Aromatic l-amino acid decarboxylase (AADC) deficiency is an inherited disorder that affects the way signals are passed between certain cells in the nervous system.

Signs and symptoms of AADC deficiency generally appear in the first year of life. Affected infants may have severe developmental delay, weak muscle tone (hypotonia), muscle stiffness, difficulty moving, and involuntary writhing movements of the limbs (athetosis). They may be lacking in energy (lethargic), feed poorly, startle easily, and have sleep disturbances. People with AADC deficiency may also experience episodes called oculogyric crises that involve abnormal rotation of the eyeballs; extreme irritability and agitation; and pain, muscle spasms, and uncontrolled movements, especially of the head and neck.

AADC deficiency may affect the autonomic nervous system, which controls involuntary body processes such as the regulation of blood pressure and body temperature. Resulting signs and symptoms can include droopy eyelids (ptosis), constriction of the pupils of the eyes (miosis), inappropriate or impaired sweating, nasal congestion, drooling, reduced ability to control body temperature, low blood pressure (hypotension), backflow of acidic stomach contents into the esophagus (gastroesophageal reflux), low blood glucose (hypoglycemia), fainting (syncope), and cardiac arrest.

Signs and symptoms of AADC deficiency tend to worsen late in the day or when the individual is tired, and improve after sleep.

• 25% chance that the child will have AADC deficiency
• 50% chance that the child will be a carrier of AADC deficiency like the parents
• 25% chance that the child will have two working copies of DDC, so the child will not have AADC deficiency and will not be a carrier.

• Dopamine receptor agonists
• Monoamine oxidase (MAO) inhibitor
• Pyridoxine (Vitamin B6)

• Anticholinergic agents to treat movement disorders
• Seizure medication
• Gastrointestinal medications
• Melatonin to treat sleep disturbances