Pediatric Neurotransmitter Disease is an umbrella term for genetic disorders that affect the synthesis, metabolism and catabolism of neurotransmitters in children. Neurotransmitters are a group of chemical messengers that enable the communication between the neurons in the synaptic cleft. Neurotransmitters include the catecholamines (dopamine, norepinephrine, and epinephrine) and the indoleamines (serotonin and melatonin). They are chemical messengers, which mediate, amplify, or modulate synaptic transmission between neurons in the brain. Consequently, neurotransmitters are involved in central brain functions including control of movements and behavior, neuronal excitation and inhibition, the regulation of body temperature, pain threshold, memory, and a host of other processes. For biosynthesis of the biogenic amines dopamine and serotonin, tetrahydrobiopterin (BH4) is an essential cofactor. Folates are chemically similar to BH4 and play a key role in different processes off the central nervous system. Neurotransmitters include neuropeptides, purines, amino acids etc. Classification of neurotransmitter disorders is:
- Disorder of the tetrahydrobiopterin (BH4)
- Disorder in catecholamines and serotonin metabolism
- Disorder of serine and glycine metabolism
- Disorder of glutamate and GABA
- Disorder of folate deficiency
- Disorder of B6 metabolism
Inborn neurotransmitters related diseases belong to the rare metabolic, potentially treatable, genetic disorders, with clinical manifestation during childhood. The clinical phenotype is not characteristic but can mimic other neurological disorders. Some of the patients can be identified by newborn screening due to a hyperphenylalaninemia, while other will need quantitative determination of neurotransmitters or their metabolites in cerebrospinal fluid. Definitive diagnosis can be confirmed by molecular testing. Neurotransmitter disorders are important to recognize because early diagnosis and prompt therapeutic intervention seem to improve motor and cognitive outcome. Although therapy in some patients will not resolve all the symptoms, it will give better quality of life.