic measures.
{ }

Source YAML

click to show 
name: Aromatic L-amino acid decarboxylase deficiency
creation_date: "2026-05-06T21:19:10Z"
updated_date: "2026-05-18T11:52:22Z"
category: Genetic
parents:
- Neurotransmitter Metabolic Disorder
- Inborn Error of Metabolism
- Movement Disorder
synonyms:
- AADC deficiency
description: >-
  Aromatic L-amino acid decarboxylase deficiency is an ultra-rare autosomal
  recessive neurometabolic disorder caused by biallelic pathogenic variants in
  DDC. Loss of aromatic L-amino acid decarboxylase activity disrupts dopamine,
  serotonin, norepinephrine, and epinephrine synthesis, causing early-onset
  hypotonia, global developmental delay, oculogyric crises, dystonia, autonomic
  dysfunction, and characteristic CSF neurotransmitter metabolite abnormalities.
disease_term:
  preferred_term: aromatic L-amino acid decarboxylase deficiency
  term:
    id: MONDO:0012084
    label: aromatic L-amino acid decarboxylase deficiency
references:
- reference: ORPHA:35708
  title: Aromatic L-amino acid decarboxylase deficiency
  found_in:
  - Aromatic_L_Amino_Acid_Decarboxylase_Deficiency-deep-research-fallback.md
  findings:
  - statement: >-
      Orphanet defines AADC deficiency as a rare severe genetic neurometabolic
      disorder caused by impaired catecholamine and serotonin synthesis.
    supporting_text: >-
      A rare, severe, genetic neurometabolic disorder associated with clinical
      manifestations related to impaired synthesis of dopamine, noradrenaline,
      adrenaline and serotonin.
- reference: PMID:28100251
  title: Consensus guideline for the diagnosis and treatment of aromatic l-amino acid decarboxylase (AADC) deficiency.
  found_in:
  - Aromatic_L_Amino_Acid_Decarboxylase_Deficiency-deep-research-fallback.md
  findings:
  - statement: >-
      The international consensus guideline supports autosomal recessive
      inheritance, early onset, key motor/autonomic symptoms, laboratory
      diagnosis, imaging/EEG considerations, and medical management.
    supporting_text: >-
      In the face of limited definitive evidence, we constructed practical
      recommendations on clinical diagnosis, laboratory diagnosis, imaging and
      electroencephalograpy, medical treatments and non-medical treatments.
- reference: PMID:19172410
  title: "Aromatic L-amino acid decarboxylase deficiency: clinical features, drug therapy and follow-up."
  found_in:
  - Aromatic_L_Amino_Acid_Decarboxylase_Deficiency-deep-research-fallback.md
  findings:
  - statement: >-
      A German clinical cohort supports the combined serotonin/dopamine/
      catecholamine deficiency, core neurologic and extraneurologic features,
      characteristic CSF profile, plasma enzyme confirmation, and symptomatic
      drug treatment classes.
    supporting_text: >-
      AADC deficiency is a disorder of biogenic amine metabolism resulting in
      generalized combined deficiency of serotonin, dopamine and catecholamines.
- reference: PMID:36268467
  title: "Clinical Features in Aromatic L-Amino Acid Decarboxylase (AADC) Deficiency: A Systematic Review."
  found_in:
  - Aromatic_L_Amino_Acid_Decarboxylase_Deficiency-deep-research-fallback.md
  findings:
  - statement: >-
      A systematic review of 261 molecularly or biochemically diagnosed patients
      supports DDC causation, early onset, frequent hypotonia, developmental
      delay, oculogyric crises, hypokinesia, ptosis, dysautonomia,
      gastrointestinal symptoms, sleep disorders, and behavioral disorders.
    supporting_text: >-
      By analysing 261 patients from 41 papers with molecular and/or
      biochemical diagnosis of AADC deficiency for which individuality could be
      determined with certainty, we found symptom onset to occur in the first 6
      months of life in 93% of cases.
- reference: PMID:30689738
  title: Gene therapy improves motor and mental function of aromatic l-amino acid decarboxylase deficiency.
  found_in:
  - Aromatic_L_Amino_Acid_Decarboxylase_Deficiency-deep-research-fallback.md
  findings:
  - statement: >-
      An open-label phase 1/2 intraputaminal AAV-DDC study supports restored
      putaminal dopamine synthesis and improved motor, oculogyric, dystonic,
      cognitive, and verbal function after gene therapy.
    supporting_text: >-
      The restoration of dopamine synthesis in the putamen via gene transfer
      provides transformative medical benefit across all patient ages,
      genotypes, and disease severities included in this study.
- reference: PMID:1357595
  title: "Aromatic L-amino acid decarboxylase deficiency: clinical features, diagnosis, and treatment of a new inborn error of neurotransmitter amine synthesis."
  found_in:
  - Aromatic_L_Amino_Acid_Decarboxylase_Deficiency-deep-research-fallback.md
  findings:
  - statement: >-
      The original case report documents severe hypotonia, oculogyric crises,
      absent/reduced AADC activity, reduced biogenic amines, elevated precursors,
      and partial response to bromocriptine/tranylcypromine-based therapy.
    supporting_text: >-
      Activity of aromatic L-amino acid decarboxylase was virtually absent in a
      liver biopsy sample and greatly reduced in plasma.
- reference: PMID:32409695
  title: The genetic and clinical characteristics of aromatic L-amino acid decarboxylase deficiency in mainland China.
  found_in:
  - Aromatic_L_Amino_Acid_Decarboxylase_Deficiency-deep-research-fallback.md
  findings:
  - statement: >-
      A 23-patient mainland China cohort supports DDC variants, early onset,
      hypotonia, oculogyric crises, autonomic symptoms, and frequent partial
      improvement with pyridoxine, dopamine agonist, and MAO inhibitor regimens.
    supporting_text: >-
      Eighteen patients (78.3%) got various degree of improvement after using
      pyridoxine monotherapy or different combination of pyridoxine, dopamine
      agonists, and monoamine oxidase (MAO) inhibitors.
- reference: DOI:10.1001/jama.2024.28666
  title: Eladocagene Exuparvovec for Aromatic L-Amino Acid Decarboxylase Deficiency
  found_in:
  - Aromatic_L_Amino_Acid_Decarboxylase_Deficiency-deep-research-fallback.md
  findings:
  - statement: >-
      JAMA Insights reports FDA approval of Kebilidi, eladocagene exuparvovec,
      for AADC deficiency in adult and pediatric patients.
    supporting_text: >-
      This JAMA Insights discusses the US Food and Drug Administration approval
      of Kebilidi, eladocagene exuparvovec, for the treatment of aromatic
      L-amino acid decarboxylase deficiency in adult and pediatric patients.
- reference: clinicaltrials:NCT04903288
  title: An Open-Label Trial to Address the Safety of the SmartFlow MR-Compatible Ventricular Cannula for Administering Eladocagene Exuparvovec to Pediatric Subjects
  found_in:
  - Aromatic_L_Amino_Acid_Decarboxylase_Deficiency-deep-research-fallback.md
  findings:
  - statement: >-
      ClinicalTrials.gov documents an active-not-recruiting phase 2 trial of
      eladocagene exuparvovec in pediatric AADC deficiency.
    supporting_text: >-
      The primary objectives of the trial phase are to assess the
      pharmacodynamics (PD) of eladocagene exuparvovec treatment by evaluation
      of homovanillic acid (HVA) levels and to assess the safety of the
      SmartFlow magnetic resonance compatible ventricular cannula.
prevalence:
- population: Worldwide
  percentage: Less than 1 per 1,000,000
  notes: >-
    Orphanet classifies AADC deficiency as ultra-rare, with worldwide point
    prevalence below one per million.
  evidence:
  - reference: ORPHA:35708
    reference_title: "Aromatic L-amino acid decarboxylase deficiency"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "<1 / 1 000 000 | Worldwide | Point prevalence | PMID:30689738"
    explanation: Orphanet reports worldwide point prevalence below one per million.
progression:
- phase: Early-onset neurometabolic disease
  notes: >-
    Most reported patients have symptom onset in the first six months of life,
    with early hypotonia, oculogyric crises, global developmental delay, and
    autonomic dysfunction.
  evidence:
  - reference: ORPHA:35708
    reference_title: "Aromatic L-amino acid decarboxylase deficiency"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Age of onset: Infancy"
    explanation: Orphanet lists infancy as an age of onset.
  - reference: ORPHA:35708
    reference_title: "Aromatic L-amino acid decarboxylase deficiency"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Age of onset: Neonatal"
    explanation: Orphanet also lists neonatal onset.
  - reference: PMID:36268467
    reference_title: "Clinical Features in Aromatic L-Amino Acid Decarboxylase (AADC) Deficiency: A Systematic Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "we found symptom onset to occur in the first 6 months of life in 93% of cases."
    explanation: Systematic review supports very early symptom onset in most patients.
inheritance:
- name: Autosomal recessive inheritance
  inheritance_term:
    preferred_term: Autosomal recessive inheritance
    term:
      id: HP:0000007
      label: Autosomal recessive inheritance
  description: >-
    AADC deficiency is inherited in an autosomal recessive manner and is caused
    by biallelic DDC variants.
  evidence:
  - reference: ORPHA:35708
    reference_title: "Aromatic L-amino acid decarboxylase deficiency"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Autosomal recessive"
    explanation: Orphanet lists autosomal recessive inheritance.
  - reference: PMID:28100251
    reference_title: "Consensus guideline for the diagnosis and treatment of aromatic l-amino acid decarboxylase (AADC) deficiency."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Aromatic L-amino acid decarboxylase deficiency (AADCD) is a rare, autosomal recessive neurometabolic disorder"
    explanation: Consensus guideline supports autosomal recessive inheritance.
genetic:
- name: DDC
  association: Biallelic pathogenic variants
  presence: Positive
  gene_term:
    preferred_term: DDC
    term:
      id: hgnc:2719
      label: DDC
  notes: >-
    DDC encodes dopa decarboxylase/aromatic L-amino acid decarboxylase; loss of
    function produces combined monoamine neurotransmitter deficiency.
  evidence:
  - reference: ORPHA:35708
    reference_title: "Aromatic L-amino acid decarboxylase deficiency"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "DDC | dopa decarboxylase | hgnc:2719 | Disease-causing germline mutation(s) in"
