HSA | FSA CARDS ARE NOW ACCEPTED

Last reviewed: May 12, 2026 Last updated: May 12, 2026

Written by: Jay Hastings , CEO of PlexusDx

Jay Hastings is the CEO of PlexusDx, a precision health company focused on genetic testing, blood biomarker insights, and personalized wellness recommendations. He has more than 20 years of experience across healthcare innovation, genomics, laboratory operations, healthcare investing, and strategic finance. His work has included scaling healthcare startups, leading CLIA lab integrations, and helping expand consumer access to precision health tools.

Medically reviewed by: Jayden Lee, PharmD, EMBA

Jayden Lee, PharmD, EMBA, is the PlexusDx Medical Science Liaison with a PharmD and MBA specializing in pharmacogenomics and clinical product development, with a proven ability to bridge the gap between genomic research and practical patient outcomes. Dr. Lee has more than 10 years of professional experience in clinical pharmacy, academia, and research.

Understanding CHDH and the rs12676 Variant

The CHDH gene makes an enzyme that converts choline into betaine (trimethylglycine or TMG). Betaine supports the methylation cycle by helping convert homocysteine into methionine. Proper CHDH function is important for liver and muscle health, cell membrane integrity, and overall methylation balance. Variations in CHDH activity can change how efficiently choline is used, increasing risk of choline deficiency when dietary intake is low or with high alcohol use. That shift can reduce phosphatidylcholine production and affect cell membranes.

How this affects health

When CHDH activity is reduced, your body may rely more on alternate pathways to handle methylation and phosphatidylcholine synthesis. This can increase demand for dietary choline, betaine, folate, vitamin B12, and other cofactors. Over time, inefficient methylation can contribute to elevated homocysteine, altered liver fat metabolism, and potential impacts on muscle function. Lifestyle and diet strongly influence whether a genetic change translates into measurable health effects.

Genetic Interpretation for rs12676

Two effect alleles (AA)

If your genotype is AA, you carry two copies of the effect allele. This configuration may reduce CHDH enzyme activity or efficiency. Reduced activity can impair the conversion of choline to betaine, increasing reliance on dietary choline and other methyl donors. Potential consequences include a higher chance of methylation imbalance, elevated homocysteine, and reduced phosphatidylcholine production under stressors such as low dietary choline or alcohol use. Consider proactive dietary and lifestyle steps to support methylation and liver health.

One effect allele (AC)

If your genotype is AC, you carry one copy of the effect allele. This may cause a partial reduction in CHDH function. Enzyme activity is generally better than with two effect alleles but may still be suboptimal under stressors like low choline intake, pregnancy, or high alcohol consumption. A balanced diet with adequate choline and supportive B vitamins can help maintain normal methylation and cell membrane health.

Zero effect alleles (CC)

If your genotype is CC, you carry two copies of the non-effect allele. This genotype is typically associated with normal CHDH activity. Your body is likely able to process choline into betaine efficiently, so the baseline risk of methylation imbalance from this gene alone is lower. Standard dietary recommendations for choline and B vitamins remain relevant for overall health.

Diet Recommendations

  • Prioritize choline-rich foods: eggs (especially yolks), beef liver, poultry, fish, shellfish, and dairy. Plant sources include soybeans, quinoa, and cruciferous vegetables but contain less choline per serving.
  • Include betaine-containing foods: beets, spinach, quinoa, wheat bran, and shellfish supply natural betaine to support methylation.
  • Support methylation with folate and B12: eat leafy greens, legumes, fortified grains, and animal products or consider methylfolate and B12-containing foods if you follow a restricted diet.
  • Omega-3 fats: fatty fish, flaxseed, walnuts, and algae support cell membrane integrity and liver health alongside choline.
  • Limit excessive alcohol: alcohol increases choline demand and can worsen effects of reduced CHDH activity.

Supplement Suggestions

Consider supplements if dietary intake is insufficient, you have increased demand (pregnancy, heavy exercise, alcohol exposure), or if blood tests suggest imbalance. Always review supplements with your healthcare provider.

  • Choline: choline bitartrate or alpha-GPC to raise available choline. Phosphatidylcholine may better support cell membranes.
  • Betaine (TMG): can directly support homocysteine remethylation when CHDH conversion is limited.
  • Methyl donor B vitamins: active forms of folate (5-MTHF), vitamin B12 (methylcobalamin), vitamin B6 (pyridoxal-5-phosphate) to support the methionine cycle.
  • Multivitamin with adequate B vitamins and antioxidants to support liver function.

