Aromatic L-amino acid decarboxylase deficiency

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Aromatic L-amino acid decarboxylase deficiency
Other namesAADC deficiency
Specialty Neurology   OOjs UI icon edit-ltr-progressive.svg
Symptoms Dystonia, oculogyric crises, developmental delay, parkinsonism, dysautonomia
Usual onsetInfancy
CausesAutosomal recessive DDC mutation
Diagnostic method Lumbar puncture for neurotransmitter analysis; enzyme assay; genetic testing

Aromatic L-amino acid decarboxylase deficiency, also known as AADC deficiency, is a rare genetic disorder caused by mutations in the DDC gene, which encodes an enzyme called aromatic L-amino acid decarboxylase.

Contents

Signs and symptoms

Biosynthesis and breakdown of serotonin and the catecholamines, and the metabolic block in aromatic L-amino acid decarboxylase deficiency, Wassenberg et al., 2017. Biosynthesis and breakdown of serotonin and the catecholamines, and the metabolic block in AADC deficiency.png
Biosynthesis and breakdown of serotonin and the catecholamines, and the metabolic block in aromatic L-amino acid decarboxylase deficiency, Wassenberg et al., 2017.

Babies with severe aromatic L-amino acid decarboxylase deficiency usually present during the first few months of life. Symptoms can include:

Some people may develop cerebral folate deficiency, because O-methylation of the excessive amounts of L-Dopa can deplete methyl donors such as S-adenosyl methionine and levomefolic acid. This deviation can be detected by measuring the levels of levomefolic acid in the cerebrospinal fluid, and can be corrected by folinic acid. [1]

Genetics

Aromatic L-amino acid decarboxylase deficiency has an autosomal recessive pattern of inheritance Autorecessive.svg
Aromatic L-amino acid decarboxylase deficiency has an autosomal recessive pattern of inheritance

Aromatic L-amino acid decarboxylase deficiency is an autosomal recessive condition, meaning an individual needs to have two faulty copies of the DDC gene in order to be affected. Usually, one copy is inherited from each parent. [3]

Pathophysiology

The aromatic L-amino acid decarboxylase deficiency enzyme is involved in the synthesis of dopamine and serotonin, both of which are important neurotransmitters.

Diagnosis

Once there is a clinical suspicion of the diagnosis, neurotransmitters can be analysed in cerebrospinal fluid from a lumbar puncture. If these show the pattern of abnormalities typical for aromatic L-amino acid decarboxylase deficiency, the diagnosis can be confirmed by genetic testing and/or measurement of enzyme activity.

Treatment

There is no cure for aromatic L-amino acid decarboxylase deficiency, but medical and multidisciplinary treatment can relieve some of the symptoms.[ medical citation needed ] Individuals will require physiotherapy, occupational therapy, and speech and language therapy.[ medical citation needed ] Some will need enteral feeding (for example, a gastrostomy or jejunostomy) due to difficulties with chewing and swallowing.[ medical citation needed ]

Various medications can help compensate for the missing neurotransmitters. Dopamine agonists such as rotigotine or pramipexole and monoamine oxidase inhibitors such as selegiline are commonly used.[ medical citation needed ] Individuals may also need to take a range of other medications to control dyskinesia, constipation and other symptoms. [1]

In July 2021, results of a small gene therapy phase I study reported observation of dopamine restoration on seven participants between 4 and 9 years old. [4] [5] [6]

In July 2022, the gene therapy product eladocagene exuparvovec was approved in the European Union for use in patients aged 18 months or older. [7]

Related Research Articles

<span class="mw-page-title-main">Catecholamine</span> Class of chemical compounds

A catecholamine is a monoamine neurotransmitter, an organic compound that has a catechol and a side-chain amine.

<small>L</small>-DOPA Chemical compound

l-DOPA, also known as levodopa and l-3,4-dihydroxyphenylalanine, is an amino acid that is made and used as part of the normal biology of some plants and animals, including humans. Humans, as well as a portion of the other animals that utilize l-DOPA, make it via biosynthesis from the amino acid l-tyrosine. l-DOPA is the precursor to the neurotransmitters dopamine, norepinephrine (noradrenaline), and epinephrine (adrenaline), which are collectively known as catecholamines. Furthermore, l-DOPA itself mediates neurotrophic factor release by the brain and CNS. l-DOPA can be manufactured and in its pure form is sold as a psychoactive drug with the INN levodopa; trade names include Sinemet, Pharmacopa, Atamet, and Stalevo. As a drug, it is used in the clinical treatment of Parkinson's disease and dopamine-responsive dystonia.

