Medical Policy

This document addresses gene therapy for aromatic L-amino acid decarboxylase (AADC) deficiency, which is a genetic disease involving variations in the human dopa decarboxylase (DDC) gene that reduces an individual’s ability to synthesize dopamine and serotonin from their precursor molecules. These chemicals are essential neurotransmitters that control many vital physiological functions such as sleep, memory, learning, brain development and cardiovascular function. A gene therapy product to treat AADC deficiency has been approved by the U.S. Food and Drug Administration (FDA), eladocagene exuparvovec-tneq (Kebilidi^™). In Kebilidi therapy, an adeno-associated virus vector containing a functional copy of the human DDC gene is delivered directly into the brain through stereotactic injections. The viral vector infects the brain’s cells and causes a switch in the target genetic code, with the goal of allowing nerve cells to produce the missing enzyme.

Note: For a high-level overview of this document, please see “Summary for Members and Families” below.

Investigational and Not Medically Necessary:

Gene therapy for aromatic L-amino acid decarboxylase deficiency using eladocagene exuparvovec-tneq is considered investigational and not medically necessary for all indications.

This document describes clinical studies and expert recommendations, and explains whether gene therapy for aromatic L-amino acid decarboxylase deficiency is appropriate. The following summary does not replace the medical necessity criteria or other information in this document. The summary may not contain all of the relevant criteria or information. This summary is not medical advice. Please check with your healthcare provider for any advice about your health.

Key Information

Aromatic L-amino acid decarboxylase (AADC) deficiency is a rare genetic disorder that prevents the body from making certain important brain chemicals, including dopamine and serotonin. These chemicals affect movement, sleep, learning, emotions, and body functions. The FDA recently approved a gene therapy called eladocagene exuparvovec-tneq (Kebilidi) to treat AADC deficiency. This therapy delivers a working version of the DDC gene directly into the brain using a specially designed virus. A trained neurosurgeon injects the therapy into a specific part of the brain that controls movement. The goal is to help the brain make more of the missing enzyme and reduce symptoms. While some children in early studies improved after receiving Kebilidi, others did not. Some developed side effects. Experts say more research is needed to understand how well this treatment works in the long term and whether it improves the overall course of the disease.

What the Studies Show

Eladocagene exuparvovec-tneq is a one-time brain injection using a virus to deliver a healthy DDC gene to brain cells. In studies of children with AADC deficiency, gene therapy increased dopamine levels in the brain and improved some movement and developmental skills over time. For example, in one study, 86% of children reached a meaningful improvement in motor skills by 18 months after treatment. Improvements in thinking and communication were also seen. However, some children, especially older ones, did not improve much, and a few even lost some skills years after treatment. The treatment did not raise serotonin levels, which may limit how much it helps overall.

The treatment is given through brain surgery, which carries serious risks, such as bleeding or infection. In one study, all children had side effects, such as fever or unusual movements. Most side effects were mild or moderate and improved over time. The best outcomes were seen in children who received treatment before age 2, but very young children (under 1.5 years) cannot receive this therapy because their skull bones are still forming. Some drug treatments that target the same brain chemicals have been used, but studies show they help only a few people and often not very much.

Is this clinically appropriate?

This treatment is not appropriate because it has not been proven to improve health. While early studies show promise, they included small numbers of children and had no comparison group. Some children improved, but others did not. Most studies have only followed children for a few years, so long-term benefits and risks remain unknown. Expert groups recommend tracking people who get this therapy for at least 15 years to better understand outcomes. More high-quality research is needed to know if eladocagene exuparvovec-tneq gene therapy helps most people with AADC deficiency.

(Return to Description/Scope)

Summary

This document addresses aromatic L-amino acid decarboxylase (AADC) deficiency, a rare, inherited, and often fatal neurologic disorder caused by pathogenic variants in the dopa decarboxylase (DDC) gene that impair dopamine and serotonin synthesis. AADC deficiency presents early in life with severe motor, cognitive, and autonomic dysfunction, and current medical treatments such as vitamin B6, dopamine agonists, and monoamine oxidase inhibitors provide limited benefit. Eladocagene exuparvovec-tneq (Kebilidi™) is a one-time gene therapy delivered via stereotactic neurosurgery directly into the putamen using an adeno-associated viral vector carrying a functional DDC gene. The therapy aims to restore AADC enzyme activity and dopamine production in targeted brain regions and has received regulatory approval in Europe (Upstaza™) and the United States, with restrictions related to age and skull maturity.

