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Living with Thyroid hemiagenesis

A condition present at birth in which half of the thyroid gland is missing, often with no symptoms.

Understanding Thyroid hemiagenesis

Thyroid hemiagenesis is a form of thyroid development difference in which half of the thyroid gland is missing from birth.

It usually causes no symptoms. In some people it leads to lasting low thyroid hormone from birth (congenital hypothyroidism). It is noticed in the newborn period.

Signs & symptoms

Symptoms vary from person to person. GARD lists these among the most common:

  • Often no symptoms
  • Tiredness (fatigue)
  • Constipation
  • Growth delay and global developmental delay
  • Low muscle tone (hypotonia)
  • Thyroid nodules or other thyroid conditions

Not everyone has every symptom. GARD's list comes from the Human Phenotype Ontology.

Diagnosis

  1. Talk with your doctor

    Share the symptoms you've noticed, when they started and your family health history. Notes and photos can help.

  2. See a specialist

    Specialists who may be involved include genetic specialists and hormone specialists.

  3. Ask which tests can help

    Your care team will decide which exams and tests can confirm the diagnosis.

Care & treatment

Care team
Genetic specialists (geneticists); Hormone specialists (endocrinologists)
Expert care
Ask about multidisciplinary care centers for rare conditions
Treatment
GARD doesn't list specific treatments for this condition. Your care team will tailor care to your symptoms.
Research
Clinical trials and observational studies may be options. See the research section below.

General information, not medical advice. Your care team makes the decisions.

Everyday life

Living with a rare condition is easier with support.

  • Connect with rare disease patient organizations for support
  • Keep notes on symptoms, changes and questions for appointments
  • Ask about patient registries that help research
  • Look into financial aid and travel resources for care visits
Bring these questions to your next doctor visit
How are my or my child's thyroid hormone levels checked?
Which specialists, such as an endocrinologist, should we see?
What follow-up does the remaining thyroid need?

Quick facts

Symptoms usually startNewborn

GARD says changes in genes (variants) cause this condition, but it doesn't name a specific gene.

GeneticEndocrine

Also known as: congenital absence of half of thyroid; congenital hemiagenesis of thyroid

Patient organizations

Rare-disease groups that can help

Source: NIH GARD · Thyroid hemiagenesisGARD ID 16844 · GARD page updated September 2026 · Plain-language summary by Know Rare; editorial review pending. General information, not medical advice.

You are more than your diagnosis

Perspectives from people navigating life with Thyroid hemiagenesis.

Explore the Thyroid hemiagenesis blog

Explore research for Thyroid hemiagenesis

Explore actively recruiting Thyroid hemiagenesis studies with HealthSpark.

HealthSpark

Find actively recruiting studies for Thyroid hemiagenesis with HealthSpark. Share your city to explore research near you.

  • Recruiting studies from ClinicalTrials.gov
  • Share your city to look for research near you
  • Eligibility is confirmed by the study team

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Powered by HealthSpark, our AI chat helper · Study information from ClinicalTrials.gov · Eligibility is confirmed by the study team.

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