New Genetic Test Offers Hope

This article originally appeared in February 2016.

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New Genetic Test Offers Hope

By Sharon McClellan Thomason

 

Folks in the Huntington’s disease community are quite accustomed to the bad news that a genetic test can bring; now there’s a genetic test that can actually bring GOOD news because it can help with the treatment of psychiatric symptoms. For me, this is even better than “good”—it’s EXCITING!

My son, Randy, has struggled with severe anxiety for almost a year. Severe like “can’t leave the house” severe. Like many other people who deal with psychiatric issues (depression, anxiety, psychosis, etc.), Randy has gone through a long, frustrating process of trial and error, trying, with his doctor, to find the right medications in the right dosage and the right combination. Typically, with psychotropic drugs, you try a medication for a couple of weeks, and if it doesn’t work, the doctor increases the dosage or tries a different drug altogether. (I went through five different antidepressants before finding, through trial and error, one that worked for me. That’s a lot of lost time when you’re dealing with issues that significantly impact your life!) After repeated med changes and changes in dosages made no difference, Randy’s doctor decided to do a pharmacogenomic test to try and determine what psychotropic drugs would be most effective for him.

The test is called GeneSight®, and according to the website (www.genesight.com), “The analysis is based on pharmacogenomics, the study of genomic factors that influence an individual’s response to medication treatments, manufacturers’ FDA-approved drug labels, peer-reviewed scientific and clinical publications, and proven drug pharmacology.” Approximately 210,000 patients have undergone GeneSight® testing, developed by Assurex Health in Mason, Ohio. The testing is based on “patented technology licensed from two world renowned medical centers, Mayo Clinic and Cincinnati Children’s Hospital Medical Center, who continue to be research collaborators.” It analyzes eight different genes as well as your metabolism.

The test started with two simple cheek swabs done right in the doctor’s office at a regular visit. She packaged them up according to directions and sent them off to the lab. Randy’s Medicare and Medicaid covered the cost of the test. It took a month for us to get the report.

Now here’s the really cool stuff! We went for Randy’s follow-up visit today, and his doctor went over the full report with us. The psychotropic test analyzes a person’s genetic makeup as it interacts with four categories of psychotropic medications: antidepressants, anxiolytics and hypnotics (anti-anxiety and sleep aids), antipsychotics, and mood stabilizers. It assesses a total of 55 different medications that fall into those categories and tells you and the doctor which medications can be used as directed, which ones have a moderate gene-drug interaction, and which ones have a significant gene-drug interaction. Drugs that have a significant interaction should be avoided; drugs that have a moderate interaction can be used, but with certain clinical considerations that are indicated on the report—lower or higher doses may be required; it may be difficult to predict dose adjustments due to conflicting variations in metabolism; the genotype may impact the drug’s mechanism of action and result in reduced efficacy; use of the drug may increase the risk of side effects; serum level may be too low in smokers; the FDA label may identify a potential gene-drug interaction for the medication.

Randy’s test revealed that he should NOT take Paxil® (an antidepressant/anti-anxiety drug) for three different reasons—lower doses may be required, reduced efficacy, and increased risk of side effects. Well, guess what? Randy has been taking Paxil® (paroxetine) for several months now, increasing the dose again and again, with him getting no better or even worse. The doctor wrote a new prescription today for Pristiq® (desvenlafaxine) instead. It’s one of the two drugs listed in the category of “Use as Directed.” In other words, this one SHOULD work as expected. There are 19 others listed in the middle category (Moderate Gene-Drug Interaction).

In the antipsychotic class, there are four drugs identified as having significant gene-drug interaction—these are the ones to avoid. In the past, Randy has been on two of these with terrible results, so I’m thinking this test is pretty accurate! In the class of mood stabilizers, he’s consistently been on Depakote® (valproic acid/divalproex), one of the three recommended for his genotype, and has done very well on it. Again, the test seems to be pretty accurate.

Randy’s doctor also did a second GeneSight® test on him—the MTHFR. This test analyzes one specific gene to predict how your body processes folic acid. If your body is unable to convert folic acid into its active form, this can cause folate deficiency, which can be important when treating depression, anxiety, cardiovascular disease, or when pregnant. Randy’s test showed that he has reduced folic acid conversion, resulting in moderately decreased serum folate levels. He also has moderately increased homocysteine levels, which is associated with low levels of Vitamins B6 and B12 and has been linked to increased risk for heart attacks, strokes, and renal disease. It can also interfere with creation of the brain’s “feel good” chemicals—dopamine, serotonin, and norepinephrine.

Because of the results on the MTHFR, Randy’s doctor has prescribed for him EnLyte®, which she described as “a medical food” in the form of a gelcap. Taken once a day, it is used in treating Alzheimer’s, mild cognitive impairment, vascular dementia, major depressive disorder, diabetic neuropathy, renal disease, and atherosclerosis. It’s basically a super multivitamin and must be prescribed by a physician. It includes three forms of folate, Vitamins B1, B2, B3, B6, and B12,CoEnzyme Q10, and Omega 3s, among other things. If it works like it’s supposed to, EnLyte® should help with Randy’s anxiety, depression, and cognition, and Florida Medicaid will cover it!

To say that I am excited and hopeful about all this is an understatement! In fact, I’m so excited that I’ve asked Randy’s doctor and a representative from Assurex Health to speak about GeneSight® at our Florida Symposium, October 8, 2016, at the Lodge at Wakulla Springs, and they’ve accepted the invitation. I believe that this is a major breakthrough, and it’s so important for our community to know that this kind of testing is available! I believe it will help physicians treat what 70% of people attending the FDA-PDUFA meeting in Silver Springs, Maryland, last September identified as the most troubling and problematic symptoms of HD. If it works as well as I hope it will, it can not only save precious time, something that folks in our community don’t have in abundance, but it can also give us more quality time!

As a side note, GeneSight® offers two other tests as well. Their Analgesic test analyzes gene interaction with 22 FDA-approved medications frequently prescribed for chronic pain, something that may be especially important for children with Juvenile Huntington’s disease. Their ADHD test analyzes gene interaction with eight different FDA-approved drugs for ADHD and narcolepsy.

Stay tuned for a report on what kind of results we get from the Psychotropic and MTHFR tests!