Clinical studies involving small, single-arm cohorts demonstrate that eladocagene exuparvovec-tneq increases biomarkers of dopamine production and is associated with improvements in motor, cognitive, and language development, particularly when administered at younger ages. Imaging and cerebrospinal fluid analyses support sustained dopamine production for up to 5 years in some individuals, and many participants achieved new motor milestones. However, serotonin levels were not significantly improved, reflecting the therapy’s anatomical limitation to the putamen. Safety concerns include risks associated with invasive neurosurgery and treatment-emergent adverse events such as fever and dyskinesia, most of which were transient or manageable.

Despite promising early efficacy, significant uncertainties remain regarding long-term durability, variability of response, and the ability of the therapy to alter the overall natural history of AADC deficiency. Evidence is limited by small sample sizes, lack of control groups, and heterogeneous outcomes at long-term follow-up, with some participants showing functional decline years after treatment. Expert groups recommend structured, long-term follow-up and registry-based data collection to better understand outcomes and risks. Overall, while eladocagene exuparvovec-tneq represents a major therapeutic advance for a devastating ultra-rare disease, its clinical role continues to be defined amid ongoing questions about optimal timing, durability, and long-term benefit.

Discussion

Viral vector gene therapy

Gene therapy for AADC deficiency involves a non-replicating recombinant adeno-associated virus serotype 2 (AAV2) based vector containing the DNA of the human DDC gene under the control of the cytomegalovirus immediate-early promoter. The modified AAV2 virus is delivered as gene therapy directly into the brain through stereotactic injections. The one-time treatment is designed to correct the underlying genetic defect by delivering a functioning DDC gene directly into the putamen, a structure in the brain that plays a role in motor control, learning, speech, and other important physiological functions. The concept is that the AADC enzyme is then properly expressed in the brain cells, dopamine production is restored, and the symptoms of AADC deficiency are ameliorated.

Eladocagene exuparvovec-tneq

Eladocagene exuparvovec-tneq (Kebilidi) is a gene therapy medicinal product comprised of a genetically engineered AAV2 vector that expresses the human AADC enzyme (AAV2-hAADC). It is produced in vitro in human embryonic kidney cells by recombinant DNA technology. The product contains 2.8 × 10¹¹ vector genomes (vg)/0.5 mL solution for infusion. It is administered by a qualified neurosurgeon via stereotactic injection into the brain as a bilateral infusion (2 infusions per putamen). A total dose of 1.8 × 10¹¹ vg is delivered as four 0.08 mL (0.45 × 10¹¹ vg) infusions (two per putamen).

In a published report detailing the use of eladocagene exuparvovec-tneq gene therapy to treat human AADC deficiency, 26 individuals without head control received bilateral intraputaminal infusions of the product and completed 1-year follow-up evaluations (Tai, 2022). These individuals were enrolled in one of three consecutive trials that employed the same treatment protocol (compassionate use [n=8], phase I/II [NCT01395641; n=10], and phase IIb [NCT02926066; n=8]). A confirmed diagnosis of severe AADC deficiency was needed for inclusion by fulfilling all of the following requirements:

• Decreased levels of homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA) in cerebrospinal fluid (CSF)
• Increased levels of blood or CSF 3-O-methyldopa (3-OMD)
• Presence of at least one pathogenic DDC gene variant
• Classical symptoms of AADC deficiency

All individuals were at least 2 years old or, if younger, had skull bones suitable for the surgery (closed anterior fontanelle). The oldest participants were aged 8 years. All enrolled individuals were of Chinese descent except for one who identified as Caucasian/Thai.

Results showed that dopamine production was increased after eladocagene exuparvovec-tneq treatment. Analysis of CSF HVA and 5-HIAA reflect the levels of dopamine and serotonin in the brain, respectively. Before gene therapy, individuals had very low levels of HVA in the CSF (mean ± SD, 6.6 ± 11.2 nmol/L), but the levels increased to 30.2 ± 16.7 nmol/L 1 year after gene therapy (p<0.001). CSF levels of 5-HIAA did not significantly increase after gene therapy. Evidence of de novo dopamine production was derived from positron emission tomography (PET) imaging with a ¹⁸F-DOPA tracer that can be converted to ¹⁸F-dopamine by AADC activity and taken up by nerve cells in the putamen. At baseline, individuals had a mean ¹⁸F-DOPA-specific uptake of 0.23 ± 0.14 (n=24) that increased at 12 months (0.48 ± 0.24; n=24, p<0.001), 2 years (0.55 ± 0.24; n=15; p=0.003), and 5 years (0.60 ± 0.20; n=13; p<0.001) after gene therapy. PET data at 5 years were said to demonstrate the durability of the gene therapy effects and were consistent with motor function milestone development.