Aromatic <small>L</small>-amino acid decarboxylase Class of enzymes

Aromatic L-amino acid decarboxylase, also known as DOPA decarboxylase (DDC), tryptophan decarboxylase, and 5-hydroxytryptophan decarboxylase, is a lyase enzyme, located in region 7p12.2-p12.1.

<span class="mw-page-title-main">Carbidopa</span> Chemical compound

Carbidopa (Lodosyn) is a drug given to people with Parkinson's disease in order to inhibit peripheral metabolism of levodopa. This property is significant in that it allows a greater proportion of administered levodopa to cross the blood–brain barrier for central nervous system effect, instead of being peripherally metabolised into substances unable to cross said barrier.

<span class="mw-page-title-main">Benserazide</span> Chemical compound

Benserazide is a peripherally acting aromatic L-amino acid decarboxylase or DOPA decarboxylase inhibitor, which is unable to cross the blood–brain barrier.

Oculogyric crisis (OGC) is a rare sudden, paroxysmal, dystonic reaction that may manifest in response to specific drugs, particularly neuroleptics, or medical conditions, such as movement disorders. This neurological phenomenon is characterized by a sustained dystonic, conjugate, involuntary upward deviation of both eyes lasting seconds to hours. The term oculogyric is applied in reference to the simultaneous upward movement of both eyes, although the reaction may encompass a variety of additional responses. The reaction is not life-threaning.

<span class="mw-page-title-main">Aromatic amino acid</span> Amino acid having an aromatic ring

An aromatic amino acid is an amino acid that includes an aromatic ring.

<span class="mw-page-title-main">PTC Therapeutics</span> Pharmaceutical company

<span class="mw-page-title-main">Droxidopa</span> Synthetic amino acid which metabolizes into the neurotransmitter norepinephrine

Droxidopa is a synthetic amino acid precursor which acts as a prodrug to the neurotransmitter norepinephrine (noradrenaline). Unlike norepinephrine, droxidopa is capable of crossing the protective blood–brain barrier (BBB).

<span class="mw-page-title-main">Aromatic L-amino acid decarboxylase inhibitor</span>

An aromatic L-amino acid decarboxylase inhibitor is a medication of type enzyme inhibitor which inhibits the synthesis of dopamine by the enzyme aromatic L-amino acid decarboxylase. It is used to inhibit the decarboxylation of L-DOPA to dopamine outside the brain, i.e. in the blood. This is primarily co-administered with L-DOPA to combat Parkinson's disease. Administration can prevent common side-effects, such as nausea and vomiting, as a result of interaction with D2 receptors in the vomiting center located outside the blood–brain barrier.

Dopamine-responsive dystonia (DRD) also known as Segawa syndrome (SS), is a genetic movement disorder which usually manifests itself during early childhood at around ages 5–8 years.

Sepiapterin reductase deficiency is an inherited pediatric disorder characterized by movement problems, and most commonly displayed as a pattern of involuntary sustained muscle contractions known as dystonia. Symptoms are usually present within the first year of age, but diagnosis is delayed due to physicians lack of awareness and the specialized diagnostic procedures. Individuals with this disorder also have delayed motor skills development including sitting, crawling, and need assistance when walking. Additional symptoms of this disorder include intellectual disability, excessive sleeping, mood swings, and an abnormally small head size. SR deficiency is a very rare condition. The first case was diagnosed in 2001, and since then there have been approximately 30 reported cases. At this time, the condition seems to be treatable, but the lack of overall awareness and the need for a series of atypical procedures used to diagnose this condition pose a dilemma.

Gene therapy in Parkinson's disease consists of the creation of new cells that produce a specific neurotransmitter (dopamine), protect the neural system, or the modification of genes that are related to the disease. Then these cells are transplanted to a patient with the disease. There are different kinds of treatments that focus on reducing the symptoms of the disease but currently there is no cure.

3-<i>O</i>-Methyldopa Chemical compound

3-O-Methyldopa (3-OMD) is one of the most important metabolites of L-DOPA, a drug used in the treatment of the Parkinson's disease.

<span class="mw-page-title-main">Cerebral folate deficiency</span> Medical condition

Cerebral folate deficiency is a condition in which concentrations of 5-methyltetrahydrofolate are low in the brain as measured in the cerebral spinal fluid despite being normal in the blood. Symptoms typically appear at about 5 to 24 months of age. Without treatment there may be poor muscle tone, trouble with coordination, trouble talking, and seizures.