Lifestyle Recommendations

  • Moderate alcohol intake or abstain if possible, since alcohol increases choline demand and can impair liver methylation.
  • Maintain a balanced protein intake to supply amino acids used in methylation and liver repair.
  • Pursue regular physical activity to support muscle and liver health; avoid extreme low-calorie diets that reduce nutrient availability.
  • Manage body weight and metabolic health to reduce nonalcoholic fatty liver risk, which can interact with choline metabolism.
  • Discuss pregnancy planning with your provider; pregnancy increases choline requirements and adequate supply supports fetal brain development.

Recommended Blood Tests and Monitoring

  • Serum choline or plasma choline if available in your lab panel.
  • Plasma homocysteine to assess methylation status; elevated levels may indicate need for increased methyl donors.
  • Folate and vitamin B12 to ensure cofactor sufficiency for methionine cycle reactions.
  • Liver function tests and lipid panel if you have risk factors for fatty liver disease or abnormal liver enzyme history.

When to Consult a Healthcare Provider

Always discuss genetic findings and any plan to change diet or start supplements with your healthcare provider. Seek professional guidance if you have elevated homocysteine, abnormal liver tests, pregnancy, chronic alcohol use, or symptoms like persistent fatigue, unexplained muscle weakness, or cognitive changes. Your provider can help integrate genotype information with clinical context and any necessary medical treatment.

Limitations and Disclaimer

This information is educational and based on genetic predisposition related to CHDH and rs12676. PlexusDx does not provide medical advice. Genetic results describe potential risks and tendencies, not diagnoses. Consult your healthcare provider before making medical decisions, beginning supplements, or changing your treatment or diet.

If this genetic variant is present in your PlexusDx results, the following tests and reports are commonly used to explore it further:

🧬 Genetic Tests:

🧪 Blood Tests:

📄 Genetic Report:

Frequently Asked Questions About Methionine Cycle and CHDH rs12676

What does the CHDH rs12676 variant mean for methylation and liver health?

The CHDH gene helps convert choline into betaine (TMG), which supports the methylation cycle by helping convert homocysteine into methionine. With the rs12676 effect allele, enzyme efficiency may be reduced, which can increase reliance on dietary choline and methyl-supporting cofactors—potentially affecting methylation balance, phosphatidylcholine production (important for cell membranes), and over time contributing to higher homocysteine or liver fat metabolism changes, especially under stressors like low choline intake or alcohol use.

How do rs12676 genotypes (AA, AC, CC) differ in potential health risk?

AA (two effect alleles) may indicate the greatest reduction in CHDH activity, increasing the chance of methylation imbalance, elevated homocysteine, and lower phosphatidylcholine production when dietary choline is low or with high alcohol use. AC (one effect allele) may reflect a partial reduction, where CHDH function can still be suboptimal under certain conditions (e.g., low choline intake, pregnancy, or heavy alcohol consumption). CC (zero effect alleles) is typically associated with normal CHDH activity, meaning the baseline risk from this gene alone is lower.

What diet, supplement, and lab monitoring steps are commonly recommended for rs12676?

Common recommendations include prioritizing choline-rich foods (e.g., eggs, liver, poultry, fish, shellfish, and dairy), adding betaine-containing foods (e.g., beets, spinach, quinoa, wheat bran, shellfish), supporting methylation with folate and vitamin B12, and maintaining omega-3 intake for membrane and liver support. Limiting excessive alcohol is also important because alcohol increases choline demand. Supplements sometimes considered (with clinician guidance) include choline (e.g., choline bitartrate or alpha-GPC), betaine/TMG, and methyl-donor B vitamins (e.g., 5-MTHF, methylcobalamin, and B6). Typical monitoring may include plasma homocysteine, folate, vitamin B12, choline (if available), and liver function tests with a lipid panel if fatty liver risk factors or abnormal liver history exist. Discuss results and any supplement plan with your healthcare provider.

What tests can help me learn more about Methionine Cycle and CHDH rs12676?

The Genetic Methylation Test delivers over 300 genetic insights related to methylation, detoxification, and nutrient processing. The Methylation Pathway Genetic Report translates your results into personalized, actionable guidance. Your healthcare provider can also recommend targeted blood tests based on your specific pathway results and health history to complement your genetic insights with current biomarker data.

Medical and Editorial Standards

Medical review process: This article was reviewed for medical accuracy, scientific clarity, evidence alignment, and appropriate discussion of genetics, medications, supplements, biomarkers, and health-related claims.

Sources and evidence: PlexusDx educational content is developed using peer-reviewed research, clinical literature, reputable medical references, and, where applicable, public health or regulatory guidance. References are included at the end of the article when scientific, medical, or health-related claims are discussed.

Commercial transparency: PlexusDx offers genetic testing, blood biomarker testing, personalized supplement recommendations, and related precision wellness services. Product mentions are intended to help readers understand available options and should not be interpreted as medical advice.

Important disclaimer: PlexusDx educational content is for informational purposes only and should not be used as a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making decisions about medications, supplements, genetic testing, lab testing, or health-related care.