    explanation: Orphanet lists DDC as the disease-causing gene.
  - reference: PMID:36268467
    reference_title: "Clinical Features in Aromatic L-Amino Acid Decarboxylase (AADC) Deficiency: A Systematic Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "caused by pathogenic homozygous or compound heterozygous variants in the dopa decarboxylase (DDC) gene."
    explanation: Systematic review supports biallelic pathogenic DDC variants.
  - reference: PMID:32409695
    reference_title: "The genetic and clinical characteristics of aromatic L-amino acid decarboxylase deficiency in mainland China."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Twenty-three patients with clinical features of AADCD and DDC gene variants were recruited."
    explanation: Mainland China cohort supports disease association with DDC variants.
  - reference: CGGV:assertion_1dea33e3-7cf6-47f9-aa52-2525b439031a-2022-02-25T170000.000Z
    reference_title: "DDC / aromatic L-amino acid decarboxylase deficiency (Definitive)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "DDC | HGNC:2719 | aromatic L-amino acid decarboxylase deficiency | MONDO:0012084 | AR | Definitive"
    explanation: ClinGen classifies the DDC-aromatic L-amino acid decarboxylase deficiency gene-disease relationship as definitive with autosomal recessive inheritance.
pathophysiology:
- name: DDC Enzymatic Deficiency
  description: >-
    Biallelic pathogenic variants in DDC reduce aromatic L-amino acid
    decarboxylase activity, blocking decarboxylation of neurotransmitter
    precursors.
  genes:
  - preferred_term: DDC
    term:
      id: hgnc:2719
      label: DDC
  molecular_functions:
  - preferred_term: aromatic-L-amino-acid decarboxylase activity
    term:
      id: GO:0004058
      label: aromatic-L-amino-acid decarboxylase activity
    modifier: DECREASED
  evidence:
  - reference: ORPHA:35708
    reference_title: "Aromatic L-amino acid decarboxylase deficiency"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "DDC | dopa decarboxylase | hgnc:2719 | Disease-causing germline mutation(s) in"
    explanation: Orphanet lists DDC as the disease-causing gene.
  - reference: PMID:1357595
    reference_title: "Aromatic L-amino acid decarboxylase deficiency: clinical features, diagnosis, and treatment of a new inborn error of neurotransmitter amine synthesis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Activity of aromatic L-amino acid decarboxylase was virtually absent in a liver biopsy sample and greatly reduced in plasma."
    explanation: The original case report directly documents absent or greatly reduced AADC activity.
  downstream:
  - target: Biogenic Monoamine Synthesis Failure
    causal_link_type: DIRECT
    description: AADC catalyzes monoamine neurotransmitter synthesis from aromatic amino acid precursors.
- name: Biogenic Monoamine Synthesis Failure
  description: >-
    Loss of AADC activity decreases synthesis of dopamine, serotonin,
    norepinephrine, and epinephrine, producing central and peripheral monoamine
    deficiency.
  biological_processes:
  - preferred_term: dopamine biosynthetic process
    term:
      id: GO:0042416
      label: dopamine biosynthetic process
    modifier: DECREASED
  - preferred_term: serotonin biosynthetic process
    term:
      id: GO:0042427
      label: serotonin biosynthetic process
    modifier: DECREASED
  - preferred_term: norepinephrine biosynthetic process
    term:
      id: GO:0042421
      label: norepinephrine biosynthetic process
    modifier: DECREASED
  chemical_entities:
  - preferred_term: dopamine
    modifier: DECREASED
    term:
      id: CHEBI:18243
      label: dopamine
  - preferred_term: serotonin
    modifier: DECREASED
    term:
      id: CHEBI:28790
      label: serotonin
  - preferred_term: norepinephrine / noradrenaline
    modifier: DECREASED
    term:
      id: CHEBI:33569
      label: noradrenaline
  - preferred_term: epinephrine / adrenaline
    modifier: DECREASED
    term:
      id: CHEBI:28918
      label: (R)-adrenaline
  evidence:
  - reference: ORPHA:35708
    reference_title: "Aromatic L-amino acid decarboxylase deficiency"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "impaired synthesis of dopamine, noradrenaline, adrenaline and serotonin."
    explanation: Orphanet definition states the affected monoamine synthesis pathways.
  - reference: PMID:28100251
    reference_title: "Consensus guideline for the diagnosis and treatment of aromatic l-amino acid decarboxylase (AADC) deficiency."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "leads to a severe combined deficiency of serotonin, dopamine, norepinephrine and epinephrine."
    explanation: Consensus guideline supports combined monoamine deficiency.
  - reference: PMID:19172410
    reference_title: "Aromatic L-amino acid decarboxylase deficiency: clinical features, drug therapy and follow-up."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "resulting in generalized combined deficiency of serotonin, dopamine and catecholamines."
    explanation: Clinical cohort describes generalized biogenic amine deficiency.
  downstream:
  - target: CSF Neurotransmitter Metabolite Signature
    causal_link_type: DIRECT
    description: Monoamine synthesis failure lowers downstream CSF metabolites and raises precursors.
  - target: Motor Circuit Dysfunction
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - dopamine deficiency in basal-ganglia motor circuits
    description: Dopamine deficiency disrupts basal-ganglia motor function.
  - target: Autonomic Dysfunction
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - peripheral and central catecholamine-serotonin deficiency
    description: Peripheral and central monoamine deficiency contributes to autonomic symptoms.
  - target: Neurodevelopmental Impairment
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - early serotonin and catecholamine deficiency during neurodevelopment
    description: Early combined monoamine deficiency disrupts neurodevelopment.
- name: CSF Neurotransmitter Metabolite Signature
  description: >-
    AADC deficiency produces a diagnostic CSF neurotransmitter pattern with low
    homovanillic acid and 5-hydroxyindoleacetic acid and elevated
    3-ortho-methyldopa.
  evidence:
  - reference: PMID:19172410
    reference_title: "Aromatic L-amino acid decarboxylase deficiency: clinical features, drug therapy and follow-up."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "In CSF all patients revealed the pattern typical of AADC with decreased concentrations of homovanillic and 5-hydroxyindoleacetic acid and elevated concentration of 3-ortho-methyldopa."
    explanation: Cohort data support the characteristic CSF metabolite pattern.
  - reference: PMID:1357595
    reference_title: "Aromatic L-amino acid decarboxylase deficiency: clinical features, diagnosis, and treatment of a new inborn error of neurotransmitter amine synthesis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Concentrations of L-dopa, 3-methoxytyrosine, and 5-hydroxytryptophan were elevated in CSF, plasma, and urine."
    explanation: Original report supports precursor accumulation caused by AADC deficiency.
  chemical_entities:
  - preferred_term: homovanillic acid
    modifier: DECREASED
    term:
      id: CHEBI:545959
      label: homovanillic acid
  - preferred_term: 5-hydroxyindoleacetic acid
    modifier: DECREASED
    term:
      id: CHEBI:27823
      label: (5-hydroxyindol-3-yl)acetic acid
  - preferred_term: 3-O-methyldopa
    modifier: INCREASED
    term:
      id: CHEBI:82913
      label: 3-O-methyldopa
  downstream:
  - target: Decreased CSF homovanillic acid concentration
    causal_link_type: DIRECT
    description: Reduced dopamine metabolism lowers CSF homovanillic acid.
  - target: Decreased CSF 5-hydroxyindolacetic acid concentration
    causal_link_type: DIRECT
    description: Reduced serotonin metabolism lowers CSF 5-hydroxyindoleacetic acid.
  - target: Increased circulating prolactin concentration
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - central dopamine deficiency
    description: Dopamine deficiency can disinhibit prolactin secretion.
- name: Motor Circuit Dysfunction
  description: >-
    Deficient dopamine synthesis in basal-ganglia motor circuits produces
    hypotonia, hypokinesia, dystonia, oculogyric crises, dyskinesia, and delayed
    motor development.
  evidence:
  - reference: PMID:28100251
    reference_title: "Consensus guideline for the diagnosis and treatment of aromatic l-amino acid decarboxylase (AADC) deficiency."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "key clinical symptoms are hypotonia, movement disorders (oculogyric crisis, dystonia, and hypokinesia), developmental delay, and autonomic symptoms."
    explanation: Consensus guideline links the biochemical disorder to core motor symptoms.
  - reference: PMID:30689738
    reference_title: "Gene therapy improves motor and mental function of aromatic l-amino acid decarboxylase deficiency."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "a decrease in catecholamines and serotonin levels in the brain leads to developmental delay and movement disorders."
    explanation: Gene-therapy study background links monoamine deficiency to motor and developmental manifestations.
  downstream:
  - target: Hypotonia
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - dopamine-dependent motor control disruption
  - target: Oculogyric crisis
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - basal-ganglia dopamine deficiency
  - target: Dystonia
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - basal-ganglia dopamine deficiency
  - target: Hypokinesia
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - basal-ganglia dopamine deficiency
  - target: Dyskinesia
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - basal-ganglia motor circuit dysfunction
  - target: Poor head control
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - axial hypotonia
  - target: Motor delay
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - early motor circuit dysfunction
  - target: Ptosis
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    description: AADC deficiency commonly includes ocular motor manifestations including ptosis.
    evidence:
    - reference: PMID:36268467