Dihydropteridine reductase deficiency (DHPRD) is a genetic disorder affecting the tetrahydrobiopterin (BH4) synthesis pathway, inherited in the autosomal recessive pattern. It is one of the six known disorders causing tetrahydrobiopterin deficiency, and occurs in patients with mutations of the QDPR gene.

<span class="mw-page-title-main">Monoamine precursor</span>

Monoamine precursors are precursors of monoamines and monoamine neurotransmitters in the body. The amino acids L-tryptophan and L-5-hydroxytryptophan are precursors of serotonin and melatonin, while the amino acids L-phenylalanine, L-tyrosine, and L-DOPA (levodopa) are precursors of dopamine, epinephrine (adrenaline), and norepinephrine (noradrenaline). Administration of monoamine precursors can increase the levels of monoamine neurotransmitters in the body and brain. Monoamine precursors may be used in combination with peripherally selective aromatic L-amino acid decarboxylase inhibitors such as carbidopa and benserazide. Carbidopa/levodopa is used to increase brain dopamine levels in the treatment of Parkinson's disease while carbidopa/oxitriptan (EVX-101) is under development as an antidepressant for possible use in the treatment of depression.

Eladocagene exuparvovec, sold under the brand name Upstaza, is a gene therapy product for the treatment of aromatic L‑amino acid decarboxylase (AADC) deficiency. It infuses the gene encoding for the human AADC enzyme into the putamen region of the brain. The subsequent expression of AADC results in dopamine production and, as a result, development of motor function in patients with AADC deficiency.

Autosomal recessive GTP cyclohydrolase I deficiency (AR-GTPCHD) is a disorder associated with the deficient operation of the enzyme GTP cyclohydrolase I. The condition leads to insufficient production of the cofactor tetrahydrobiopterin necessary for the proper synthesis of dopamine and serotonin and for maintenance of adequate levels of phenylalanine. As of 2020, autosomal recessive GTP cyclohydrolase I deficiency was one of the six known causes of tetrahydrobiopterin deficiency. It is also considered part of the spectrum of dopa-responsive dystonias.

Tyrosine hydroxylase deficiency (THD) is a disorder caused by disfunction of tyrosine hydroxylase, an enzyme involved in the biosynthesis of dopamine. This condition is one of the causes of dopa-responsive dystonia.

References

  1. 1 2 3 Wassenberg T, Molero-Luis M, Jeltsch K, Hoffmann GF, Assmann B, Blau N, et al. (January 2017). "Consensus guideline for the diagnosis and treatment of aromatic l-amino acid decarboxylase (AADC) deficiency". Orphanet J Rare Dis. 12 (1): 12. doi:10.1186/s13023-016-0522-z. PMC   5241937 . PMID   28100251.
  2. ↑ Korenke, GC; Christen, HJ; Hyland, K; Hunneman, DH; Hanefeld, F (1997). "Aromatic L-amino acid decarboxylase deficiency: an extrapyramidal movement disorder with oculogyric crises". Eur J Paediatr Neurol. 1 (2–3): 67–71. doi:10.1016/S1090-3798(97)80065-7. PMID   10728198.
  3. ↑ Montioli, Riccardo; Dindo, Mirco; Giorgetti, Alejandro; Piccoli, Stefano; Cellini, Barbara; Voltattorni, Carla Borri (2014). "A comprehensive picture of the mutations associated with aromatic amino acid decarboxylase deficiency: From molecular mechanisms to therapy implications". Human Molecular Genetics. 23 (20): 5429–5440. doi: 10.1093/hmg/ddu266 . PMID   24865461.
  4. ↑ Pearson TS, Gupta N, San Sebastian W, Imamura-Ching J, Viehoever A, Grijalvo-Perez A, et al. (July 2021). "Gene therapy for aromatic L-amino acid decarboxylase deficiency by MR-guided direct delivery of AAV2-AADC to midbrain dopaminergic neurons". Nature Communications. 12 (1): 4251. Bibcode:2021NatCo..12.4251P. doi:10.1038/s41467-021-24524-8. ISSN   2041-1723. PMC   8275582 . PMID   34253733.
  5. ↑ Ibrahim, Mennatalla (2021-07-14). "Gene therapy restores missing dopamine in children with rare brain disease". Science. Retrieved 2021-07-18.
  6. ↑ "Gene therapy trial points to a wider window to alter course of rare disease". STAT. 2021-07-12. Retrieved 2021-07-18.
  7. ↑ Keam, S. J. (2022). "Eladocagene Exuparvovec: First Approval". Drugs. 82 (13): 1427–1432. doi:10.1007/s40265-022-01775-3. PMID   36103022. S2CID   252213561.
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