Hypothyroid is a condition that causes low thyroid function. The thyroid is a gland in the neck that makes thyroid hormone. Thyroid hormone helps regulate the body’s energy, metabolism and other functions.

Doctors can diagnose hypothyroid through a blood test. The blood test checks the following:

  • Thyroid stimulating hormone (TSH) is a hormone from the brain that tells the thyroid to turn on. If TSH levels are high, it may mean the thyroid is not working properly.
  • Thyroxine or free thyroxine (T4 or free T4) level is the actual level of thyroid hormone is flowing throughout the body. This tells how much hormone the body is making.
  • Subclinical hypothyroidism. This condition is common in children with WS. It is a condition in which the TSH levels are a little high but the T4 level is normal.


  • Fatigue
  • Feeling cold more easily
  • Constipation
  • Dry, coarse (rough) hair and skin
  • Hair loss


In most cases, hypothyroid issues are mild in people with WS. They might not need medication to replace the body’s missing thyroid hormone. If your child does need thyroid medication, it comes in a pill. Children with WS also need blood tests every 1-2 years to check their thyroid.

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Rev. 8/2019. Mass General for Children and Massachusetts General Hospital do not endorse any of the brands listed on this handout. This handout is intended to provide health information so that you can be better informed. It is not a substitute for medical advice and should not be used to treatment of any medical conditions.