Neuromuscular diseases
A rare disease of the nervous system present from birth. Too little dopamine and serotonin are made in the brain. Floppy muscles, developmental delay and episodes in which the eyes roll upward are seen.
Not part of the panel of Türkiye's National Newborn Screening Programme (heel-prick test). Source
This page is translated from the Turkish original.
This disease is followed through the “Neuromuscular diseases” group.
A change in the DDC gene reduces the activity of the AADC enzyme. This enzyme makes dopamine and serotonin in nerve cells. When there is too little of these messenger substances, movement and development are impaired. Automatic functions such as blood pressure, body temperature and sweating are also affected.
Symptoms usually begin in the first six months.
The levels of messenger substances in the cerebrospinal fluid are checked. The activity of the AADC enzyme is measured in the blood. A genetic test shows the change in the DDC gene. A brain MRI is often normal.
Medicines and vitamin supplements that ease symptoms are used. There is also an approved gene therapy specific to the disease. This treatment is given through brain surgery. It is approved in Europe and in the USA. Nutritional support, physiotherapy and sleep care are also important. Regular follow-up is needed. The doctor who follows the disease decides which treatment is suitable.
The disease is passed on through recessive inheritance. The mother and father are carriers who show no symptoms. For a couple who are both carriers, the chance of having an affected child is 1 in 4 in each pregnancy. Recessive diseases can be more common when relatives marry each other. Testing brothers and sisters as well helps early diagnosis. Genetic counselling is recommended.
Source: MedlinePlus Genetics: Aromatic l-amino acid decarboxylase deficiency · GeneReviews: Aromatic L-Amino Acid Decarboxylase Deficiency
These facts are taken from Orphanet and MedlinePlus records (last checked: October 7, 2026). Frequency values are approximate ranges.
Non-profit patient and family organizations in Türkiye working on this disease or disease group. Links are for information; Doktorclub is not affiliated with these organizations and does not endorse them.
We could not find a patient association specific to this disease.
For all rare diseases: Nadir Hastalıklar Federasyonu
Doktorclub does not diagnose, recommend treatments or refer you to hospitals or doctors. These pages are meant to help you talk with your doctor.
EuropeResearch and clinical trials
In France, six patients with AADC deficiency received gene therapy delivered to both sides of the brain.
A clinical trial is a regulated study that tests whether a new treatment is safe and whether it works, in patients who volunteer. Most trials look for a certain age, genetic change and health condition. Taking part is voluntary.
Questions you can ask your doctor
ClinicalTrials.gov lists 4 active interventional studies for this disease. 2 are recruiting now; none has a site in Türkiye. Last checked: October 7, 2026.
Selected records (studies with a site in Türkiye first):
Early stage: safety and dose are being tested · Phase 1 · investigational (experimental)RecruitingNCT02852213
Early stage: safety and dose are being tested · Early phase 1 · investigational (experimental)RecruitingNCT05765981
Middle stage: the effect is being tested in a small group · Phase 2 · investigational (experimental)Active, not recruitingNCT04903288
Late stage: the effect is being compared in a large group · Phase 2 / Phase 3 · investigational (experimental)Active, not recruitingNCT06432140
See all studies on ClinicalTrials.gov · Joining clinical trials
InternationalResearch and clinical trials
The HIMALAYA study, published in The Lancet Neurology, examined an experimental drug in patients with ALS (amyotrophic lateral sclerosis).
TürkiyeResearch and clinical trials
A multicenter study in Istanbul compared patients with Guillain-Barré syndrome.
USANew treatments and approvals
The US Food and Drug Administration (FDA) approved levacetylleucine for balance and walking problems in ataxia-telangiectasia (A-T).
These codes identify the disease in international classifications and databases. They can help when you talk with your doctor or look for reliable sources.
Orphanet code: ORPHA:35708
No separate ICD-11 code; WHO classifies this disease under: 5C59.00
Codes checked against WHO ICD-11 and Orphanet on October 7, 2026.
This page provides general information and does not replace diagnosis or treatment. Talk to your doctor about symptoms, diagnosis and treatment.