Thyroid dysgenesis

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs.

Thyroid hypoplasia is a form of thyroid dysgenesis (see this term) characterized by incomplete development of the thyroid gland that results in primary congenital hypothyroidism (see this term), a permanent thyroid deficiency that is present from birth.

Prevalence is estimated at around 1/28,000. Thyroid hypoplasia and athyreosis (see this term) combined account for one-third of cases of thyroid dysgenesis.

Clinical manifestations of thyroid hypoplasia are often subtle or not present at birth, probably as a result of trans-placental passage of some maternal thyroid hormone or due to the fact that many infants have some thyroid production of their own. More specific symptoms and signs do not develop until several months of age. Common clinical features and signs include decreased activity and increased sleep, feeding difficulty and constipation, prolonged jaundice, myxedematous facies, large fontanels (especially posterior), macroglossia, a distended abdomen with umbilical hernia, and hypotonia. Goiter is always absent. Slow linear growth and developmental delay are usually apparent by 4-6 months of age. Without treatment thyroid hypoplasia results in severe intellectual deficit and short stature.

Familial cases of thyroid hypoplasia are caused by mutations in the FOXE1, NKX2-1, NKX2-5 or PAX8 genes (9q22, 14q13, 5q34 and 2q12-q14). Mutations that result in partial inactivation of the TSHR gene (14q31) can present with thyroid hypoplasia.

Imaging studies are required to confirm the diagnosis.

Thyroid hypoplasia is generally thought to be sporadic. However, recent evidence points to the possibility of a genetic component. Around 2% of cases have been shown to be familial.

Visit the Orphanet disease page for more resources.

Last updated: 8/1/2010

Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.

If you need medical advice, you can look for doctors or other healthcare professionals who have experience with this disease. You may find these specialists through advocacy organizations, clinical trials, or articles published in medical journals. You may also want to contact a university or tertiary medical center in your area, because these centers tend to see more complex cases and have the latest technology and treatments.

If you can’t find a specialist in your local area, try contacting national or international specialists. They may be able to refer you to someone they know through conferences or research efforts. Some specialists may be willing to consult with you or your local doctors over the phone or by email if you can't travel to them for care.

You can find more tips in our guide, How to Find a Disease Specialist. We also encourage you to explore the rest of this page to find resources that can help you find specialists.

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.