      reference_title: "Clinical Features in Aromatic L-Amino Acid Decarboxylase (AADC) Deficiency: A Systematic Review."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Oculogyric crises were seen in 67% of patients while hypokinesia in 42% and ptosis in 26%."
      explanation: Systematic review quantifies ptosis among neurologic/ocular motor manifestations.
  - target: Reduced tendon reflexes
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - abnormal motor tone and reflex control
    description: Motor-system dysfunction can include reduced tendon reflexes.
    evidence:
    - reference: ORPHA:35708
      reference_title: "Aromatic L-amino acid decarboxylase deficiency"
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "HP:0001315 | Reduced tendon reflexes | Occasional (29-5%)"
      explanation: Orphanet lists reduced tendon reflexes among AADC deficiency neurologic manifestations.
  - target: Limb hypertonia
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - abnormal motor tone regulation
    description: Basal-ganglia and motor-circuit dysfunction can manifest as limb hypertonia.
    evidence:
    - reference: ORPHA:35708
      reference_title: "Aromatic L-amino acid decarboxylase deficiency"
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "HP:0002509 | Limb hypertonia | Occasional (29-5%)"
      explanation: Orphanet lists limb hypertonia as an occasional neurologic manifestation.
  - target: Babinski sign
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - central motor pathway dysfunction
    description: Central motor dysfunction can manifest as Babinski sign.
    evidence:
    - reference: ORPHA:35708
      reference_title: "Aromatic L-amino acid decarboxylase deficiency"
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "HP:0003487 | Babinski sign | Occasional (29-5%)"
      explanation: Orphanet lists Babinski sign as an occasional neurologic manifestation.
  - target: Tremor
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - basal-ganglia motor circuit dysfunction
    description: Movement-disorder circuitry can rarely manifest as tremor.
    evidence:
    - reference: ORPHA:35708
      reference_title: "Aromatic L-amino acid decarboxylase deficiency"
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "HP:0001337 | Tremor | Very rare (<4-1%)"
      explanation: Orphanet lists tremor as a very rare movement manifestation.
  - target: Joint contracture
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - chronic abnormal motor tone and limited mobility
    description: Chronic neuromotor impairment can contribute to joint contractures.
    evidence:
    - reference: ORPHA:35708
      reference_title: "Aromatic L-amino acid decarboxylase deficiency"
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "HP:0034392 | Joint contracture | Very rare (<4-1%)"
      explanation: Orphanet lists joint contracture as a very rare musculoskeletal manifestation.
- name: Autonomic Dysfunction
  description: >-
    Combined catecholamine and serotonin deficiency contributes to autonomic and
    extraneurological symptoms including hyperhidrosis, nasal congestion,
    hypersalivation/drooling, sleep disturbance, hypotension, and miosis.
  evidence:
  - reference: PMID:19172410
    reference_title: "Aromatic L-amino acid decarboxylase deficiency: clinical features, drug therapy and follow-up."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "All patients presented distinct extraneurological symptoms, such as hypersalivation, hyperhidrosis, nasal congestion, sleep disturbances and hypoglycaemia."
    explanation: Clinical cohort supports autonomic and extraneurologic manifestations.
  - reference: PMID:32409695
    reference_title: "The genetic and clinical characteristics of aromatic L-amino acid decarboxylase deficiency in mainland China."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "autonomic symptoms such as excessive sweating, nasal congestion and profuse nasal, and oropharyngeal secretions, were common in our patients."
    explanation: Mainland China cohort supports frequent autonomic symptoms.
  downstream:
  - target: Hyperhidrosis
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - autonomic monoamine deficiency
  - target: Nasal congestion
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - autonomic monoamine deficiency
  - target: Drooling
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - hypersalivation from autonomic dysfunction
  - target: Sleep abnormality
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - serotonin and catecholamine deficiency
  - target: Hypotension
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - catecholamine deficiency
  - target: Miosis
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - autonomic dysfunction
  - target: Hypoglycemia
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - autonomic and catecholamine deficiency
  - target: Constipation
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - autonomic gastrointestinal dysmotility
    description: Dysautonomia and neuromotor dysfunction can manifest as constipation.
    evidence:
    - reference: ORPHA:35708
      reference_title: "Aromatic L-amino acid decarboxylase deficiency"
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "HP:0002019 | Constipation | Occasional (29-5%)"
      explanation: Orphanet lists constipation as an occasional gastrointestinal manifestation.
  - target: Diarrhea
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - autonomic gastrointestinal dysmotility
    description: Gastrointestinal autonomic dysfunction can rarely manifest as diarrhea.
    evidence:
    - reference: ORPHA:35708
      reference_title: "Aromatic L-amino acid decarboxylase deficiency"
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "HP:0002014 | Diarrhea | Very rare (<4-1%)"
      explanation: Orphanet lists diarrhea as a very rare gastrointestinal manifestation.
  - target: Gastroesophageal reflux
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - gastrointestinal dysmotility
    - hypotonia and impaired feeding coordination
    description: Autonomic and neuromotor gastrointestinal dysfunction can contribute to reflux.
    evidence:
    - reference: ORPHA:35708
      reference_title: "Aromatic L-amino acid decarboxylase deficiency"
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "HP:0002020 | Gastroesophageal reflux | Frequent (79-30%)"
      explanation: Orphanet lists gastroesophageal reflux as a frequent gastrointestinal manifestation.
- name: Neurodevelopmental Impairment
  description: >-
    Early combined monoamine deficiency impairs developmental acquisition and is
    associated with global developmental delay, intellectual disability,
    seizures, feeding difficulties, and failure to thrive.
  evidence:
  - reference: PMID:36268467
    reference_title: "Clinical Features in Aromatic L-Amino Acid Decarboxylase (AADC) Deficiency: A Systematic Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Hypotonia and developmental delay are cardinal signs, reported as present in 73.9% and 72% of cases, respectively."
    explanation: Systematic review supports common developmental delay and hypotonia.
  - reference: PMID:30689738
    reference_title: "Gene therapy improves motor and mental function of aromatic l-amino acid decarboxylase deficiency."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "In patients with aromatic l-amino acid decarboxylase (AADC) deficiency, a decrease in catecholamines and serotonin levels in the brain leads to developmental delay and movement disorders."
    explanation: Gene-therapy study background links brain monoamine deficiency to developmental delay.
  downstream:
  - target: Global developmental delay
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - early monoamine neurotransmitter deficiency
  - target: Intellectual disability
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - early monoamine neurotransmitter deficiency
  - target: Seizure
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - neurotransmitter imbalance
  - target: Feeding difficulties
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - hypotonia and neuromotor dysfunction
  - target: Failure to thrive
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - feeding difficulties and neurometabolic disease
  - target: Dysarthria
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - motor and neurodevelopmental impairment
  - target: Atypical behavior
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - early monoamine neurotransmitter deficiency
    description: Early serotonin and catecholamine deficiency is associated with behavioral disorders.
    evidence:
    - reference: PMID:36268467
      reference_title: "Clinical Features in Aromatic L-Amino Acid Decarboxylase (AADC) Deficiency: A Systematic Review."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "With 37% and 30% of patients reported being affected by sleep and behavioural disorders"
      explanation: Systematic review supports behavioral manifestations downstream of the neurometabolic disorder.
  - target: Autistic behavior
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - early monoamine neurotransmitter deficiency
    description: Neurodevelopmental monoamine deficiency can include autistic behavior.
    evidence:
    - reference: ORPHA:35708
      reference_title: "Aromatic L-amino acid decarboxylase deficiency"
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "HP:0000729 | Autistic behavior | Occasional (29-5%)"
      explanation: Orphanet lists autistic behavior as an occasional behavioral manifestation.
  - target: Irritability
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - serotonin and catecholamine deficiency
    description: Non-motor neurobehavioral manifestations include irritability.
    evidence:
    - reference: ORPHA:35708
      reference_title: "Aromatic L-amino acid decarboxylase deficiency"
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "HP:0000737 | Irritability | Frequent (79-30%)"
      explanation: Orphanet lists irritability as a frequent behavioral manifestation.
  - target: EEG abnormality
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - neurotransmitter imbalance
    description: Neurotransmitter imbalance and seizures can be accompanied by EEG abnormalities.
    evidence:
    - reference: ORPHA:35708
      reference_title: "Aromatic L-amino acid decarboxylase deficiency"
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "HP:0002353 | EEG abnormality | Occasional (29-5%)"
