Conclusions: Dopamine agnonists can give rise to episodes of hypglycaemia in patients with AADC-deficiency. Background: AADC deficiency is a rare autosomal recessive metabolic disorder, characterized by the lack of decarboxylation of the aromatic amino acids, L-dopa and 5-hydroxytryptophan, causing a dopamine, epinephrine, norepinephrine, and serotonine (metabolites) deficiency. Less than 100 cases have been diagnosed throughout the world. Methods: We report the case of a 7-month-old white male who was diagnosed with Aromatic L-Amino Acid Decarboxylase (AADC) Deficiency. This diagnosis was based on CSF monamine neurotransmitter analysis and corroborated by enzymatic and genetic testing. Results: The proband was breech with neonatal hypotonia and has not met any developmental milestones. He presented for evaluation paroxysmal events which had been occurring for three months. The events are characterized by repetitive dyskinetic chewing motions without loss of consciousness. In addition to these events, the patient also had intermittent dystonic opisthotonic posturing, diaphoresis, occulogyric crises and sleep difficulties. He was tried on multiple antiepileptic medications which exacerbated his symptoms. Treatment with COMT inhibitor and Bromocriptine were not tolerated. The dystonic movements and sleep difficulties improved greatly with Lioresal and pyridoxine. Other symptoms such as diaphoresis are not Conclusion: Paroxysmal dyskinesia with stereotypic chewing and sleep difficulties due to AADC improved with Lioresal. The diagnostics of neurotransmitter disorders is almost exclusively based on the quantitative determination of the neurotransmitters or their metabolites in cerebrospinal fluid (CSF). The implementation of neurotransmitter analysis in clinical praxis is necessary for early diagnosis and treatment. Material and Methods: Neurotransmitter metabolites in CSF were analyzed in 82 children (at the age 1 months to 17 years) with clinical suspicion for neurometabolic disorders using HPLC with electrochemical detection. Results: The CSF level of homovanillic acid (HVA) was markedly decreased in three children (64, 79 and 94 nmol/l) in comparison to age related controls (lower limit 218-450). Neurological finding including severe psychomotor retardation, quadruspasticity and microcephaly accompanied with marked dystonia, excessive sweating in the first patient was compatible with the diagnosis of tyrosine hydroxylase (TH) deficiency (type B phenotype) and subsequent molecular analysis revealed two novel heterozygous mutations c.636A>C and c.1124 G>C in the TH gene. The treatment with L-DOPA/carbidopa resulted in the improvement of dystonia. MRI studies in two other patients with microcephaly revealed postischemic brain damage, therefore secondary HVA deficit was considered in these children. Introduction: Tyrosine hydroxylase deficiency includes two clinical phenotypes: an infantile progressive hypokinetic-rigid syndrome with dystonia (Type A) and a neonatal complex encephalopathy (Type B). Case Report We have revised video recording, that were obtained in a 15 years follow-up, of a male patient with a THD-type B. In the first months of life he had a truncal hypotonia, a severe hypokinesia and a reduced facial mimicry. Oculogyric crises and episodes of stupor were reported. THD was diagnosed when he was 18 months old according to CSF biogenic amine alterations and pathogenic mutation on TH gene. In the following years he suffered from generalized choreoathetosis and daily on-off phenomena. He walked unsupported at 11 years old while mental and language functions remained severely impaired. Different dopamine-mimetic drugs (including L-dopa-carbidopa, pramipexole, selegiline, entacapone, tolcapone, pyridoxine and rotigotine) were used. At the beginning he was a slow responder to pharmacological treatments. After the school age his response improved, despite fluctuations of symptoms and drugs-induced side effects (i.e. severe dyskinesia under pramipexole). Conclusions: Our experience demonstrates that the course of motor disorders in Type B variant requires a very slow increase of dopaminergic therapy. Mental retardation remains the main problems in these subjects. Background: Tyrosine hydroxylase (TH) deficiency is an IEM of neurotransmission with variable clinical presentation and L-dopa response, in which mechanisms of synaptic communication have not been described.