Getting your child tested
What to expect
To get an accurate diagnosis, your child’s doctor may perform multiple tests that are not specific for AADC deficiency, but can help identify problems in the brain, such as:
- CT scan: takes X-rays to look at different angles around the body and uses a computer to make a more detailed image
- EEG: looks for abnormalities in the brain’s activity by measuring tiny electrical charges
- MRI: uses magnetic field and radio waves to create detailed images of the body’s organs and structures
Doctors may perform additional tests if some of these test results do not give clear answers.
Core tests to diagnose AADC deficiency include:
- Genetic testing
Your child’s doctor may recommend genetic testing to look for a mutation, or change, in the DDC gene
- Plasma AADC enzyme activity
This blood test measures the amount of activity of the AADC enzyme, which is reduced in patients with AADC deficiency
- CSF neurotransmitter metabolite panel
Neurotransmitters allow the cells in the nervous system to talk to each other. This test measures the levels of some of the metabolites, or precursors and byproducts, of neurotransmitters. The test is done by collecting some of the fluid in the spine, which is known as a lumbar puncture or spinal tap
A positive result from 2 or more of these tests confirms a diagnosis of AADC deficiency.
Your child’s doctor may also order other tests that will be helpful in diagnosing your child, including:
- Blood test for 3-OMD
This simple screening test, which measures a compound called 3-OMD, can be useful if your child’s doctor suspects AADC deficiency
Your child’s doctor will work with you to explain what kind of sample is needed for each individual test.
What types of doctors can diagnose AADC deficiency?
3-OMD=3-O-methyldopa; AADC=aromatic L-amino acid decarboxylase; CSF=cerebrospinal fluid; CT=computed tomography; DDC=dopa decarboxylase; EEG=electroencephalogram; MRI=magnetic resonance imaging.
What does the diagnostic journey of AADC deficiency look like?
Hear from an expert on the experience of caring for child living with AADC deficiency.