      explanation: Orphanet lists EEG abnormality as an occasional neurologic manifestation.
  - target: Dysphagia
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - hypotonia and impaired feeding coordination
    description: Neurodevelopmental and motor impairment can contribute to swallowing difficulty.
    evidence:
    - reference: ORPHA:35708
      reference_title: "Aromatic L-amino acid decarboxylase deficiency"
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "HP:0002015 | Dysphagia | Occasional (29-5%)"
      explanation: Orphanet lists dysphagia as an occasional growth and feeding manifestation.
  - target: Short stature
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - chronic feeding difficulty and neurometabolic disease
    description: Chronic feeding difficulty and neurometabolic disease can contribute to impaired growth.
    evidence:
    - reference: ORPHA:35708
      reference_title: "Aromatic L-amino acid decarboxylase deficiency"
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "HP:0004322 | Short stature | Occasional (29-5%)"
      explanation: Orphanet lists short stature as an occasional growth manifestation.
phenotypes:
- category: Ophthalmologic
  name: Ptosis
  frequency: OCCASIONAL
  phenotype_term:
    preferred_term: Ptosis
    term:
      id: HP:0000508
      label: Ptosis
  evidence:
  - reference: ORPHA:35708
    reference_title: "Aromatic L-amino acid decarboxylase deficiency"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0000508 | Ptosis | Occasional (29-5%)"
    explanation: Orphanet provides the phenotype association and frequency band.
  - reference: PMID:36268467
    reference_title: "Clinical Features in Aromatic L-Amino Acid Decarboxylase (AADC) Deficiency: A Systematic Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Oculogyric crises were seen in 67% of patients while hypokinesia in 42% and ptosis in 26%."
    explanation: Systematic review quantifies ptosis in the occasional range.
- category: Ophthalmologic
  name: Miosis
  frequency: OCCASIONAL
  phenotype_term:
    preferred_term: Miosis
    term:
      id: HP:0000616
      label: Miosis
  evidence:
  - reference: ORPHA:35708
    reference_title: "Aromatic L-amino acid decarboxylase deficiency"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0000616 | Miosis | Occasional (29-5%)"
    explanation: Orphanet provides the phenotype association and frequency band.
- category: Behavioral
  name: Atypical behavior
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Atypical behavior
    term:
      id: HP:0000708
      label: Atypical behavior
  evidence:
  - reference: ORPHA:35708
    reference_title: "Aromatic L-amino acid decarboxylase deficiency"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0000708 | Atypical behavior | Frequent (79-30%)"
    explanation: Orphanet provides the phenotype association and frequency band.
  - reference: PMID:36268467
    reference_title: "Clinical Features in Aromatic L-Amino Acid Decarboxylase (AADC) Deficiency: A Systematic Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "With 37% and 30% of patients reported being affected by sleep and behavioural disorders"
    explanation: Systematic review supports frequent behavioral manifestations.
- category: Behavioral
  name: Autistic behavior
  frequency: OCCASIONAL
  phenotype_term:
    preferred_term: Autistic behavior
    term:
      id: HP:0000729
      label: Autistic behavior
  evidence:
  - reference: ORPHA:35708
    reference_title: "Aromatic L-amino acid decarboxylase deficiency"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0000729 | Autistic behavior | Occasional (29-5%)"
    explanation: Orphanet provides the phenotype association and frequency band.
- category: Behavioral
  name: Irritability
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Irritability
    term:
      id: HP:0000737
      label: Irritability
  evidence:
  - reference: ORPHA:35708
    reference_title: "Aromatic L-amino acid decarboxylase deficiency"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0000737 | Irritability | Frequent (79-30%)"
    explanation: Orphanet provides the phenotype association and frequency band.
- category: Biochemical
  name: Increased circulating prolactin concentration
  frequency: OCCASIONAL
  phenotype_term:
    preferred_term: Increased circulating prolactin concentration
    term:
      id: HP:0000870
      label: Increased circulating prolactin concentration
  evidence:
  - reference: ORPHA:35708
    reference_title: "Aromatic L-amino acid decarboxylase deficiency"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0000870 | Increased circulating prolactin concentration | Occasional (29-5%)"
    explanation: Orphanet provides the phenotype association and frequency band.
- category: Autonomic
  name: Hyperhidrosis
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Hyperhidrosis
    term:
      id: HP:0000975
      label: Hyperhidrosis
  evidence:
  - reference: ORPHA:35708
    reference_title: "Aromatic L-amino acid decarboxylase deficiency"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0000975 | Hyperhidrosis | Frequent (79-30%)"
    explanation: Orphanet provides the phenotype association and frequency band.
  - reference: PMID:19172410
    reference_title: "Aromatic L-amino acid decarboxylase deficiency: clinical features, drug therapy and follow-up."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "All patients presented distinct extraneurological symptoms, such as hypersalivation, hyperhidrosis, nasal congestion, sleep disturbances and hypoglycaemia."
    explanation: Clinical cohort supports hyperhidrosis as an AADC deficiency manifestation.
- category: Neurologic
  name: Intellectual disability
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Intellectual disability
    term:
      id: HP:0001249
      label: Intellectual disability
  evidence:
  - reference: ORPHA:35708
    reference_title: "Aromatic L-amino acid decarboxylase deficiency"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0001249 | Intellectual disability | Frequent (79-30%)"
    explanation: Orphanet provides the phenotype association and frequency band.
- category: Neurologic
  name: Seizure
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Seizure
    term:
      id: HP:0001250
      label: Seizure
  evidence:
  - reference: ORPHA:35708
    reference_title: "Aromatic L-amino acid decarboxylase deficiency"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0001250 | Seizure | Frequent (79-30%)"
    explanation: Orphanet provides the phenotype association and frequency band.
  - reference: PMID:19172410
    reference_title: "Aromatic L-amino acid decarboxylase deficiency: clinical features, drug therapy and follow-up."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Three patients had single seizures."
    explanation: Clinical cohort documents seizures in AADC deficiency.
- category: Neurologic
  name: Hypotonia
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Hypotonia
    term:
      id: HP:0001252
      label: Hypotonia
  evidence:
  - reference: ORPHA:35708
    reference_title: "Aromatic L-amino acid decarboxylase deficiency"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0001252 | Hypotonia | Frequent (79-30%)"
    explanation: Orphanet provides the phenotype association and frequency band.
  - reference: PMID:36268467
    reference_title: "Clinical Features in Aromatic L-Amino Acid Decarboxylase (AADC) Deficiency: A Systematic Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Hypotonia and developmental delay are cardinal signs, reported as present in 73.9% and 72% of cases, respectively."
    explanation: Systematic review quantifies hypotonia in the frequent range.
- category: Neurologic
  name: Dysarthria
  frequency: OCCASIONAL
  phenotype_term:
    preferred_term: Dysarthria
    term:
      id: HP:0001260
      label: Dysarthria
  evidence:
  - reference: ORPHA:35708
    reference_title: "Aromatic L-amino acid decarboxylase deficiency"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0001260 | Dysarthria | Occasional (29-5%)"
    explanation: Orphanet provides the phenotype association and frequency band.
- category: Neurologic
  name: Global developmental delay
  frequency: VERY_FREQUENT
  phenotype_term:
    preferred_term: Global developmental delay
    term:
      id: HP:0001263
      label: Global developmental delay
  evidence:
  - reference: ORPHA:35708
    reference_title: "Aromatic L-amino acid decarboxylase deficiency"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0001263 | Global developmental delay | Very frequent (99-80%)"
    explanation: Orphanet provides the phenotype association and frequency band.
  - reference: PMID:36268467
    reference_title: "Clinical Features in Aromatic L-Amino Acid Decarboxylase (AADC) Deficiency: A Systematic Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Hypotonia and developmental delay are cardinal signs, reported as present in 73.9% and 72% of cases, respectively."
    explanation: Systematic review supports developmental delay as a cardinal sign.
- category: Neurologic
  name: Motor delay
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Motor delay
    term:
      id: HP:0001270
      label: Motor delay
  evidence:
  - reference: ORPHA:35708
    reference_title: "Aromatic L-amino acid decarboxylase deficiency"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0001270 | Motor delay | Frequent (79-30%)"
    explanation: Orphanet provides the phenotype association and frequency band.
- category: Neurologic
  name: Reduced tendon reflexes
  frequency: OCCASIONAL
  phenotype_term:
    preferred_term: Reduced tendon reflexes
    term:
      id: HP:0001315
      label: Reduced tendon reflexes
  evidence:
  - reference: ORPHA:35708
    reference_title: "Aromatic L-amino acid decarboxylase deficiency"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0001315 | Reduced tendon reflexes | Occasional (29-5%)"
    explanation: Orphanet provides the phenotype association and frequency band.
- category: Neurologic
  name: Dystonia
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Dystonia
    term:
      id: HP:0001332
      label: Dystonia
  evidence:
  - reference: ORPHA:35708
    reference_title: "Aromatic L-amino acid decarboxylase deficiency"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0001332 | Dystonia | Frequent (79-30%)"
