Aromatic l‐amino acid decarboxylase deficiency associated with epilepsy mimicking non‐epileptic involuntary movements

Abstract

Aromatic l‐amino acid decarboxylase (AADC) deficiency is a rare inborn error of neurotransmitter biosynthesis that leads to a combined deficiency of catecholamines and serotonin and is characterized by global developmental delay, involuntary movements, and autonomic dysfunction. We report the case of an 11‐year‐old male patient with AADC deficiency who also had epileptic spasms and generalized tonic seizures with asymmetrical features, in addition to frequent involuntary non‐epileptic movements. The clinical manifestation of the epileptic attacks apparently resembled that of non‐epileptic attacks. It was difficult to differentiate between both attacks without the help of an ictal electroencephalographic study. The epileptic attacks were finally controlled by appropriate antiepileptic drugs. Because an association with epileptic seizures is uncommon in AADC deficiency, some cases may have been regarded as involuntary non‐epileptic movements. This indicates that the differentiation of epileptic attacks from non‐epileptic ones is indispensable for the adequate treatment of patients with AADC deficiency.

Aromatic l‐amino acid decarboxylase deficiency: clinical features, drug therapy and follow‐up

“…There are only few reported AADC patient with epileptic seizures (Ito et al 2008;Swoboda et al 2003). More often the paroxysmal movement disorder in AADC deficiency is misinterpreted as epileptic seizures.…”

Consensus guideline for the diagnosis and treatment of aromatic l-amino acid decarboxylase (AADC) deficiency

“…Epileptic seizures were described in 9 patients [2, 7, 22, 38–40]. Behavioral problems can be a great burden to patients and caregivers but are not well defined in the literature.…”

“…In the remaining cases, described abnormalities were heterogeneous, including: diffuse mild cerebral atrophy [2, 38], cortical atrophy [41], reduced prefrontal volume with normal myelination and normal basal ganglia [36], focal demyelination changes over bilateral frontal and left parietal area [4], leukomalacia [4], degenerative changes of white matter, thinning of corpus callosum, prominent ventricular bodies, leukodystrophy-like patterns, and hypomyelination [2]. Since there is no specific MRI pattern, imaging is not helpful in the diagnosis of AADCD.…”

Aromatic L-Amino acid decarboxylase deficiency: A new case from Turkey with a novel mutation

“…MRI findings that could be seen in this disorder were atrophy, reduced myelination, and white matter changes. [567] The first step in reaching the diagnosis is the investigation of neurotransmitters in CSF. In addition to typical pattern with a distinct reduction of HVA, 5-HIAA, and 3-OMD as well as an elevation of levo-dopa and 5-hydroxytryptophan; endocrinological findings could be found, for example, elevated prolactin, hypoglycemia, and growth hormone deficiency.…”