Thyroid | TSHR (rs121908866)

If your genotype is AA at rs121908866, you carry two copies of the effect allele. This configuration has been associated with congenital hypothyroidism. That means the thyroid may have a reduced ability to respond to TSH, which can result in lower production of thyroid hormones from birth forward.

Possible signs and reproductive impacts

• Persistent fatigue, intolerance to cold, or unexplained weight gain
• Irregular menstrual cycles or heavier periods
• Difficulty conceiving or reduced fertility related to disrupted ovulation and hormone balance

What to monitor

• TSH, free T4, and free T3 levels on a regular basis or when symptoms change
• Thyroid antibody testing if autoimmune thyroid disease is suspected
• Assessment of iron, selenium, vitamin D, and other nutrients that support thyroid function

Diet and nutrition

• Ensure adequate iodine intake through iodized salt or marine sources unless advised otherwise by your provider
• Include selenium rich foods such as Brazil nuts (small amounts), seafood, and lean meats
• Optimize iron from lean meats, legumes, or fortified foods; correct deficiencies which can impair thyroid hormone production
• Consume foods with vitamin A and zinc such as liver alternatives, eggs, dairy or fortified options, and pumpkin seeds
• Limit excessive intake of raw soy and large amounts of cruciferous vegetables if iodine intake is low; cooking reduces goitrogenic compounds
• Consider a gluten trial if you have symptoms or risk factors for autoimmune thyroid disease

Supplements and medical follow up

• Only take thyroid hormone replacement if prescribed by your healthcare provider based on lab testing
• Supplemental iodine, selenium, iron, or zinc may be helpful when deficiency is confirmed by testing and guided by your provider
• A multivitamin that supplies supportive nutrients can be considered if dietary intake is inadequate

Lifestyle and environmental considerations

• Prioritize sleep and stress reduction; chronic stress alters hormone balance and can worsen symptoms
• Avoid known endocrine disruptors in some plastics, personal care products, and certain pesticides
• Maintain a healthy weight and regular physical activity to support metabolism and reproductive health

If your genotype is AG, you carry one copy of the effect allele. This variant is associated with an increased risk of congenital hypothyroidism, meaning the thyroid may be somewhat less responsive to TSH and there is a higher chance of lower thyroid hormone levels compared to the most common genotype.

Possible signs and reproductive impacts

• Subtle fatigue, mild weight changes, or cold intolerance
• Changes in menstrual regularity or difficulties with ovulation in some people
• Potential contribution to fertility challenges when combined with other risk factors

What to monitor

• Annual or symptom-triggered testing of TSH and free T4
• Consider checking iron, selenium, and vitamin D if symptoms are present

Diet and nutrition

• Support thyroid function with adequate iodine from iodized salt or dietary sources
• Eat selenium rich foods such as nuts, seafood, and lean proteins
• Include iron rich foods and consider pairing with vitamin C to improve absorption
• Keep soy and raw cruciferous vegetables in moderation if overall iodine intake is low

Supplements and medical follow up

• Discuss targeted supplementation with your provider based on lab results
• Routine monitoring allows early detection of developing hypothyroidism so treatment can be started when appropriate

Lifestyle and environment

• Manage stress through relaxation techniques, mindful movement, or counseling as needed
• Prioritize consistent sleep and regular exercise to support metabolism and hormonal balance
• Reduce exposure to endocrine disruptors in household and personal care products

If your genotype is GG, you carry two copies of the non-effect allele. This is the most common result and is associated with typical TSH receptor function. Your thyroid is expected to respond normally to TSH and to regulate thyroid hormone production effectively.

Even with a common genotype you can still develop thyroid issues from other causes, so general thyroid care is recommended.

General recommendations

• Maintain a balanced diet with adequate iodine, selenium, iron, vitamin A, and zinc
• Test thyroid function if you notice symptoms such as fatigue, weight change, or menstrual irregularities
• Follow healthy lifestyle habits: sleep, stress management, exercise, and limiting exposure to endocrine disruptors