    explanation: Orphanet provides the phenotype association and frequency band.
  - reference: PMID:28100251
    reference_title: "Consensus guideline for the diagnosis and treatment of aromatic l-amino acid decarboxylase (AADC) deficiency."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "movement disorders (oculogyric crisis, dystonia, and hypokinesia)"
    explanation: Consensus guideline lists dystonia as a key movement disorder.
- category: Neurologic
  name: Tremor
  frequency: VERY_RARE
  phenotype_term:
    preferred_term: Tremor
    term:
      id: HP:0001337
      label: Tremor
  evidence:
  - reference: ORPHA:35708
    reference_title: "Aromatic L-amino acid decarboxylase deficiency"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0001337 | Tremor | Very rare (<4-1%)"
    explanation: Orphanet provides the phenotype association and frequency band.
- category: Growth and feeding
  name: Failure to thrive
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Failure to thrive
    term:
      id: HP:0001508
      label: Failure to thrive
  evidence:
  - reference: ORPHA:35708
    reference_title: "Aromatic L-amino acid decarboxylase deficiency"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0001508 | Failure to thrive | Frequent (79-30%)"
    explanation: Orphanet provides the phenotype association and frequency band.
- category: Autonomic
  name: Nasal congestion
  frequency: OCCASIONAL
  phenotype_term:
    preferred_term: Nasal congestion
    term:
      id: HP:0001742
      label: Nasal congestion
  evidence:
  - reference: ORPHA:35708
    reference_title: "Aromatic L-amino acid decarboxylase deficiency"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0001742 | Nasal congestion | Occasional (29-5%)"
    explanation: Orphanet provides the phenotype association and frequency band.
  - reference: PMID:32409695
    reference_title: "The genetic and clinical characteristics of aromatic L-amino acid decarboxylase deficiency in mainland China."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "autonomic symptoms such as excessive sweating, nasal congestion and profuse nasal, and oropharyngeal secretions, were common in our patients."
    explanation: Mainland China cohort supports nasal congestion as an autonomic manifestation.
- category: Autonomic
  name: Hypoglycemia
  frequency: OCCASIONAL
  phenotype_term:
    preferred_term: Hypoglycemia
    term:
      id: HP:0001943
      label: Hypoglycemia
  evidence:
  - reference: ORPHA:35708
    reference_title: "Aromatic L-amino acid decarboxylase deficiency"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0001943 | Hypoglycemia | Occasional (29-5%)"
    explanation: Orphanet provides the phenotype association and frequency band.
  - reference: PMID:19172410
    reference_title: "Aromatic L-amino acid decarboxylase deficiency: clinical features, drug therapy and follow-up."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "All patients presented distinct extraneurological symptoms, such as hypersalivation, hyperhidrosis, nasal congestion, sleep disturbances and hypoglycaemia."
    explanation: Clinical cohort documents hypoglycemia among extraneurological symptoms.
- category: Gastrointestinal
  name: Diarrhea
  frequency: VERY_RARE
  phenotype_term:
    preferred_term: Diarrhea
    term:
      id: HP:0002014
      label: Diarrhea
  evidence:
  - reference: ORPHA:35708
    reference_title: "Aromatic L-amino acid decarboxylase deficiency"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0002014 | Diarrhea | Very rare (<4-1%)"
    explanation: Orphanet provides the phenotype association and frequency band.
- category: Growth and feeding
  name: Dysphagia
  frequency: OCCASIONAL
  phenotype_term:
    preferred_term: Dysphagia
    term:
      id: HP:0002015
      label: Dysphagia
  evidence:
  - reference: ORPHA:35708
    reference_title: "Aromatic L-amino acid decarboxylase deficiency"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0002015 | Dysphagia | Occasional (29-5%)"
    explanation: Orphanet provides the phenotype association and frequency band.
- category: Gastrointestinal
  name: Constipation
  frequency: OCCASIONAL
  phenotype_term:
    preferred_term: Constipation
    term:
      id: HP:0002019
      label: Constipation
  evidence:
  - reference: ORPHA:35708
    reference_title: "Aromatic L-amino acid decarboxylase deficiency"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0002019 | Constipation | Occasional (29-5%)"
    explanation: Orphanet provides the phenotype association and frequency band.
- category: Gastrointestinal
  name: Gastroesophageal reflux
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Gastroesophageal reflux
    term:
      id: HP:0002020
      label: Gastroesophageal reflux
  evidence:
  - reference: ORPHA:35708
    reference_title: "Aromatic L-amino acid decarboxylase deficiency"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0002020 | Gastroesophageal reflux | Frequent (79-30%)"
    explanation: Orphanet provides the phenotype association and frequency band.
- category: Autonomic
  name: Drooling
  frequency: OCCASIONAL
  phenotype_term:
    preferred_term: Drooling
    term:
      id: HP:0002307
      label: Drooling
  evidence:
  - reference: ORPHA:35708
    reference_title: "Aromatic L-amino acid decarboxylase deficiency"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0002307 | Drooling | Occasional (29-5%)"
    explanation: Orphanet provides the phenotype association and frequency band.
- category: Neurologic
  name: EEG abnormality
  frequency: OCCASIONAL
  phenotype_term:
    preferred_term: EEG abnormality
    term:
      id: HP:0002353
      label: EEG abnormality
  evidence:
  - reference: ORPHA:35708
    reference_title: "Aromatic L-amino acid decarboxylase deficiency"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0002353 | EEG abnormality | Occasional (29-5%)"
    explanation: Orphanet provides the phenotype association and frequency band.
- category: Neurologic
  name: Sleep abnormality
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Sleep abnormality
    term:
      id: HP:0002360
      label: Sleep disturbance
  evidence:
  - reference: ORPHA:35708
    reference_title: "Aromatic L-amino acid decarboxylase deficiency"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0002360 | Sleep abnormality | Frequent (79-30%)"
    explanation: Orphanet provides the phenotype association and frequency band.
  - reference: PMID:36268467
    reference_title: "Clinical Features in Aromatic L-Amino Acid Decarboxylase (AADC) Deficiency: A Systematic Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "With 37% and 30% of patients reported being affected by sleep and behavioural disorders"
    explanation: Systematic review supports sleep abnormality in the frequent range.
- category: Neurologic
  name: Hypokinesia
  frequency: OCCASIONAL
  phenotype_term:
    preferred_term: Hypokinesia
    term:
      id: HP:0002375
      label: Hypokinesia
  evidence:
  - reference: ORPHA:35708
    reference_title: "Aromatic L-amino acid decarboxylase deficiency"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0002375 | Hypokinesia | Occasional (29-5%)"
    explanation: Orphanet provides the phenotype association and frequency band.
- category: Neurologic
  name: Poor head control
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Poor head control
    term:
      id: HP:0002421
      label: Poor head control
  evidence:
  - reference: ORPHA:35708
    reference_title: "Aromatic L-amino acid decarboxylase deficiency"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0002421 | Poor head control | Frequent (79-30%)"
    explanation: Orphanet provides the phenotype association and frequency band.
- category: Neurologic
  name: Limb hypertonia
  frequency: OCCASIONAL
  phenotype_term:
    preferred_term: Limb hypertonia
    term:
      id: HP:0002509
      label: Limb hypertonia
  evidence:
  - reference: ORPHA:35708
    reference_title: "Aromatic L-amino acid decarboxylase deficiency"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0002509 | Limb hypertonia | Occasional (29-5%)"
    explanation: Orphanet provides the phenotype association and frequency band.
- category: Autonomic
  name: Hypotension
  frequency: OCCASIONAL
  phenotype_term:
    preferred_term: Hypotension
    term:
      id: HP:0002615
      label: Hypotension
  evidence:
  - reference: ORPHA:35708
    reference_title: "Aromatic L-amino acid decarboxylase deficiency"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0002615 | Hypotension | Occasional (29-5%)"
    explanation: Orphanet provides the phenotype association and frequency band.
- category: Neurologic
  name: Babinski sign
  frequency: OCCASIONAL
  phenotype_term:
    preferred_term: Babinski sign
    term:
      id: HP:0003487
      label: Babinski sign
  evidence:
  - reference: ORPHA:35708
    reference_title: "Aromatic L-amino acid decarboxylase deficiency"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0003487 | Babinski sign | Occasional (29-5%)"
    explanation: Orphanet provides the phenotype association and frequency band.
- category: Biochemical
  name: Decreased CSF homovanillic acid concentration
  frequency: VERY_FREQUENT
  phenotype_term:
    preferred_term: Decreased CSF homovanillic acid concentration
    term:
      id: HP:0003785
      label: Decreased CSF homovanillic acid concentration
  evidence:
  - reference: ORPHA:35708
    reference_title: "Aromatic L-amino acid decarboxylase deficiency"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0003785 | Decreased CSF homovanillic acid concentration | Very frequent (99-80%)"
    explanation: Orphanet provides the phenotype association and frequency band.
  - reference: PMID:19172410
    reference_title: "Aromatic L-amino acid decarboxylase deficiency: clinical features, drug therapy and follow-up."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "In CSF all patients revealed the pattern typical of AADC with decreased concentrations of homovanillic and 5-hydroxyindoleacetic acid and elevated concentration of 3-ortho-methyldopa."
    explanation: Clinical cohort supports decreased CSF homovanillic acid.
- category: Growth and feeding
  name: Short stature
  frequency: OCCASIONAL
  phenotype_term:
    preferred_term: Short stature
    term:
      id: HP:0004322
      label: Short stature
  evidence:
  - reference: ORPHA:35708
