Aromatic L-amino acid decarboxylase deficiency: overview of clinical features and outcomes.

In this paper, we provide a brief update of diagnostic considerations and biochemical phenotype in L-amino acid decarboxylase deficiency. We review clinical features and outcome data in 11 affected patients, including 7 previously unreported cases. All had onset of the characteristic movement disorder by 6 months of age. The phenomenology of the movement disorder is identical to that previously reported, and includes intermittent oculogyric crises and limb dystonia, generalized athetosis, and impaired voluntary movement in all patients. Autonomic dysfunction is characterized by a significant impairment of sympathetic regulation of heart rate and blood pressure, as documented via detailed studies with spectral analysis techniques in two patients. Functional clinical outcomes as a group remain poor, in spite of a variety of attempted treatment interventions, with marked impairment in motor abilities as well as in speech and communication; however, outcome was quite variable from patient to patient and covered a broad spectrum of neurological disability. Much further work remains to identify and refine the best treatment options for patients with L-amino acid decarboxylase deficiency.