A Practitioner's Guide to Integrating Clinical Genomics

A patient walks into your office, not with a list of symptoms, but with a printout from a direct-to-consumer (DTC) genetic testing company. The report flags a variant associated with a serious condition, and the patient is, understandably, anxious. This scenario is no longer a hypothetical; it's a routine event in clinics across North America. The proliferation of DTC tests has created a patient population that is more engaged with their genetic information than ever before, but also more susceptible to misinformation and anxiety from unguided data.

Your role as a clinician is critical in bridging the gap between recreational genomics and clinical medicine. While many online forums and patient discussions revolve around which DTC company is 'best,' the more important conversation is about clinical utility. The challenge isn't just to debunk questionable findings from non-clinical tests but to recognize when a patient's history—or their DTC result—is the starting point for a necessary and clinically valid genetic investigation.

The Clinical-Grade Difference: Moving Beyond DTC Tests

The first step is to establish a clear distinction for yourself and your patient between two very different worlds: DTC testing and clinical diagnostic testing.

DTC tests are primarily designed for entertainment, ancestry, and wellness traits. They typically use a technology called SNP genotyping, which checks for specific, pre-selected single-nucleotide polymorphisms across the genome. While great for identifying if you have a variant associated with a distaste for cilantro, this method has severe limitations for medical diagnosis:

• Limited Scope: It only looks at specific 'dots' on the genome map, missing the vast majority of disease-causing variants.
• Lack of Confirmation: DTC labs are not typically CLIA-certified for diagnostic testing. Any medically significant finding from a DTC test must be confirmed in a clinical lab before any medical decisions are made.
• Minimal Interpretation: These reports lack the rigorous clinical interpretation and correlation with the patient's phenotype that is standard in a clinical report.

When a patient presents with a concerning DTC result or a personal/family history suggestive of a genetic condition, it's your cue to pivot the conversation toward clinical-grade testing. Clinical labs use technologies like Next-Generation Sequencing (NGS) and are held to stringent quality standards (CLIA/CAP). The entire process—from test selection to variant interpretation—is overseen by medical professionals and genetic experts.

Which Test, and When? A Framework for Clinical Decision-Making

Ordering a genetic test shouldn't be a fishing expedition. The most effective use of genomics in practice is hypothesis-driven, guided by the patient's clinical picture. Think of yourself as a detective building a case. What question are you trying to answer?

For the Diagnostic Odyssey

You have a patient with a complex, multi-system presentation that has defied diagnosis. Perhaps it's a child with developmental delay and dysmorphic features, or an adult with a progressive neurological disorder. Years of specialist visits and inconclusive tests have led nowhere.

• The Go-To Test: Whole Exome Sequencing (WES) or Whole Genome Sequencing (WGS).
• Why: WES sequences the protein-coding regions of all known genes (~1-2% of the genome, but where ~85% of known disease-causing mutations reside). WGS sequences the entire genome. These broad tests are powerful tools for identifying the single genetic cause of a rare, Mendelian disease. They are most effective when a specific diagnosis is elusive but a monogenic condition is suspected.

For Proactive Risk Assessment

A healthy 35-year-old woman reports that her mother and aunt were both diagnosed with breast cancer before age 50. She wants to know her own risk and what she can do about it.

• The Go-To Test: A targeted gene panel.
• Why: In this case, the clinical question is highly specific: does this patient have a pathogenic variant in a gene associated with Hereditary Breast and Ovarian Cancer (HBOC) syndrome or another cancer predisposition syndrome? A multi-gene panel that includes BRCA1, BRCA2, PALB2, CHEK2, and others is more efficient and cost-effective than sequencing an entire exome. The results can directly inform management, such as increased screening, risk-reducing medications, or prophylactic surgery.

For Optimizing Treatment

You are managing a patient with depression who has failed two different SSRIs due to side effects or lack of efficacy. Or perhaps you're about to start a patient on clopidogrel after a coronary stent placement.

• The Go-To Test: A pharmacogenomic (PGx) panel.
• Why: PGx testing analyzes genes—like CYP2D6, CYP2C19, and SLCO1B1—that influence how the body metabolizes and responds to drugs. A PGx report can help you personalize prescribing by identifying patients who may be ultra-rapid or poor metabolizers, guiding you to choose a different drug or adjust a dose from the start. This moves you away from a 'trial-and-error' approach and toward precision medicine.