The Peabody Developmental Motor Scales-Second Edition (PDMS-2) and the Alberta Infant Motor Scale (AIMS) tools were used to measure children’s motor ability. Before gene therapy, individuals had a very low mean baseline PDMS-2 score of 10.4 ± 5.4 (n=25). Healthy 3-year-old children may have a score of 400. The baseline PDMS-2 score increased rapidly at 1 year (80.5 ± 43.4; n=25), 2 years (114.5 ± 55.2; n=22), and 5 years after gene therapy (116.1 ± 59.8; n =11) (p< 0.01 for all comparisons vs. baseline). Cognitive and language functions were assessed using the Bayley Scale of Infant and Toddler Development, Third Edition (Bayley-III). The Bayley-III cognitive score increased from baseline (11.2 ± 3.0; n=18) at 1 year (23.2 ± 6.4; n=18; p<0.001), 2 years (27.3 ± 7.4; n=16; p<0.001), and 5 years (27.8 ± 9.7; n=6; p=0.006). The Bayley-III language scores similarly increased after gene therapy from baseline (17.2 ± 2.8; n=18) to 1 year (24.6 ± 2.6; n=18; p< 0.001), 2 years (26.9 ± 5.0; n=16; p<0.001), and 5 years (27.9 ± 3.6; n=6; p=0.007). Healthy 3-year-old children may have a score of 70.

The safety of eladocagene exuparvovec-tneq treatment was also evaluated. The procedure to administer eladocagene exuparvovec-tneq involves invasive stereotactic neurosurgery to inject the genetically modified viral particles into the brain through an intracranial cannula. Potential risks of this procedure include CSF leakage, intracranial hemorrhage, infection, anemia, and wound complications. Ten individuals experienced adverse events related to the surgery, including 3 with CSF leakage, but all resolved. All participants experienced at least one treatment-emergent adverse event (TEAE) during the study. The two most commonly reported TEAEs were fever and dyskinesia. Most dyskinesia events were mild or moderate in severity and occurred within 3 months of eladocagene exuparvovec-tneq administration. Most participants had a positive anti-AAV2 antibody response within the first year after treatment, but immune responses to the viral vector are not expected to affect localized brain gene therapy. Two participants who achieved walking backwards at week 48 were treated before 2 years of age. The 4 participants who were unable to achieve new gross motor milestones at week 48 were treated between the ages of 2.8 and 10.8 years.

However, despite the promising results in terms of efficacy and safety in these early trials of eladocagene exuparvovec-tneq, the extent to which this approach is capable of changing the natural history of AADC deficiency in most affected individuals is unclear and will strongly depend on the ability to identify and treat this disorder shortly after its initial presentation and before the onset of brain damage (Himmelreich, 2019). Although symptoms of AADC deficiency emerge within the first year of life, nearly all individuals with this condition experience significant delays in accurate diagnosis. Tai and colleagues (2022) found that younger age was associated with greater improvement after eladocagene exuparvovec-tneq treatment. The increase in PDMS-2 total scores had a negative correlation with age, indicating that younger individuals exhibited faster and greater improvements after eladocagene exuparvovec-tneq gene therapy. Currently, individuals aged less than 1.5 years are not able receive this therapy due to surgical technical limitations owing to the unstable skull structure of the partially fused anterior fontanel.

Furthermore, there is limited clinical evidence for benefit of dopamine agonists and monoamine oxidase (MAO) inhibitors, which target the same biological pathways as eladocagene exuparvovec-tneq therapy. All of these treatments seek to elevate neurotransmitter activity in the brain. Dopamine agonists activate dopamine receptors and MAO inhibitors prevent the breakdown of serotonin and dopamine. However, the evidence for effectiveness of medical therapies has been limited, with respect to both the proportion of responders and the degree of observed symptomatic improvement. These drug therapies have been evaluated only in small case series or uncontrolled studies, and the quality of the resulting evidence is regarded as low or very low, in addition to providing little guidance as to optimal dosage or duration/frequency of treatment (Himmelreich, 2019).

