Oromandibular Dystonia is a Prominent Feature in Patients with Aromatic L-Amino Acid Decarboxylase (AADC) Deficiency

Aromatic L-Amino acid decarboxylase (AADC) deficiency is a rare neurometabolic disorder due to a homozygous or compound heterozygous pathogenic variant of the DDC gene, resulting in low synthesis of the biogenic amines dopamine, serotonin, epinephrine, and norepinephrine. Most patients had severe expression of the disease with global developmental delay, early hypotonia, movement disorders such as oculogyric crises, tremor, and dystonia. Oromandibular dystonia (OMD) is rarely recognized in patients with AADC deficiency. The aim of this study was to describe OMD in detail in 4 patients with AADC deficiency. OMD occurred in isolated form or in association with oculogyric crises, increasing the difficulty in care patients during the crises. The main form of OMD was tongue dystonia associated with mouth opening dystonia. AADC deficiency must be included in the list of genetic causes of OMD.