What Your Genes Can (and Can't) Tell You About Your Health

The Promise and Reality of Genetic Health Insights

Headlines tout genetic testing as a crystal ball for health. The reality is more nuanced. While DNA provides valuable information, it's one piece of a complex puzzle that includes environment, lifestyle, and chance.

Understanding what genetics can and cannot predict helps you make informed decisions about testing and health management.

What Genetics CAN Tell You

Monogenic Conditions

Some diseases are caused by variants in a single gene with high penetrance (likelihood of developing the condition):

• Cystic fibrosis: CFTR gene variants
• Sickle cell disease: HBB gene variants
• Huntington's disease: HTT gene expansion
• BRCA1/2 variants: Significantly elevated breast/ovarian cancer risk

For these conditions, genetic testing provides relatively clear information, though even here, expression can vary.

Carrier Status

You can learn whether you carry recessive variants that could affect future children:

• Important for family planning decisions
• Identifies risk when both parents are carriers
• Standard screening covers dozens of conditions

Pharmacogenomics

Genetics influences drug metabolism:

• CYP2D6: Affects codeine, antidepressants, beta-blockers
• CYP2C19: Influences clopidogrel (Plavix) effectiveness
• VKORC1/CYP2C9: Warfarin dosing requirements
• *HLA-B57:01**: Abacavir hypersensitivity risk

This information can guide medication choices and dosing.

Ancestry and Population Risk

Certain conditions are more common in specific ancestries:

• Tay-Sachs in Ashkenazi Jewish populations
• Sickle cell trait in African descent populations
• Hemochromatosis in Northern European populations

What Genetics CANNOT Tell You

Most Common Diseases

The leading causes of death — heart disease, cancer, diabetes — are polygenic and multifactorial:

• Hundreds of genes contribute small effects
• Environmental factors often matter more than genetics
• Lifestyle choices significantly modify risk
• Prediction accuracy remains limited

A genetic risk score might indicate "1.5x average risk" for heart disease, but exercise, diet, and not smoking have far greater impact on outcomes.

Definitive Diagnoses

Genetic variants indicate probability, not certainty:

• Having a "risk variant" doesn't mean you'll develop the condition
• Not having known risk variants doesn't guarantee protection
• Most diseases result from complex gene-environment interactions

Timing or Severity

Even for conditions with genetic components:

• When (or if) disease will develop remains unpredictable
• How severe symptoms will be varies widely
• Response to treatment differs between individuals

Non-Genetic Health Factors

DNA cannot predict:

• Accidents and injuries
• Infectious disease exposure
• Environmental toxin effects
• Mental health from life experiences
• Social determinants of health

Understanding Genetic Risk

Absolute vs. Relative Risk

Headlines often emphasize relative risk increases:

• "50% increased risk" sounds alarming
• But 1.5% vs 1% is the absolute difference
• Context matters enormously

Polygenic Risk Scores

Modern approaches combine many variants:

• Sum small effects across thousands of SNPs
• Provide population-level risk estimates
• Have limited individual prediction accuracy
• Are being refined continuously

The "Missing Heritability" Problem

Twin studies suggest genetics explains significant disease variation, but identified variants account for much less:

• Rare variants remain undiscovered
• Gene-gene interactions are complex
• Epigenetics plays a role
• Current tools have limitations

Making Sense of Your Results

Questions to Ask

1. What is my absolute risk change?
2. How was this studied (which populations)?
3. What can I do about this information?
4. Should I consult a genetic counselor?
5. How confident is this finding?

When to Seek Professional Guidance

Consider genetic counseling for:

• High-penetrance variants (BRCA, Lynch syndrome)
• Family history of genetic conditions
• Reproductive planning decisions
• Unexpected or concerning findings
• Emotional support processing results

The Empowerment Perspective

Despite limitations, genetic information can:

• Motivate lifestyle improvements
• Guide screening and prevention
• Enable informed family planning
• Satisfy curiosity about ancestry
• Connect you with others sharing variants

The key is maintaining realistic expectations while using insights constructively.

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Genetiqo presents genetic information with appropriate context, uncertainty, and sources. Education, not diagnosis.