    reference_title: "Aromatic L-amino acid decarboxylase deficiency"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0004322 | Short stature | Occasional (29-5%)"
    explanation: Orphanet provides the phenotype association and frequency band.
- category: Neurologic
  name: Oculogyric crisis
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Oculogyric crisis
    term:
      id: HP:0010553
      label: Oculogyric crisis
  evidence:
  - reference: ORPHA:35708
    reference_title: "Aromatic L-amino acid decarboxylase deficiency"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0010553 | Oculogyric crisis | Frequent (79-30%)"
    explanation: Orphanet provides the phenotype association and frequency band.
  - reference: PMID:36268467
    reference_title: "Clinical Features in Aromatic L-Amino Acid Decarboxylase (AADC) Deficiency: A Systematic Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Oculogyric crises were seen in 67% of patients while hypokinesia in 42% and ptosis in 26%."
    explanation: Systematic review quantifies oculogyric crises in the frequent range.
- category: Growth and feeding
  name: Feeding difficulties
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Feeding difficulties
    term:
      id: HP:0011968
      label: Feeding difficulties
  evidence:
  - reference: ORPHA:35708
    reference_title: "Aromatic L-amino acid decarboxylase deficiency"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0011968 | Feeding difficulties | Frequent (79-30%)"
    explanation: Orphanet provides the phenotype association and frequency band.
- category: Biochemical
  name: Decreased CSF 5-hydroxyindolacetic acid concentration
  frequency: VERY_FREQUENT
  phenotype_term:
    preferred_term: Decreased CSF 5-hydroxyindolacetic acid concentration
    term:
      id: HP:0025455
      label: Decreased CSF 5-hydroxyindolacetic acid concentration
  evidence:
  - reference: ORPHA:35708
    reference_title: "Aromatic L-amino acid decarboxylase deficiency"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0025455 | Decreased CSF 5-hydroxyindolacetic acid concentration | Very frequent (99-80%)"
    explanation: Orphanet provides the phenotype association and frequency band.
  - reference: PMID:19172410
    reference_title: "Aromatic L-amino acid decarboxylase deficiency: clinical features, drug therapy and follow-up."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "In CSF all patients revealed the pattern typical of AADC with decreased concentrations of homovanillic and 5-hydroxyindoleacetic acid and elevated concentration of 3-ortho-methyldopa."
    explanation: Clinical cohort supports decreased CSF 5-hydroxyindoleacetic acid.
- category: Musculoskeletal
  name: Joint contracture
  frequency: VERY_RARE
  phenotype_term:
    preferred_term: Joint contracture
    term:
      id: HP:0034392
      label: Joint contracture
  evidence:
  - reference: ORPHA:35708
    reference_title: "Aromatic L-amino acid decarboxylase deficiency"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0034392 | Joint contracture | Very rare (<4-1%)"
    explanation: Orphanet provides the phenotype association and frequency band.
- category: Neurologic
  name: Dyskinesia
  frequency: OCCASIONAL
  phenotype_term:
    preferred_term: Dyskinesia
    term:
      id: HP:0100660
      label: Dyskinesia
  evidence:
  - reference: ORPHA:35708
    reference_title: "Aromatic L-amino acid decarboxylase deficiency"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0100660 | Dyskinesia | Occasional (29-5%)"
    explanation: Orphanet provides the phenotype association and frequency band.
biochemical:
- name: Low CSF homovanillic acid
  presence: DECREASED
  biomarker_term:
    preferred_term: homovanillic acid
    term:
      id: CHEBI:545959
      label: homovanillic acid
  notes: >-
    Low CSF homovanillic acid is a diagnostic readout of reduced dopamine
    synthesis and downstream dopamine metabolism.
  readouts:
  - target: CSF Neurotransmitter Metabolite Signature
    relationship: READOUT_OF
    direction: NEGATIVE
    endpoint_context: DIAGNOSTIC
    interpretation: Decreased CSF HVA reports the dopamine-metabolite arm of the AADC deficiency CSF signature.
  evidence:
  - reference: PMID:19172410
    reference_title: "Aromatic L-amino acid decarboxylase deficiency: clinical features, drug therapy and follow-up."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "In CSF all patients revealed the pattern typical of AADC with decreased concentrations of homovanillic and 5-hydroxyindoleacetic acid and elevated concentration of 3-ortho-methyldopa."
    explanation: Clinical cohort supports decreased CSF homovanillic acid in the diagnostic profile.
- name: Low CSF 5-hydroxyindoleacetic acid
  presence: DECREASED
  biomarker_term:
    preferred_term: 5-hydroxyindoleacetic acid
    term:
      id: CHEBI:27823
      label: (5-hydroxyindol-3-yl)acetic acid
  notes: >-
    Low CSF 5-hydroxyindoleacetic acid is a diagnostic readout of reduced
    serotonin synthesis and serotonin turnover.
  readouts:
  - target: CSF Neurotransmitter Metabolite Signature
    relationship: READOUT_OF
    direction: NEGATIVE
    endpoint_context: DIAGNOSTIC
    interpretation: Decreased CSF 5-HIAA reports the serotonin-metabolite arm of the AADC deficiency CSF signature.
  evidence:
  - reference: PMID:19172410
    reference_title: "Aromatic L-amino acid decarboxylase deficiency: clinical features, drug therapy and follow-up."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "In CSF all patients revealed the pattern typical of AADC with decreased concentrations of homovanillic and 5-hydroxyindoleacetic acid and elevated concentration of 3-ortho-methyldopa."
    explanation: Clinical cohort supports decreased CSF 5-hydroxyindoleacetic acid in the diagnostic profile.
- name: Elevated CSF 3-O-methyldopa
  presence: INCREASED
  biomarker_term:
    preferred_term: 3-O-methyldopa
    term:
      id: CHEBI:82913
      label: 3-O-methyldopa
  notes: >-
    Elevated 3-O-methyldopa reflects accumulation and alternative metabolism of
    aromatic amino acid precursors when AADC activity is deficient.
  readouts:
  - target: CSF Neurotransmitter Metabolite Signature
    relationship: READOUT_OF
    direction: POSITIVE
    endpoint_context: DIAGNOSTIC
    interpretation: Elevated 3-OMD reports precursor shunting in the AADC deficiency CSF signature.
  evidence:
  - reference: PMID:19172410
    reference_title: "Aromatic L-amino acid decarboxylase deficiency: clinical features, drug therapy and follow-up."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "In CSF all patients revealed the pattern typical of AADC with decreased concentrations of homovanillic and 5-hydroxyindoleacetic acid and elevated concentration of 3-ortho-methyldopa."
    explanation: Clinical cohort supports elevated 3-ortho-methyldopa in the diagnostic CSF profile.
- name: Reduced plasma AADC activity
  presence: DECREASED
  notes: Plasma AADC activity is reduced or absent and confirms the enzymatic defect.
  readouts:
  - target: DDC Enzymatic Deficiency
    relationship: READOUT_OF
    direction: NEGATIVE
    endpoint_context: DIAGNOSTIC
    interpretation: Reduced plasma AADC activity reports the primary DDC enzyme deficiency.
  evidence:
  - reference: PMID:19172410
    reference_title: "Aromatic L-amino acid decarboxylase deficiency: clinical features, drug therapy and follow-up."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Diagnosis was confirmed by measurement of AADC activity in plasma in all patients."
    explanation: Clinical cohort supports plasma AADC activity as an enzymatic diagnostic readout.
  - reference: PMID:1357595
    reference_title: "Aromatic L-amino acid decarboxylase deficiency: clinical features, diagnosis, and treatment of a new inborn error of neurotransmitter amine synthesis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Activity of aromatic L-amino acid decarboxylase was virtually absent in a liver biopsy sample and greatly reduced in plasma."
    explanation: Original report supports reduced AADC activity in plasma and tissue.
diagnosis:
- name: DDC molecular genetic testing
  description: >-
    Molecular genetic testing confirms pathogenic DDC variants and supports
    definitive diagnosis in a compatible clinical and biochemical setting.
  diagnosis_term:
    preferred_term: genetic testing
    term:
      id: MAXO:0000127
      label: genetic testing
  evidence:
  - reference: PMID:36268467
    reference_title: "Clinical Features in Aromatic L-Amino Acid Decarboxylase (AADC) Deficiency: A Systematic Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "molecular and/or biochemical diagnosis of AADC deficiency"
    explanation: Systematic review includes molecular diagnosis as a defining diagnostic route.
  - reference: PMID:32409695
    reference_title: "The genetic and clinical characteristics of aromatic L-amino acid decarboxylase deficiency in mainland China."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Twenty-three patients with clinical features of AADCD and DDC gene variants were recruited."
    explanation: Cohort diagnosis used clinical features with DDC variants.
- name: CSF neurotransmitter metabolite testing
  description: >-
    CSF neurotransmitter testing shows low homovanillic acid and
    5-hydroxyindoleacetic acid with elevated 3-ortho-methyldopa.
  evidence:
  - reference: PMID:19172410
    reference_title: "Aromatic L-amino acid decarboxylase deficiency: clinical features, drug therapy and follow-up."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "In CSF all patients revealed the pattern typical of AADC with decreased concentrations of homovanillic and 5-hydroxyindoleacetic acid and elevated concentration of 3-ortho-methyldopa."
    explanation: Cohort data support CSF neurotransmitter metabolite testing.
- name: Plasma AADC enzyme activity assay
  description: >-
    Plasma aromatic L-amino acid decarboxylase activity measurement can confirm
    the enzymatic deficiency.
  evidence:
  - reference: PMID:19172410
    reference_title: "Aromatic L-amino acid decarboxylase deficiency: clinical features, drug therapy and follow-up."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Diagnosis was confirmed by measurement of AADC activity in plasma in all patients."
    explanation: Clinical cohort supports plasma AADC activity measurement.
  - reference: PMID:1357595