The durability of treatment with eladocagene exuparvovec-tneq is also in question. Participants in the compassionate use study (n=5) have been followed the longest, for a period of 6-10 years. Participants had variable results at long-term follow-up, with 3 individuals having stable functional PDMS-2 and AIMS scores and 2 others showing a decline in motor function 3-5 years after gene therapy (Tai, 2022).

On July 18, 2022, eladocagene exuparvovec (marketed in Europe with the brand name Upstaza^™) received its first approval by the European Medicines Agency. It was approved for use in individuals aged 18 months and older with a clinical, molecular, and genetically confirmed diagnosis of AADC deficiency with a severe phenotype (that is, who cannot sit, stand or walk). There is limited experience in people aged 12 years and older, and the safety and efficacy of Upstaza in these individuals have not been established. The product was approved for one-time administration only; repeat administration of Upstaza and its use for the treatment of other indications has not been evaluated.

On November 13, 2024, the FDA approved a single-dose intraputaminal infusion of Kebilidi for the following indication: “KEBILIDI (eladocagene exuparvovec-tneq) is an adeno-associated virus (AAV) vector-based gene therapy indicated for the treatment of adult and pediatric patients with aromatic L-amino acid decarboxylase (AADC) deficiency.” Kebilidi is contraindicated for individuals who have not achieved skull maturity assessed by neuroimaging.

The following warnings and precautions for Kebilidi were listed in the product insert:

• Procedural complications: Monitor patients for procedural complications for neurosurgery, including events of respiratory and cardiac arrest after administration of KEBILIDI. (5.1)
• Dyskinesia: Monitor patients for dyskinesia after treatment with KEBILIDI. The use of dopamine antagonists can be used to control dyskinesia symptoms. (5.2)

In the product insert, the FDA cited one open-label, single arm study that evaluated the efficacy of Kebilidi (NCT04903288). The study enrolled 13 pediatric individuals aged 1.3 to 10.8 years with genetically confirmed, severe AADC deficiency who had achieved skull maturity assessed with neuroimaging. The main outcome measure was gross motor milestone achievement evaluated at week 48 and assessed using the PDMS-2. One participant dropped out of the study before week 48. Eight (67%) of the 12 treated individuals who were assessed at week 48 achieved a new gross motor milestone. Two participants who achieved walking backwards at week 48 were treated before 2 years of age. The 4 participants who were unable to achieve new gross motor milestones at week 48 were treated between the ages of 2.8 and 10.8 years. There was no comparison group which limits the generalizability of the study.

In 2024, the International Working Group on Neurotransmitter related Disorders (iNTD) published recommendations for the preparation, management, and follow-up of individuals with AADC deficiency who undergo gene therapy (Roubertie, 2024). The iNTD stated that follow-up after gene therapy with eladocagene exuparvovec is necessary until at least 15 years (after 2 years, at least once a year) in order to scientifically document the long-term outcomes. Such long-term follow-up is important in order to understand whether clinical benefits, including both symptoms and developmental progress, are sustained and continue to improve over time. It is also important to monitor for any delayed complications that may emerge. The authors concluded that:

Due to lack of data on long-term outcomes and the comparative efficacy of alternative stereotactic procedures and brain target sites, a structured follow-up plan and systematic documentation of outcomes in a suitable, industry-independent registry study are necessary.

Hwu and colleagues (2025) analyzed data from 30 individuals treated with eladocagene exuparvovec in 3 single-arm clinical studies. The objective was to characterize clinically meaningful change in motor function, as measured by the PDMS-2 score, and assess correlations with cognition and language domains of the Bayley-III tool and motor milestone achievements. A meaningful score difference (MSD) of 40 points for the PDMS-2 was chosen for analysis. It was estimated that 50% of individuals treated with eladocagene exuparvovec achieved the MSD at 6 months, and 86% at 18 months. Correlations between the change from baseline (CFB) PDMS-2 and Bayley-III scores (cognition and language domains) were of large magnitude and statistically significant from month 6 onwards: r=0.599 (p=0.0032) at month 6, r=0.796 (p=0.0002) at month 18, and r=0.861 (p=0.0007) at month 60. Median follow-up for motor milestone assessments was 60 months. The authors noted that this study is limited by small sample sizes in the data, especially at later time points, which may impact the robustness of results for correlations between CFB in PDMS-2 and Bayley-III scores over time.

