[1] Essentially this is decreased end organ responsiveness to thyroid hormones.

[2] A new term "impaired sensitivity to thyroid hormone" has been suggested in March 2014 by Refetoff et al.[3] The syndrome can present with variable symptoms, even between members of the same family harboring the same mutation.

It has also been linked to some cases of attention deficit hyperactivity disorder (ADHD), although the majority of people with that diagnosis have no thyroid problems.

The diagnosis may involve identifying a mutation of the thyroid receptor, which is present in approximately 85% of cases.

[citation needed] Thyroid hormone resistance syndrome is rare, incidence is variously quoted as 1 in 50,000 or 1 in 40,000 live births.