    reference_title: "Aromatic L-amino acid decarboxylase deficiency: clinical features, diagnosis, and treatment of a new inborn error of neurotransmitter amine synthesis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Activity of aromatic L-amino acid decarboxylase was virtually absent in a liver biopsy sample and greatly reduced in plasma."
    explanation: Original case report supports enzyme activity measurement.
treatments:
- name: Eladocagene exuparvovec gene therapy
  description: >-
    Eladocagene exuparvovec delivers DDC via an adeno-associated viral vector to
    the putamen, aiming to restore dopamine synthesis and improve motor,
    developmental, and oculogyric manifestations.
  treatment_term:
    preferred_term: gene therapy
    term:
      id: MAXO:0001001
      label: gene therapy
    therapeutic_agent:
    - preferred_term: eladocagene exuparvovec
      term:
        id: NCIT:C171796
        label: Eladocagene Exuparvovec
  target_mechanisms:
  - target: DDC Enzymatic Deficiency
    treatment_effect: RESTORES
    description: Gene addition supplies the human DDC coding sequence to restore AADC activity in the putamen.
    evidence:
    - reference: PMID:30689738
      reference_title: "Gene therapy improves motor and mental function of aromatic l-amino acid decarboxylase deficiency."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "The patients received a total of 2 × 1011 vector genomes of adeno-associated virus vector harbouring DDC via bilateral intraputaminal infusions."
      explanation: Open-label clinical study describes AAV vector delivery of DDC to the putamen.
  - target: Biogenic Monoamine Synthesis Failure
    treatment_effect: RESTORES
    description: Restored putaminal DDC expression increases dopamine synthesis.
    evidence:
    - reference: PMID:30689738
      reference_title: "Gene therapy improves motor and mental function of aromatic l-amino acid decarboxylase deficiency."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "The restoration of dopamine synthesis in the putamen via gene transfer provides transformative medical benefit across all patient ages"
      explanation: Clinical study supports restoration of putaminal dopamine synthesis.
  evidence:
  - reference: PMID:30689738
    reference_title: "Gene therapy improves motor and mental function of aromatic l-amino acid decarboxylase deficiency."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "At up to 2 years after gene therapy, the motor function was remarkably improved in all patients."
    explanation: Open-label phase 1/2 study supports motor improvement after AAV-DDC gene therapy.
  - reference: PMID:30689738
    reference_title: "Gene therapy improves motor and mental function of aromatic l-amino acid decarboxylase deficiency."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Dystonia disappeared and oculogyric crisis was markedly decreased in all patients."
    explanation: Gene therapy improved key movement disorder manifestations.
  - reference: DOI:10.1001/jama.2024.28666
    reference_title: "Eladocagene Exuparvovec for Aromatic L-Amino Acid Decarboxylase Deficiency"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "US Food and Drug Administration approval of Kebilidi, eladocagene exuparvovec, for the treatment of aromatic L-amino acid decarboxylase deficiency in adult and pediatric patients."
    explanation: JAMA Insights reports FDA approval for AADC deficiency.
- name: Pyridoxine pharmacotherapy
  description: >-
    Pyridoxine or pyridoxal phosphate is used as cofactor-directed symptomatic
    therapy, often in combination with dopamine agonists and MAO inhibitors;
    clinical responses are variable.
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: pyridoxine
      term:
        id: CHEBI:16709
        label: pyridoxine
  target_mechanisms:
  - target: DDC Enzymatic Deficiency
    treatment_effect: MODULATES
    description: Pyridoxine provides vitamin B6 cofactor support for residual AADC activity.
  evidence:
  - reference: PMID:19172410
    reference_title: "Aromatic L-amino acid decarboxylase deficiency: clinical features, drug therapy and follow-up."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Drug regimes consisted of vitamin B6, dopamine agonists, MAO inhibitors and anticholinergics in different combinations."
    explanation: Clinical cohort lists vitamin B6 among AADC deficiency drug regimens.
  - reference: PMID:32409695
    reference_title: "The genetic and clinical characteristics of aromatic L-amino acid decarboxylase deficiency in mainland China."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Eighteen patients (78.3%) got various degree of improvement after using pyridoxine monotherapy or different combination of pyridoxine, dopamine agonists, and monoamine oxidase (MAO) inhibitors."
    explanation: Mainland China cohort supports partial improvement with pyridoxine-based regimens.
- name: Dopamine agonist and MAO inhibitor pharmacotherapy
  description: >-
    Dopamine agonists and monoamine oxidase inhibitors are used as symptomatic
    neurotransmitter-directed treatment classes, sometimes with vitamin B6 and
    anticholinergics.
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: dopamine agonist
      term:
        id: NCIT:C66884
        label: Dopamine Agonist
    - preferred_term: monoamine oxidase inhibitor
      term:
        id: NCIT:C667
        label: Monoamine Oxidase Inhibitor
  target_mechanisms:
  - target: Biogenic Monoamine Synthesis Failure
    treatment_effect: MODULATES
    description: These drugs augment dopaminergic signaling or reduce monoamine breakdown despite impaired synthesis.
  evidence:
  - reference: PMID:1357595
    reference_title: "Aromatic L-amino acid decarboxylase deficiency: clinical features, diagnosis, and treatment of a new inborn error of neurotransmitter amine synthesis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Treatment with either bromocriptine or tranylcypromine stopped the abnormal eye movements; tranylcypromine treatment also improved muscle tone"
    explanation: Original cases improved with dopamine agonist and MAO inhibitor therapy.
  - reference: PMID:19172410
    reference_title: "Aromatic L-amino acid decarboxylase deficiency: clinical features, drug therapy and follow-up."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Drug regimes consisted of vitamin B6, dopamine agonists, MAO inhibitors and anticholinergics in different combinations."
    explanation: Clinical cohort supports dopamine agonist and MAO inhibitor use.
  - reference: PMID:32409695
    reference_title: "The genetic and clinical characteristics of aromatic L-amino acid decarboxylase deficiency in mainland China."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Eighteen patients (78.3%) got various degree of improvement after using pyridoxine monotherapy or different combination of pyridoxine, dopamine agonists, and monoamine oxidase (MAO) inhibitors."
    explanation: Mainland China cohort supports partial improvement with combination regimens.
- name: Multidisciplinary supportive care
  description: >-
    Supportive care addresses feeding, sleep, mobility, seizures, and other
    neurologic or autonomic complications while disease-directed and
    symptomatic therapies are optimized.
  treatment_term:
    preferred_term: supportive care
    term:
      id: MAXO:0000950
      label: supportive care
  target_phenotypes:
  - preferred_term: Feeding difficulties
    term:
      id: HP:0011968
      label: Feeding difficulties
  - preferred_term: Sleep abnormality
    term:
      id: HP:0002360
      label: Sleep disturbance
  - preferred_term: Seizure
    term:
      id: HP:0001250
      label: Seizure
  - preferred_term: Hypotonia
    term:
      id: HP:0001252
      label: Hypotonia
  evidence:
  - reference: PMID:28100251
    reference_title: "Consensus guideline for the diagnosis and treatment of aromatic l-amino acid decarboxylase (AADC) deficiency."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "practical recommendations on clinical diagnosis, laboratory diagnosis, imaging and electroencephalograpy, medical treatments and non-medical treatments."
    explanation: Consensus guideline supports medical and non-medical care recommendations for AADC deficiency.
clinical_trials:
- name: NCT04903288
  phase: PHASE_II
  status: ACTIVE_NOT_RECRUITING
  description: >-
    Phase 2 open-label trial assessing pharmacodynamics and safety of
    eladocagene exuparvovec administered with an MR-compatible ventricular
    cannula in pediatric AADC deficiency, with extension follow-up for motor
    development, AADC-specific symptoms, and long-term safety and efficacy.
  target_phenotypes:
  - preferred_term: Motor delay
    term:
      id: HP:0001270
      label: Motor delay
  - preferred_term: Decreased CSF homovanillic acid concentration
    term:
      id: HP:0003785
      label: Decreased CSF homovanillic acid concentration
  evidence:
  - reference: clinicaltrials:NCT04903288
    reference_title: "An Open-Label Trial to Address the Safety of the SmartFlow MR-Compatible Ventricular Cannula for Administering Eladocagene Exuparvovec to Pediatric Subjects"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The primary objectives of the trial phase are to assess the pharmacodynamics (PD) of eladocagene exuparvovec treatment by evaluation of homovanillic acid (HVA) levels"
    explanation: ClinicalTrials.gov identifies pharmacodynamic assessment of eladocagene exuparvovec in AADC deficiency.
  - reference: clinicaltrials:NCT04903288
    reference_title: "An Open-Label Trial to Address the Safety of the SmartFlow MR-Compatible Ventricular Cannula for Administering Eladocagene Exuparvovec to Pediatric Subjects"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The extension phase is designed to capture additional clinical information for eladocagene exuparvovec through study evaluations, changes in motor development, AADC-specific symptoms, and other PD measures."
    explanation: Trial follow-up includes motor development, AADC-specific symptoms, and pharmacodynamic measures.
notes: >-
  AADC deficiency is distinct from disorders of dopamine synthesis upstream of
  DDC because both catecholamine and serotonin pathways are affected. Classical
  symptomatic pharmacotherapy remains variable in effect, while intraputaminal
  eladocagene exuparvovec is the disease-directed gene-addition therapy with
  documented regulatory approval.
📚