In summary, while eladocagene exuparvovec-tneq therapy appears to impact some symptoms of AADC deficiency, it does not address all aspects of the enzyme deficiency since the treatment is limited to one brain structure. There is a wide range of clinical presentations of this condition and diagnosis is often difficult and delayed, possibly hindering optimal timing of delivery of gene therapy. There is limited evidence for clinical benefit of AADC treatments that target dopaminergic pathways. This gene therapy can only be administered at highly specialized treatment centers by a neurosurgeon experienced in stereotactic neurosurgeries and capable of delivering infusions to the putamen. Administration of this gene therapy to the putamen does not increase levels of serotonin, which is produced in the brainstem. Long term outcomes of this therapy are uncertain.

Aromatic L-amino acid decarboxylase (AADC) deficiency is a rare, fatal, inborn error of neurotransmitter biosynthesis affecting the central nervous system (CNS). Mutations in the dopa decarboxylase (DDC) gene alter or abolish the activity of the AADC enzyme leading to a reduction in CNS levels of neurotransmitters such as dopamine, noradrenalin (norepinephrine), adrenalin (epinephrine), serotonin, and melatonin (Keam, 2022). A total of 82 DDC gene variants leading to AADC deficiency have been identified for all known individuals with this condition (n=123) (Himmelreich, 2019).

Most individuals with AADC deficiency show severe disability from the first months of life, fail to achieve developmental milestones, and frequently cannot sit, stand or walk. Signs and symptoms of AADC deficiency include loss of head control or other early motor skills, speech loss, involuntary eye movements where eyes suddenly roll upwards, excessive crying, sweating and drooling, sleep disturbances, feeding difficulties, intellectual disability, frequent vomiting, and behavioral problems. There is wide variability in the clinical presentation of AADC deficiency, and the intensity of individual symptoms in specific cases can range from mild to very severe. Individuals with AADC deficiency are at a high risk of early death in the first decade of life (Simons, 2023).

A definitive diagnosis of AADC deficiency is made by fulfilling all of the following criteria: decreased levels of CSF homovanillic acid (HVA; a dopamine metabolite) and 5-hydroxyindoleacetic acid (5-HIAA; a serotonin metabolite), elevated blood or CSF levels of 3-O-methyldopa (3-OMD), the presence of at least one pathogenic variant in the DDC gene, and classical symptoms of AADC deficiency (Wassenberg, 2017).

There is no curative treatment for AADC deficiency. Treatment of symptoms using combinations of vitamin B6, dopamine agonists and monoamine oxidase inhibitors (all recommended as first-line treatments) has shown only limited success, especially in cases where individuals have severe impairments (Himmelreich, 2019). Ongoing physical, occupational, and speech therapy and other interventions are required to manage severe complications such as infections, feeding difficulties and breathing problems which may be life-threatening (Keam, 2022).

AADC deficiency is an ultra-rare condition estimated to affect fewer than 50 people in the United States (DiBacco, 2023). The actual prevalence may be higher, around 1-2 per million in the U.S., as it is likely underdiagnosed or misdiagnosed due to similarity with other conditions (NORD, 2024). AADC deficiency is more prevalent in Asian populations (especially Taiwanese and Japanese), probably due to a founder effect (Wassenberg, 2017). In Taiwan, the incidence of cases from 1996 to 2022 was 1:88,538 births (Hwu, 2023).

AADC deficiency is inherited in an autosomal recessive manner. An individual will be affected if a disease-causing gene variant is inherited from each parent. Individuals with one altered copy of the gene and one normal copy are carriers for the disease, but are generally asymptomatic (NORD, 2024).

Autosomal recessive disorder: An inherited condition for which two copies of an abnormal gene must be present in order for the disease or trait to develop.

Dyskinesia: A movement disorder that causes involuntary muscle movements, such as tics, tremors, or shakes.

Gene therapy: A medical treatment that introduces or alters genetic material to replace the function of a missing or dysfunctional gene with the goal of lessening or eliminating a disease process that results from genetic dysfunction.

Neurotransmitter: A chemical substance that is made and released by nerve cells causing the transfer of nerve impulses to another nerve fiber, a muscle fiber, or some other structure.

Putamen: A structure in the brain that plays a role in motor control, learning, speech articulation and other physiological functions controlled by the neurotransmitter dopamine. There is one putamen on each side of the brain, for a total of two.

