Originally published in The Ottawa Citizen March 24, 2005

If your doctor offered the option of a blood test to determine what diseases your child will develop in their lifetime, what would you do? This option is soon to be a reality.

A report published in the January 2005 issue of the American Journal of Medical Genetics revealed that bipolar disorder and schizophrenia can now be diagnosed through a blood test using the science of genomics.

Genomics is the study of the genes that are being expressed (or actively working) in our cells. This field has developed from the human genome project; the mapping of the 30,000 human genes.

All our cells contain these genes, but not all are expressed. These genes provide the blueprints to produce proteins and other products for normal physiological function. These proteins can also tell us if there are specific diseases present.

Imagine if you were sent on a scouting mission to describe your neighbourhood. Each neighbourhood has its own unique landmarks and terrain with a variety of dwellings, gardens and roads. Your report is influenced by what you have seen, smelled and heard.

The body has a similar scout or sentinel called the white blood cell. A Canadian company, ChondroGene, has developed a diagnostic test that uses a process called the Sentinel Principle.

Dr. Wayne K. Marshall, president and CEO of ChondroGene, explained that when this sentinel cell passes through a diseased neighbourhood in the body, it will be influenced by the environment within and around the diseased tissue. Certain genes present within the white blood cell (RNA or ribonucleic acid) will turn on; in effect telling the story of where it has been. This story is also known as a biomarker, a unique molecular genetic profile of the diseased cells.

Dr. Marshall says this process can also detect early stages and the severity of other diseases, including arthritis, by using gene chips, a microscope-like slide that has thousands of genes imprinted onto it.

The RNA is extracted from the sentinel cell and placed on the gene chip. Through a sophisticated reaction process, the genes present in the RNA will attach themselves to specific genes on the chip. A computer program will read this chip and identify the disease it represents; each disease has a unique molecular signature or pattern.

Ongoing studies have looked at more than 7,000 patients and identified about 40 disease processes at various stages of development. Dr. Marshall says there are very distinct molecular signatures or gene combinations for the 40 diseases studied so far. To date, these diseases are represented by a combination of hundreds of genes.

Dr. Marshall states the next step is to look at reducing the number of key identifying genes to five or 10 to improve the early detection process.

The Sentinel Principle is being applied to four main areas: cancer, central nervous system disorders and psychiatric disorders, cardiovascular disease and arthritis. Many of these diseases do not have good diagnostic methods for early detection and treatment. The diagnosis of bipolar disorder and schizophrenia is wholly dependent on clinical signs and symptoms.

“The biggest problem we have is that we are not picking up these diseases until they are well established, and then the treatment is much more difficult and may not be as effective,” Dr. Marshall explained.

Preliminary data suggests that some of these diseases can be diagnosed prior to their expression. The genetic biomarkers of these diseases seem to be present even before the occurrence of disease symptoms.

Science fiction is becoming science fact. “There are several areas where we are focusing very aggressively right now, particularly in some cancers,” Dr. Marshall said.

“I believe that within the next 18 to 36 months we will have tests at least in a couple of disease areas where we can start to apply this principle. The beauty of this is that it is a principle that can be applied across any disease area.”

From a medical standpoint, this technology has the potential to help millions of people and reduce the burden on our health care system. The question is how others will use it.

Insurance companies may insist on this test and deny or restrict coverage on the basis of the client’s biomarkers. The information could prevent employment opportunities. Safeguarding this information would be paramount.

Nevertheless, this technology heralds a scientific avenue of new medical technologies that will explode into the mainstream of diagnosis and treatment. The intellectual steps taken to get here are inspiring.

---

© Dr. Barry Dworkin 2005