Navigenics - Considerations and caveats

The Navigenics Health Compass is not a diagnostic test but rather establishes genetic predisposition to common conditions, so prevention or early detection may be possible. Here are some points to consider as you assess individuals at elevated risk for the conditions we cover.

Abdominal aneurysm

Note that the data from the genome study indicate that the genetic variant leads to increased susceptibility for developing an aneurysm, rather than an increased risk of rapid progression or rupture.

Alzheimer's disease

The Navigenics Health Compass addresses late-onset Alzheimer's disease, not early onset. Individuals who have relatives diagnosed with Alzheimer's before age 60 may be at greater risk than we have estimated and should consult a Genetic Counselor.

Atrial fibrillation

In view of an increased tendency to atrial fibrillation, it may be worthwhile to readdress with your patient any symptoms not previously categorized: palpitations, syncope, etc. Reviewing avoidance of precipitating factors such as stimulants and decongestants also may be prudent.

Breast cancer

Pending evaluation and a detailed family history, it may be appropriate to consider early breast screening. Also note that our panel does not cover certain important, uncommon single-gene mutations that can cause breast cancer, such as the BRCA1 and BRCA2 genes associated with Hereditary Breast and Ovarian Cancer Syndrome (HBOC). If individuals can answer "yes" to any of these questions they may be at greater risk than we have estimated and should discuss BRCA testing with you or a Genetic Counselor:

• Have you or anyone in your family had breast cancer before age 50, cancer in both breasts at any age or ovarian cancer at any age?
• Have two or more close relatives on the same side of your family (maternal or paternal) had breast or ovarian cancer, or has one relative had both?
• Do you have any male relatives with breast cancer?
• Do you have Ashkenazi (Eastern European) Jewish ancestry and at least one family member with breast or ovarian cancer at any age?
• Do you have any relatives with an identified genetic mutation that increases their risk for cancer?

Celiac disease

Symptoms of celiac disease may be subtle and mimic irritable colon. If the individual complains of symptoms suggestive of celiac disease, confirmatory tests such as gliadin antibody, endomysial antibody and anti tissue transglutaminase may be indicated. If appropriate, a referral to a gastroenterologist might be considered.

Colon cancer

Pending evaluation and a detailed family history, it may be appropriate to consider early colon screening. Also note that our panel does not cover certain important, uncommon single-gene mutations that can cause colon cancer (syndromes such as HNPCC or FAP). If individuals can answer "yes" to any of these questions, they may be at greater risk than we have estimated and should discuss further testing with you or a Genetic Counselor:

• Have you or anyone in your family had colon cancer before the age of 50, or multiple colon polyps?
• Have two or more close relatives on the same side of your family (maternal or paternal) had colon, uterine or ovarian cancer, or has one relative had more than one of these cancers?
• Do you have Ashkenazi (Eastern European) Jewish ancestry and at least one family member with colon cancer at any age?
• Do you have any relatives with an identified genetic mutation that increases their risk for cancer?

Crohn's disease

Symptoms, if any, may be subtle and mimic irritable colon. Perhaps readdress complaints previously passed over.

Diabetes, type 2

A baseline Hemoglobin A1c or fasting glucose may be appropriate for future reference.

Glaucoma

Our panel screens for genetic markers that increase the risk for a subtype of glaucoma known as exfoliation glaucoma. Consider obtaining a baseline eye exam with visual fields.

Graves' disease

You might be attuned to — and make your patient aware of — unusual presentations such as diarrhea, fatigue and muscle weakness.

Heart attack

Consider readdressing borderline lipids or ordering a specialized lipid panel including lipid subclasses.

Lung cancer

The available data indicate that these results apply primarily to current and former smokers.  It’s difficult to evaluate non-smokers as they are affected so infrequently. One study, though, did show a modest association in non-smokers. So even non-smokers should be considered to be at some increased risk if they have the variant for which we test.

Lupus

Our panel screens for genetic markers that increase the risk of developing systemic lupus erythematosus. Consider readdressing any complaints that might be related to lupus in view of a possible increased tendency.

Macular degeneration

A baseline eye exam may be appropriate. Also, instructing your patient in the use of the Amsler Grid to detect degeneration should be considered.

Multiple sclerosis

Consider neurological referral for even subtle symptoms, because early treatment with disease-modifying medications can make a difference.

Obesity

Even if your patient is not obese, and there is no strong family history of such, it may not be unreasonable to remind your patient that caloric needs decrease with age, and the prevalence of obesity increases with age.

Osteoarthritis

Even if an individual has no symptoms, it may still be reasonable to encourage appropriate lifestyle changes like weight reduction and reducing repeated joint trauma.

Prostate cancer

Pending evaluation and a detailed family history, it may be appropriate to consider early prostate cancer screening by serum PSA testing and digital rectal examination.

Psoriasis

While classical patches of psoriasis are fairly obvious, consider checking your patient periodically for lesions in less common places, such as the intergluteal region, that may present differently. Also be alert to nail changes and arthritic symptoms that may suggest psoriatic arthritis, which has a better prognosis if treated early.

Restless legs syndrome

Many patients are concerned that they may have RLS, particularly since there are treatments for this condition. The Navigenics Health Compass may help you decide.

Rheumatoid arthritis

Consider reassessing even mild joint complaints or questioning your patient about extra-articular rheumatoid symptoms. A baseline sedimentation rate may be helpful for future comparison.