Natural history of aromatic L-amino acid decarboxylase deficiency in Taiwan

Abstract

Objectives: Aromatic l-amino acid decarboxylase (AADC) deficiency is a rare inherited disorder of monoamine neurotransmitter synthesis; this deficiency leads to psychomotor delay, hypotonia, oculogyric crises, dystonia, and extraneurological symptoms. This study aimed to provide further insight into the clinical course of AADC deficiency in Taiwan. Patients and Methods: We present a retrospective, descriptive, single-center study of 37 children with a confirmed diagnosis of AADC deficiency. Their medical histories were reviewed for motor milestones, motor development, DDC mutation, and body weight. The termination point for each patient in this study was defined as no further follow-up, death, or enrollment in a gene therapy trial. Results: The median age of the study patients at the end of the study was 4.39 years (1.28–11.30). Of the 37 patients, 36 did not develop full head control, sitting ability, standing ability, or speech at any time point from birth to the termination points. Motor scales were administered to 22 patients. Their Alberta Infant Motor Scale scores were below the fifth percentile, and their Peabody Developmental Motor Scales, Second Edition, scores were below the first percentile. Their body weights were normal in the first few months of life, but severe growth retardation occurred at later ages. The mutation c.714+4A>T (IVS6+4A>T) accounted for 76% of all their DDC mutations. Conclusion: In this chapter, we report the clinical course of AADC deficiency in Taiwan. Our data will help guide the development of treatment strategies for the disease.