References & Deep Research

References

9
ORPHA:35708
Aromatic L-amino acid decarboxylase deficiency
1 finding
Orphanet defines AADC deficiency as a rare severe genetic neurometabolic disorder caused by impaired catecholamine and serotonin synthesis.
"A rare, severe, genetic neurometabolic disorder associated with clinical manifestations related to impaired synthesis of dopamine, noradrenaline, adrenaline and serotonin."
PMID:28100251
Consensus guideline for the diagnosis and treatment of aromatic l-amino acid decarboxylase (AADC) deficiency.
1 finding
The international consensus guideline supports autosomal recessive inheritance, early onset, key motor/autonomic symptoms, laboratory diagnosis, imaging/EEG considerations, and medical management.
"In the face of limited definitive evidence, we constructed practical recommendations on clinical diagnosis, laboratory diagnosis, imaging and electroencephalograpy, medical treatments and non-medical treatments."
PMID:19172410
Aromatic L-amino acid decarboxylase deficiency: clinical features, drug therapy and follow-up.
1 finding
A German clinical cohort supports the combined serotonin/dopamine/ catecholamine deficiency, core neurologic and extraneurologic features, characteristic CSF profile, plasma enzyme confirmation, and symptomatic drug treatment classes.
"AADC deficiency is a disorder of biogenic amine metabolism resulting in generalized combined deficiency of serotonin, dopamine and catecholamines."
PMID:36268467
Clinical Features in Aromatic L-Amino Acid Decarboxylase (AADC) Deficiency: A Systematic Review.
1 finding
A systematic review of 261 molecularly or biochemically diagnosed patients supports DDC causation, early onset, frequent hypotonia, developmental delay, oculogyric crises, hypokinesia, ptosis, dysautonomia, gastrointestinal symptoms, sleep disorders, and behavioral disorders.
"By analysing 261 patients from 41 papers with molecular and/or biochemical diagnosis of AADC deficiency for which individuality could be determined with certainty, we found symptom onset to occur in the first 6 months of life in 93% of cases."
PMID:30689738
Gene therapy improves motor and mental function of aromatic l-amino acid decarboxylase deficiency.
1 finding
An open-label phase 1/2 intraputaminal AAV-DDC study supports restored putaminal dopamine synthesis and improved motor, oculogyric, dystonic, cognitive, and verbal function after gene therapy.
"The restoration of dopamine synthesis in the putamen via gene transfer provides transformative medical benefit across all patient ages, genotypes, and disease severities included in this study."
PMID:1357595
Aromatic L-amino acid decarboxylase deficiency: clinical features, diagnosis, and treatment of a new inborn error of neurotransmitter amine synthesis.
1 finding
The original case report documents severe hypotonia, oculogyric crises, absent/reduced AADC activity, reduced biogenic amines, elevated precursors, and partial response to bromocriptine/tranylcypromine-based therapy.
"Activity of aromatic L-amino acid decarboxylase was virtually absent in a liver biopsy sample and greatly reduced in plasma."
PMID:32409695
The genetic and clinical characteristics of aromatic L-amino acid decarboxylase deficiency in mainland China.
1 finding
A 23-patient mainland China cohort supports DDC variants, early onset, hypotonia, oculogyric crises, autonomic symptoms, and frequent partial improvement with pyridoxine, dopamine agonist, and MAO inhibitor regimens.
"Eighteen patients (78.3%) got various degree of improvement after using pyridoxine monotherapy or different combination of pyridoxine, dopamine agonists, and monoamine oxidase (MAO) inhibitors."
DOI:10.1001/jama.2024.28666
Eladocagene Exuparvovec for Aromatic L-Amino Acid Decarboxylase Deficiency
1 finding
JAMA Insights reports FDA approval of Kebilidi, eladocagene exuparvovec, for AADC deficiency in adult and pediatric patients.
"This JAMA Insights discusses the US Food and Drug Administration approval of Kebilidi, eladocagene exuparvovec, for the treatment of aromatic L-amino acid decarboxylase deficiency in adult and pediatric patients."
clinicaltrials:NCT04903288
An Open-Label Trial to Address the Safety of the SmartFlow MR-Compatible Ventricular Cannula for Administering Eladocagene Exuparvovec to Pediatric Subjects
1 finding
ClinicalTrials.gov documents an active-not-recruiting phase 2 trial of eladocagene exuparvovec in pediatric AADC deficiency.
"The primary objectives of the trial phase are to assess the pharmacodynamics (PD) of eladocagene exuparvovec treatment by evaluation of homovanillic acid (HVA) levels and to assess the safety of the SmartFlow magnetic resonance compatible ventricular cannula."

Deep Research

1
Aromatic L-amino acid decarboxylase deficiency research fallback ▸

Aromatic L-amino acid decarboxylase deficiency research fallback

Provider attempts

  • Falcon deep-research: attempted with a 75 second timeout on 2026-05-06 and terminated without producing an artifact.
  • OpenAI deep-research: attempted with a 75 second timeout on 2026-05-06 and terminated without producing an artifact.
  • Perplexity deep-research: skipped after the bounded Falcon/OpenAI attempts; curation proceeded from generated Orphanet, PubMed, DOI, and ClinicalTrials.gov caches.

Literature scope used for curation

This fallback curation is based on generated reference caches for ORPHA:35708, the international consensus guideline (PMID:28100251), clinical cohort evidence (PMID:19172410, PMID:32409695), the original biochemical case report (PMID:1357595), a systematic review of 261 patients (PMID:36268467), the intraputaminal AAV-DDC gene-therapy study (PMID:30689738), the JAMA Insights FDA approval summary for eladocagene exuparvovec (DOI:10.1001/jama.2024.28666), and the ClinicalTrials.gov cache for NCT04903288.

Curation synthesis

AADC deficiency is a DDC-related autosomal recessive neurometabolic disorder. Loss of aromatic L-amino acid decarboxylase activity reduces dopamine, serotonin, norepinephrine, and epinephrine synthesis, producing early hypotonia, global developmental delay, oculogyric crises, dystonia, autonomic symptoms, and the characteristic CSF pattern of low homovanillic acid and 5-hydroxyindoleacetic acid with elevated 3-ortho-methyldopa. The YAML uses ORPHA:35708 for structured phenotype frequencies and PubMed/ClinicalTrials.gov caches for clinical mechanisms, diagnostic evidence, and treatment support.

Key references

  • ORPHA:35708
  • PMID:28100251
  • PMID:19172410
  • PMID:36268467
  • PMID:30689738
  • PMID:1357595
  • PMID:32409695
  • DOI:10.1001/jama.2024.28666
  • clinicaltrials:NCT04903288