The Pediatric Neurotransmitter Disease Association is a recently established, nonprofit organization dedicated to helping children and families affected by diseases of neurotransmitter metabolism. Although the Association has many goals, its immediate mission is to increase awareness of these newly identified diseases. Recent studies have indicated that as many as ten to fifteen percent of children with encephalopathies (degenerative diseases of the brain) of unknown origin may actually have a pediatric neurotransmitter disease.
What are neurotransmitters and pediatric neurotransmitter diseases?
Neurotransmitters are chemicals that permit the passage of signals within the brain. A neurotransmitter can either excite or inhibit a nerve impulse. There are many neurotransmitters in the body, all of which work together to regulate motor coordination, behavior, temperature, pain mechanisms, and blood flow. The process by which our bodies make, use, and break down neurotransmitters is extremely complicated. When there is a disruption within this process, abnormalities can occur in any of their essential functions. A commonly known neurotransmitter is dopamine, a deficiency of which is associated with Parkinson's disease.
"Pediatric neurotransmitter diseases" is an umbrella term for genetic disorders that affect the functions of neurotransmitters, such as:
* Synthesis--The formation of compounds by combining simpler compounds or elements;
* Metabolism--The sum of chemical changes that occur in tissue; and
* Catabolism--The breaking down of complex chemical compounds into simple ones.
Some of the neurotransmitters involved in these disease groups include dopamine, norepinephrine, epinephrine, and gamma-aminobutyric acid (GABA). The diseases identified to date include: tyrosine hydroxylase deficiency (TH deficiency); aromatic L-amino acid decarboxylase deficiency (ALADD or AADC); GTP-1 cyclohydrolase deficiency (dopa-responsive dystonia); dihydropteridine reductase deficiency (DHPR); and succinic semialdehyde dehydrogenase deficiency (SSADH).
Common signs of these diseases include hypotonia (low muscle tone); rigidity; movement disorders (i.e., tremors or dystonia); oculogyric crises (abnormal eye movements); temperature instability; profuse sweating; absence of speech; and developmental delay. The presentation and severity depends on the particular neurotransmitter defect. Diagnosis of these neurotransmitter defects are made by one or more of the following tests:
* testing the cerebral spinal fluid for neurotransmitter metabolites and neopterin/tetrahydrobiopterin analysis;
* quantitative plasma catecholamines and serotonin levels;
* urine catecholamines;
* phenylalanine loading profile with and without tetrahydrobiopterin; and
* specific plasma or fibroblast enzymatic assay and molecular studies. Diagnosis of SSADH involves the following:
* testing the urine for the accumulation of 4-hydroxybutyric acid.
This test is typically not included in urine organic acids and must be specifically requested.
* mass spectrometric blood analysis.
Because many of the symptoms of PNDs are non-specific, diagnosis may be difficult. PNDs often seem to masquerade as other disorders, but will only show up when the proper tests are done. For example, doctors may suspect that a child has cerebral palsy because he or she exhibits symptoms, but an MRI of the brain shows nothing to support that. The PND Association's Medical and Scientific Advisory Board plans to release guidelines for testing in the future. Presently there are no cures for PNDs and response to treatment varies widely from no effect to dramatic improvement in symptoms. Proper diagnosis is essential.
The PND Association was founded and incorporated in 2000. The Association is composed of families who have children diagnosed with one of the diseases under the umbrella of PND and families with children who have suspected PNDs. …