What are some theoretical ways that many neurological diseases could be cured? (i.e. ADHD, OCD, Tourette's Syndrome, Depression)

A genetic marker is a DNA sequence with a known physical location on a chromosome. DNA segments close to each other on a chromosome tend to be inherited together. Genetic markers are used to track the inheritance of a nearby gene that has not yet been identified, but whose approximate location is known.

ADHD (attention deficit hyperactivity disorder) runs in families. Anywhere from one-third to one-half of parents with ADHD will have a child with the disorder? There are genetic characteristics that seem to be passed down. If a parent has ADHD, a child has more than a 50% chance of having it. Researchers have been unable to identify a single cause for ADHD. A combination of genes, environmental factors, and possibly diet seem to influence the likelihood of a person developing ADHD. Researchers have found that a genetic variant on the latrophilin 3 gene (LPHN3) is associated with ADHD in several different populations. Previous studies have also shown that this gene plays a role in how people respond to the stimulant medications often used to treat the childhood behavioural disorder. ADHD is still incompletely understood, results from family, twin and adoption studies, as well as molecular genetic studies consistently indicate the strong genetic influence on ADHD with estimated heritability ranging from 75% to 91%. In the next few years, the number of genetic studies of ADHD is expected to keep increasing especially with the development of new technologies.

Experts say OCD affects an estimated 1 to 2 percent of the U.S. Population. A genetic marker that may be associated with the development of obsessive-compulsive disorder (OCD), whose causes and mechanisms are among the least understood among mental illnesses, has been identified by researchers. A significant association (on chromosome 9) was identified in OCD patients near a gene called protein tyrosine phosphokinase (PTPRD). Moreover, some cases of attention-deficit hyperactivity disorder (ADHD) have been associated with the gene (PTPRD), and OCD and ADHD have some symptoms in common. The gene also works with another gene family, SLITRK, which has also been associated with OCD in animals.

A variety of genetic and environmental factors likely play a role in causing Tourette syndrome. A small number of people with Tourette syndrome have been found to have mutations involving the SLITRK1 gene. Brain researchers say they have confirmed for the first time that a rare genetic mutation can cause some cases of Tourette syndrome, with the fault disrupting production of histamine in the brain. The authors will be investigating treatment of Tourette syndrome by drugs that target histamine receptors in the brain. Histamine is an organic nitrogenous compound involved in local immune responses, as well as regulating physiological function in the gut and acting as a neurotransmitter for the brain, spinal cord, and uterus. The specific gene in this study is called HDC (the histidine decarboxylase gene), which the researchers previously found to be mutated in a family that had nine members with Tourette syndrome.

For depression, researchers found evidence that by removing from the cohort people who have experienced major life adversities, they can unveil genetic factors associated with depression whose physiological effects may be in common to those caused by adversities. This can help researchers pin down the biological mechanisms involved in depression. A study in Nature revealed the first two genetic regions that are associated with an increased risk for developing major depression. The findings of this new study take the research a step further by factoring in people's life histories and discovered three additional genetic markers that only have a significant effect for people who have not experienced extreme adversity. These genes have functions in mitochondrial function and metabolism, so one potential direction for future research is to try and understand the link between depression and metabolism. In the future it is hoped that research such as this will help to identify high-risk individuals for early intervention and personalized medicine.

One way to help the above problems is to use gene therapy, which involves altering the genes inside your body's cells in an effort to treat or stop disease. Researchers are investigating replacing mutated genes or mutated genes that cause disease could be turned off so that they no longer promote disease, or healthy genes that help prevent disease could be turned on so that they could inhibit the disease. Along with genes, environment and diet must be looked at for each neurological disease.

Reference: Ron Kolinie