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How APOE and rs405509 relate to concussion risk and recovery

A concussion is a mild traumatic brain injury that occurs when a blow or jolt to the head causes the brain to move rapidly within the skull. Common symptoms include headache, dizziness, confusion, memory problems, sleep disturbances, and balance issues. Recovery varies between people and can be influenced by age, prior injuries, overall health, and genetics. One gene that has been studied in relation to brain injury is APOE, which plays a central role in fat transport and metabolism in the brain and in repairing damaged neurons.

The single nucleotide polymorphism (SNP) rs405509 near APOE can affect how APOE functions. Different genotypes at rs405509 are sometimes described in terms of "effect alleles" that may modestly influence concussion susceptibility or recovery. Regardless of genotype, lifestyle choices and early, appropriate medical care have a large impact on outcomes after head injury.

Key things to remember

  • Genetics may influence vulnerability and recovery but do not determine destiny.
  • Preventing head impacts, recognizing symptoms early, and following medical guidance after a suspected concussion are essential.
  • Diet, sleep, hydration, exercise, and controlled return-to-activity plans support brain health and recovery.
  • PlexusDx provides educational genetic information and does not provide medical advice. Always consult your healthcare provider for diagnosis and treatment.

Genetic interpretation (expand for the genotype that matches you)

2 effect alleles — TT genotype

If your genotype at rs405509 is TT (two copies of the effect allele), research suggests you may have a slightly higher susceptibility to concussion and a potentially different recovery profile compared with people without the effect allele. APOE influences lipid transport and repair processes in the brain, and variation at this site may alter those processes after injury.

What this means for you:

  • Take extra precautions to avoid repeated head impacts, especially in contact sports or high-risk activities.
  • Report symptoms promptly and follow a medically supervised return-to-play or return-to-activity plan after any head injury.
  • Focus on proactive brain health strategies to support resilience and recovery.
1 effect allele — GT genotype

If your genotype at rs405509 is GT (one copy of the effect allele), you may have a modestly increased influence on how your brain responds to injury compared with people who carry no effect allele. This does not mean you will definitely have problems after a concussion; it means genetics may be one of several factors that influence outcome.

What this means for you:

  • Practice good head injury prevention and report any symptoms without delay.
  • Adopt brain-supportive lifestyle habits to reduce risk and aid recovery if an injury occurs.
  • Work with your healthcare team for individualized monitoring after head trauma.
0 effect alleles — GG genotype

If your genotype at rs405509 is GG (two copies of the non-effect allele), your APOE-related concussion risk is considered typical compared with general population baselines. Your APOE function is likely in the common range for lipid transport and neuronal repair.

What this means for you:

  • You do not carry the rs405509 variation that has been associated with altered concussion susceptibility, but that does not eliminate concussion risk.
  • Continue standard prevention, symptom monitoring, and brain-health practices to minimize risk and support recovery if needed.
  • Follow medical guidance after any suspected head injury.

Practical strategies to support brain health and reduce concussion risk

Dietary recommendations

  • Increase intake of omega-3 fatty acids — especially EPA and DHA — found in fatty fish (salmon, sardines, mackerel) or high-quality supplements. Omega-3s support neuronal membrane integrity and reduce inflammation.
  • Prioritize antioxidant-rich foods — colorful fruits and vegetables, berries, leafy greens, nuts, and seeds — to help limit oxidative stress after injury.
  • Include anti-inflammatory foods — olive oil, turmeric, ginger, and foods high in polyphenols — and limit highly processed foods, excess sugar, and trans fats.
  • Maintain consistent protein intake to support tissue repair and recovery.

Supplements to consider

Supplements can be helpful but should be discussed with your healthcare provider before starting. Potential options include:

  • High-quality fish oil providing EPA/DHA, at doses advised by a clinician.
  • Vitamin D if you are deficient, since optimal vitamin D supports overall brain and immune health.
  • Multivitamin or targeted B vitamins to support energy metabolism and neurological function if dietary intake is inadequate.
  • Curcumin or other anti-inflammatory phytonutrients, used under supervision due to interactions and absorption considerations.

Lifestyle recommendations

  • Sleep: Aim for consistent, restorative sleep (7 to 9 hours for adults). Sleep is critical for brain repair and cognitive recovery after injury.
  • Hydration: Even mild dehydration can worsen headache and cognitive symptoms. Drink fluids throughout the day, especially around physical activity.
  • Exercise: Regular aerobic exercise supports brain health when not acutely injured. After a concussion, follow a graded, clinician-guided return-to-exercise plan.
  • Injury prevention: Use appropriate protective equipment, practice safe techniques in sports, and reduce fall risk at home and work.
  • Mental health: Address stress, anxiety, and mood symptoms promptly, as they can impact recovery and symptom burden.

Monitoring and tests to discuss with your provider

  • Clinical concussion assessment and baseline neurocognitive testing if you participate in contact sports.
  • Follow-up evaluations for persistent or worsening symptoms including balance testing and cognitive assessments.
  • Blood tests as clinically indicated to check vitamin D, basic metabolic panel, thyroid function, or other contributors to fatigue and cognitive symptoms.

After a head injury — steps to take

  • Stop the activity and seek immediate medical attention if you suspect a concussion.
  • Rest initially, then follow a gradual, clinician-directed increase in cognitive and physical activity as symptoms improve.
  • Report any new or worsening symptoms to your healthcare provider quickly.
  • Keep a symptom diary to track progress and identify triggers that worsen symptoms.

Limitations and what this information means for you

The rs405509 genotype is one small part of a complex picture. Having an effect allele may slightly influence concussion susceptibility or recovery in some studies, but it does not predict outcomes with certainty. Environmental factors, prior injuries, age, overall health, and how quickly you receive appropriate care are typically more influential.

PlexusDx provides educational genetic information to help you understand possible predispositions and practical steps you can take to support brain health. This information is not medical advice. Always consult your healthcare provider for diagnosis, individualized recommendations, and any decisions about tests, treatments, or supplements.