Decoding the Report: A Primer on Variant Classification

Receiving a 20-page genetic test report can be daunting. The key is to focus on the 'Interpretation' or 'Summary' section, which is the culmination of the laboratory's analysis. Every identified variant is classified according to a standardized five-tier system, a framework established by the American College of Medical Genetics and Genomics (ACMG) and the Association for Molecular Pathology.

As laid out by Richards et al. in Genetics in Medicine (2015), the five tiers are:

1. Pathogenic: The variant is known to cause disease. This finding is clinically actionable.
2. Likely Pathogenic: There is very strong evidence (e.g., >90% certainty) that the variant causes disease. This finding is also considered clinically actionable.
3. Benign: The variant is known not to cause disease.
4. Likely Benign: Strong evidence suggests the variant does not cause disease.
5. Variant of Uncertain Significance (VUS): This is the most common and often most frustrating result. A VUS means that there is not enough evidence at this time to classify the variant as either pathogenic or benign. It does not mean the patient has a 'mystery' disease or that the variant is 'probably bad.' It is a statement about the limits of our current knowledge.

Crucially, clinical management decisions should not be based on a VUS. A VUS should not trigger prophylactic surgeries or enrollment in high-risk screening protocols. The proper response is to manage the patient based on their personal and family history, and to check for reclassification of the variant periodically as new evidence emerges.

The Conversation: Setting Expectations and Returning Results

How you talk to patients about genetic testing is as important as which test you order. The conversation must begin long before the results are in.

Before the Test: The Informed Consent Dialogue

Informed consent for genomic testing is a process, not a form. It's a critical opportunity to set realistic expectations. You need to prepare the patient for any possible outcome:

• A clear answer: Finding a pathogenic variant that explains their condition or confirms their risk.
• A non-answer: The test finds nothing, which doesn't rule out a genetic cause but simply means we couldn't find it with current technology.
• An uncertain answer: Receiving a VUS result and understanding its implications.
• An unexpected answer: Uncovering a secondary or incidental finding. This involves discussing the ACMG's list of medically actionable genes (e.g., cancer predisposition, cardiovascular risk genes) that labs may report back even if unrelated to the initial reason for testing. The patient should have the opportunity to opt out of receiving these specific findings, a decision that should be documented before ordering the test.

This pre-test counseling ensures the patient is an empowered partner in the process, ready for whatever the results may hold.

After the Test: Communicating the Results

When returning results, context is everything. A pathogenic variant in BRCA1 means something very different for a 25-year-old with no personal history of cancer than for a 60-year-old currently undergoing treatment.

• For a Pathogenic Result: The conversation should be direct but empathetic. Immediately pivot to the 'what's next'—the concrete management plan. This includes referral to appropriate specialists (e.g., high-risk oncology, cardiology), discussion of screening and prevention options, and emphasizing the importance of cascade testing for at-risk family members.

• For a VUS Result: Reiterate that this is a result of 'uncertainty.' Emphasize that you will continue to manage them based on their clinical picture and family history. Explain that labs and databases like ClinVar are constantly being updated, and this variant may be reclassified in the future. Frame it as an ongoing question, not a final answer.

Integrating genomics into your practice is a journey. It requires a commitment to continuous learning and a willingness to embrace a new dimension of patient data. But by grounding your approach in strong clinical indications, leveraging the expertise of clinical labs and genetic counselors, and mastering the art of the patient conversation, you can harness the power of the genome to provide more precise, proactive, and personalized care.

At BioGenetic, we are committed to being your partner in this process. We provide not just data, but clinically-interpreted, actionable insights, supported by a team of experts ready to help you and your patients navigate the complexities of genomic medicine.

Thinking of integrating genetic testing into your practice or looking for a more collaborative lab partner? Learn more about our solutions for healthcare professionals.

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Sincerely,

Equipo BioGenetic

References

Richards, S., Aziz, N., Bale, S., et al. (2015). Standards and guidelines for the interpretation of sequence variants: a joint consensus recommendation of the American College of Medical Genetics and Genomics and the Association for Molecular Pathology. Genetics in Medicine, 17(5), 405–424.

Kalia, S. S., Adelman, K., Bale, S. J., et al. (2017). Recommendations for reporting of secondary findings in clinical exome and genome sequencing, 2016 update (ACMG SF v2.0): a policy statement of the American College of Medical Genetics and Genomics. Genetics in Medicine, 19(2), 249–255.