Fast Five Quiz: Aromatic L-Amino Acid Decarboxylase Deficiency Diagnosis and Management

Stephen L. Nelson, Jr, MD, PhD; Germaine L. Defendi, MD, MS, FAAP


February 07, 2022

BH4 deficiency, also inherited as an autosomal recessive condition, is clinically similar to AADC deficiency. It usually presents within the first 6 months of life. Developmental delays can occur, and severe cases can be characterized by hypotonia of the trunk, hypertonia of the limbs, hypokinesia, athetosis, seizures, and swallowing difficulties. Normal levels of CSF pterins (neopterin, dihydrobiopterin, and BH4), as seen in AADC deficiency, are not present in BH4 disorders.

Other disorders that may mimic AADC deficiency include sepiapterin reductase deficiency, succinic semialdehyde dehydrogenase deficiency, tyrosine hydroxylase deficiency, and cerebral palsy. The rare genetic diseases Gaucher disease and mucopolysaccharidoses are lysosomal storage disorders, whereas alpha-1-antitrypsin deficiency causes significant pulmonary and hepatic disease. All of these genetic disorders are clinically distinct from AADC deficiency.

Learn more about the differential diagnosis of AADC deficiency.


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.