The Gist of Genetic Testing

By Dr. Sharon Norling, MD, MBA

How can a person with normal cholesterol who lives a healthy lifestyle suffer a heart attack at age 40? What makes some people more sensitive to allergens? Why are some individuals more prone to adverse drug reactions? Each individual person has a predetermined susceptibility to disease based on single nucleotide polymorphisms (SNPs). SNPs (pronounced “snips”) are DNA sequence variations that occur when a single nucleotide (A, T, C or G) in the genome sequence is altered.

Genome variations are differences in the sequence of DNA from one person to the next. Just as you can look at two individuals and see that they are different, you could do the same by looking at the genomes of two people with the right chemicals and laboratory equipment. Although more than 99 percent of human DNA sequences are the same across the population, variations in DNA sequence can have a major impact on how humans respond to disease, and environmental insults such as bacteria, viruses, toxins, chemicals, drugs and other therapies. The 0.1 percent is what has important implications for our health. Genomic instability can be avoided by receiving adequate nutrients, which are significantly above the Recommended Dietary Allowance (RDA).

We are now beginning to understand that DNA is not only responsible for the transfer of traits from parents to off-spring, but it also plays a dynamic, active role in their daily lives. When we exercise, genes in our muscles are suddenly awakened and make proteins that permit us to more effectively metabolize energy sources. When we are hungry, genes in our body are turned on that impact insulin levels. Certain food substances have been identified that turn genes on or off. Retinoic acid, zinc and other food substances are known to bind DNA.

SNPs are individual genetic variations in the genetic code associated with almost all diseases. SNPs alone do not cause disease rather they influence a person’s susceptibility to specific environmental factors that increase disease risk (including infections and chemical, physical and nutritional behavior triggers). SNPs lead to the unique responses of individuals that differentiate how they look and function, their predisposed immunity and how they will respond to therapy.

For the first time, physicians now have an assessment tool for determining individual susceptibility to potential disease. Specialty labs offer a unique line of predictive genomic diagnostic profiles for cardiovascular, detoxification, immune function, estrogen metabolism, neurological bone metabolism and inflammation. Testing for SNPs are relevant, prevalent and measurable. Most importantly, the effects of SNPs are modifiable. This means that the SNP can be modified by environmental and lifestyle factors such as nutrition, diet and toxic exposure.

These tests can help identify genetically based sensitivity to drugs, allergens and toxic chemicals. They can uncover genetic factors that trigger resistance to standard treatments. Have you ever asked yourself, “Why didn’t this work for me?” Physicians can now also understand hidden genetic factors affecting the severity of symptoms.

Customized treatments can:

1. Provide more precise, proactive health screening
2. Identify inherited risks within families
3. Gain deeper clinical insight into chronic, multi-factorial conditions

At no time in history has there been a more acute focus on health. Clearly there is a correlation between food, diet and disease. Nutritional genomics is a science studying the relationship between the human genome (all of the DNA a person possesses), nutrition and health. Diseases like obesity, cancer, diabetes and cardiovascular disease are polygenic diseases that arise from the dysfunction in a cascade of genes, not from a single mutated gene.

A number of genetic variations have been shown to increase susceptibility to dietrelated diseases. These include variants associated with Type 2 diabetes mellitus, obesity, cardiovascular diseases, some autoimmune diseases and cancers. According to internationally renowned nutrition researcher Dr. Jeffery Bland, everyone’s gene expression is determined by nutrition.

The food we eat is composed of complex mixtures of chemicals, many of which are biologically active. Vitamins, minerals and fatty acids act as dietary signals that manipulate our highly organized, tightly regulated DNA. Nutrigenomics seeks to understand if and how foods and plant extracts can affect the expression of genes in well-known disease pathways. Advances in nutrigenomics studies are the result of completion of the human genome project and new gene technologies. The ultimate goal of nutrigenetics is to provide personalized nutritional recommendations for individuals.

Hyperlipidemia is usually associated with atherosclerosis and coronary heart disease. Therapy includes lifestyle changes as alterations in the patient’s diet, physical activity and treatment with pharmaceuticals. However, individuals respond differently to the treatment. This is attributed to genetic variations within the population. Genetic variations in genes encoding for apolipoproteins, some enzymes and hormones can alter individual sensitivity to developing cardiovascular diseases. Some of these variants are susceptible to dietary intervention.

Are you plagued by a chronic condition that resists medical treatment? Testing can reveal whether you have genetic variations that make you more vulnerable to the harmful effects of toxins. They can also tell if you are less likely to respond well to certain drugs or nutrients.

Do you have a family history of a condition like heart disease or osteoporosis? When conditions “run in the family,” they often have a genetic component. Testing can show what specific genetic factors could pose a potential problem for you. For example, are your cholesterol levels more sensitive to a fatty diet than other people? Is your blood more likely to clot during long periods of inactivity? Do your bones properly use the nutrients they need? Is your blood pressure apt to be highly influenced by your salt intake? Once you have this information, you can develop a focused plan to “break the pattern”—and better prevent your family risks from turning into realities.

Do you take a very active role in optimizing your health? These tests can help you and your physician design a preventive program that works best for your body’s unique needs and health risks. The information can help you take aim at your most important targets years before symptoms even develop. Knowing your genetic “strong” and “weak” points allows you to devise a targeted, personal approach that increases your chances of remaining fit and active as you grow older.

Based on your genetic test results, your physician can work with you to develop a customized treatment plan. But the support doesn’t stop there. Testing is also available to monitor whether your personal healthcare strategy is having a positive impact on your genetic risks. These “functional assessments” give your physician a concrete way to evaluate how your body is responding to treatment. They also ensure that powerful environmental factors (hormones and nutrients) are in a state of optimal balance that minimizes your genetic health risks.

Seeing the results of your genetic test is like seeing the cards you’ve been dealt by nature. Once you know the cards, you can develop the most effective strategy to play out your hand. That means working with your healthcare provider to carefully develop a diet, lifestyle and supplement program that matches the unique health risks for your body. Genetic testing is a personal decision. Consult with your physician about your personal health history as well as your family history to determine if this option will give you important information for your health.

Current Tests Can:

1. Evaluate genetic variations (SNPs) that modulate blood pressure regulation, lipid balance, nutrient metabolism, inflammation, and oxidative stress
2. Evaluate SNPs associated with increased risk of impaired detoxification capacity especially when exposed to environmental toxins. It also identifies individuals potentially susceptible to adverse drug reactions
3. Evaluate genetic variations (SNPs) that modulate estrogen metabolism, coagulation, cardiovascular disease, and osteoporosis
4. Evaluate SNPs that modulate immune and inflammatory activity. These variations can reveal potential defects in immune system defense and stimulate mechanisms leading to chronic, overactive inflammatory responses
5. Evaluate SNPs that modulate methylation, glutathione conjugation, and oxidative protection relating to brain function
6. Evaluate SNPs that modulate the risk of osteoporosis and inflammation, including mechanisms affecting calcium and vitamin D3 metabolism.

---

Dr. Sharon Norling is the only physician in the U.S. to be nationally board certified in integrative medicine, medical acupuncture, functional medicine and OB/GYN. Her practice combines her extensive medical knowledge with the most recent advances in mind/body medicine. Her office is located at 32123 Lindero Canyon Road, Suite 210 in Westlake Village. Please call 818-707-WELL (9355).