Tourette's syndrome is a neurological disorder that was first described by French neurologist Gilles de la Tourette in 1885. Tourette noticed in his practice a small group of mostly pediatric patients that had similar patterns of symptoms that presented consistently. He described the emerging syndrome as including involuntary motor movements with increased excitability, childhood onset, unusual vocalizations and likely genetic causes. These symptoms later became known as the disorder of childhood that bears his name. Since the original discovery, much as been learned about Tourette's and what might help treat it, with research historically examining the role of chemicals in the development of the disorder. Tourette's is considered a disorder of childhood because it has a childhood onset and many patients grow out of it by the time they reach adulthood.
What is Trimethylglycine?
Trimethylglycine, also called glycine, is a type of betaine that is manufactured by the body. Trimethylglycine's job in the body as a glycine betaine lies in breaking down other compounds that the body cannot use in high levels. A betaine is a naturally occurring substance found in sweet beets. In the human body it works with glycine in other functions. For instance, one of the compounds it breaks down is called homocysteine. Some people have a rare genetic condition where trimethylglycine does not do its job properly with this particular chemical, which leads to cardiovascular disease and other health problems. To discover if glycine can be helpful in Tourette's, it is necessary to look at its role in the disease process.
The Genetic Connection
One of the features of Tourette's syndrome is a pronounced startle reflex. Scientists thought that glycine receptors were involved in this symptom, so they examined whether there was a genetic reason for these malfunctioning receptors. In the late 1990s, many gene pathways were being discovered and tested. It was at this time that researchers in Great Britain conducted a study examining the link between glycine and Tourette's. Their data, which was published in the journal of Biological Psychiatry, revealed that glycine receptor genes involved in the startle reflex are not part of the genetic link of Tourette's syndrome. Since that study, scientists have switched to other genetic combinations to look at the inheritable nature of the disorder.
Glycine Levels in Tourette's Patients
Neurotransmitter and chemical imbalances are well documented in patients with Tourette's syndrome. To better understand how specific disturbances affect the disease, researchers in Poland examined levels of glycine, along with other chemicals, in the blood levels of Tourette's patients to look for relationships between chemical levels and factors such as age of onset, gender and severity of disease. Their results, which were published in 2010 in the Polish Journal of Neurology and Neurosurgery, showed that while the neurotransmitters GABA and glutamate had significant correlations with disease variables, glycine levels were not different between groups.
Glycine and Treatment
Research over the years that focused specifically on glycine has not produced results that can define the exact role of the chemical in Tourette's syndrome. However, it is well researched and documented that chemical imbalances, as well as dysfunctional metabolism of various chemicals, do contribute to the development of Tourette's. Perhaps as scientists continue to define the developmental path of the disorder, the role of trimethylglycine as a treatment agent will be better understood. At the time of this publication, however, trimethylglycine is not accepted or recognized as an appropriate treatment for Tourette's syndrome.
References
- "Treating Tourette Syndrome and Tic Disorders"; Douglas Woods, John Piacentini and John Walkup; 2007
- "Polish Journal of Neurology and Neurosurgery"; The Analysis of Selected Neurotransmitter Concentrations in Serum of Patients with Tourette Syndrome; P Janik et al.; March 2010
- "Biological Psychology"; Neuroreceptor Subunit Genes and the Genetic Susceptibility to Gilles de la Tourette Syndrome; PM Brett et al.; October 1997
