Aromatic L-amino acid decarboxylase deficiency: perspectives on diagnosis and management

Stacey KH Tay,^1,2 Furene SJ Wang,² Jeremy BY Lin<sup>2

1</sup>Department of Pediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; ²Khoo Teck Puat-National University Children’s Medical Institute, National University Hospital, Singapore

Abstract: Aromatic L-amino acid decarboxylase (AADC) deficiency is an autosomal recessive neurotransmitter defect that results in a combined central deficiency of monoamines, namely catecholamines and serotonin. To date, less than 100 patients have been described with AADC deficiency, most with a severe neurological phenotype. This review article illustrates the pathophysiology, diagnostic methods, and therapeutic strategies for patients with AADC deficiency. Two patients in our institution have extremely mild phenotypes and their robust response to treatment illustrates the variable severity of this condition and the need for early diagnosis of this potentially treatable disease.

Keywords: aromatic amino acid decarboxylase deficiency, AADC deficiency, dopa decarboxylase gene, DDC gene, dopamine deficiency, neurotransmitter disorder