The following codes for treatments and procedures applicable to this document are included below for informational purposes. Inclusion or exclusion of a procedure, diagnosis or device code(s) does not constitute or imply member coverage or provider reimbursement policy. Please refer to the member's contract benefits in effect at the time of service to determine coverage or non-coverage of these services as it applies to an individual member.

When services are Investigational and Not Medically Necessary:
For the following procedure codes, or when the code describes a procedure indicated in the Position Statement section as investigational and not medically necessary.

Peer Reviewed Publications:

1. DiBacco ML, Hinahara J, Goss TF, Pearl PL. Burden of illness in aromatic l-amino acid decarboxylase deficiency. Ann Child Neurol Soc. 2023; 1(1):75-78.
2. Himmelreich N, Montioli R, Bertoldi M, et al. Aromatic amino acid decarboxylase deficiency: molecular and metabolic basis and therapeutic outlook. Mol Genet Metab. 2019; 127(1):12-22.
3. Hwu W-L, Hsu R-H, Li M-H, et al. Aromatic l‐amino acid decarboxylase deficiency in Taiwan. JIMD Rep. 2023; 64(5):387-392.
4. Hwu WL, Lee HM, Peipert JD, et al. Clinically meaningful improvements after gene therapy for aromatic L-amino acid decarboxylase deficiency (AADCd) in the Peabody Developmental Motor Scale, Second Edition (PDMS-2) and correlation with Bayley-III scores and motor milestones. Orphanet J Rare Dis. 2025; 20(1):58.
5. Keam SJ. Eladocagene exuparvovec: first approval. Drugs. 2022; 82:1427-1432.
6. Simons CL, Hwu W-L, Zhang R, et al. Long-term outcomes of eladocagene exuparvovec compared with standard of care in aromatic l-amino acid decarboxylase (AADC) deficiency: a modelling study. Adv Ther. 2023; 40:5399-5414.
7. Tai C-H, Lee N-C, Chien Y-H, et al. Long-term efficacy and safety of eladocagene exuparvovec in patients with AADC deficiency. Mol Ther. 2022; 30(2):509-518.
8. Wassenberg T, Molero-Luis M, Jeltsch K, et al. Consensus guideline for the diagnosis and treatment of aromatic l-amino acid decarboxylase (AADC) deficiency. Orphanet J Rare Dis. 2017; 12:12.

Government Agency, Medical Society, and Other Authoritative Publications:

1. ClinicalTrials.gov [Internet]. Bethesda (MD): National Library of Medicine (US). Available at: https://clinicaltrials.gov/ct2/home. Accessed on February 13, 2026.
   • A Phase I/II Clinical Trial for Treatment of Aromatic L-amino Acid Decarboxylase (AADC) Deficiency Using AAV2-hAADC. NCT01395641.
   • A Clinical Trial for Treatment of Aromatic L-amino Acid Decarboxylase (AADC) Deficiency Using AAV2-hAADC - An Expansion. NCT02926066.
   • A Study of SmartFlow Magnetic Resonance (MR) Compatible Ventricular Cannula for Administering Eladocagene Exuparvovec to Pediatric Participants. NCT04903288.
2. European Medicines Agency. Upstaza product information. Last updated: March 26, 2024. Available at: https://www.ema.europa.eu/en/documents/product-information/upstaza-epar-product-information_en.pdf. Accessed on February 13, 2026.
3. Roubertie A, Opladen T, Brennenstuhl H, et al. Gene therapy for aromatic L-amino acid decarboxylase deficiency: requirements for safe application and knowledge-generating follow-up. J Inherit Metab Dis. 2024; 47(3):463-475.
4. U.S. Food and Drug Administration. KEBILIDI^™ highlights of prescribing information. Revised 11/2024. Available at: https://www.fda.gov/media/183530/download?attachment. Accessed on February 13, 2026.

1. National Library of Medicine. Aromatic l-amino acid decarboxylase deficiency. Last updated: May 13, 2024. Available at: https://medlineplus.gov/genetics/condition/aromatic-l-amino-acid-decarboxylase-deficiency/. Accessed on February 13, 2026.
2. National Organization for Rare Disorders (NORD). Aromatic l-amino acid decarboxylase deficiency. Last updated: November 14, 2024. Available at: https://rarediseases.org/rare-diseases/aromatic-l-amino-acid-decarboxylase-deficiency/. Accessed on February 13, 2026.

Eladocagene exuparvovec
Kebilidi
Upstaza

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