Newborn Screening and AADC Deficiency

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by Mary Chapman |

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Newborn screening for aromatic L-amino acid decarboxylase (AADC) deficiency has been studied, but has not yet been not been implemented. This is due partly to a lack of availability and standardization of noninvasive testing methods.

Still, innovative treatment options, particularly gene therapy, have underscored the importance of early diagnosis.

What is AADC deficiency?

AADC deficiency is a genetic and neurometabolic disease. The symptoms of the disease usually emerge in early infancy. It affects the nervous system and hinders the ability of nerve cells to communicate with each other and other cells in the body.

Mutations in the DDC gene cause AADC deficiency. This gene provides instructions for making the AADC protein. AADC protein plays a critical role in the production of the neurotransmitters dopamine and serotonin.

Why is newborn screening important?

A child born with a treatable rare condition who receives a diagnosis quickly can begin treatment as soon as possible to minimize or eliminate the disease’s impact. Newborn screening can provide information to parents much earlier than they might otherwise receive it, also possibly avoiding misdiagnoses along the way.

Screening a newborn baby for an array of genetic conditions also gives parents the opportunity to plan future pregnancies in an informed way.

Newborn screening for AADC deficiency?

Because AADC deficiency is similar in presentation to more common conditions such as cerebral palsy and seizure disorders, doctors may misdiagnose it. A straightforward screening test would help facilitate diagnosis.

Early diagnosis also is key in terms of treatment. This becomes increasingly important with the development of gene therapy, which works best before the disease progresses.

Dried blood spots and AADC deficiency screening

Research has shown that a new technique using dried blood spots could help in the diagnosis of AADC deficiency, and could be implemented in a routine in newborn screening.

Dried blood spots are useful for diagnostics and screening because they are easy to collect and transport, and they are highly stable for long periods of time. They also can be useful for several analytical tests.

While this approach won’t replace current gold standards for diagnosis —  genetic testing and directly assessing the activity of the AADC protein — it could allow for the early identification of people who might benefit from such tests.


Last updated: June 3, 2020


AADC News is strictly a news and information website about the disease. It does not provide medical advice, diagnosis or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.