From Hashimoto's Thyroiditis to Graves' Disease: Why the Switch?

While some patients diagnosed with Hashimoto’s thyroiditis (HT) undergo a condition metamorphism to Graves’ disease (GD), the cause of the autoimmune syndrome switch is unknown.

A team of Italian researchers recently published the results of a small study examining a potential relationship between Down syndrome (DS) and Turner syndrome (TS) chromosomal abnormalities and the transition from HT to GD, which could identify the factors that induce thyroid dysfunction.

Using medical records or questionnaires addressed to family pediatricians, the study authors retrospectively reviewed 35 pediatric GD patients with either DS or TS (group A) and 109 age-matched GD patients with neither DS nor TS (group B). Both groups had similar thyroid function, iodine status, and autoimmunity tests at HT diagnosis.

In addition to searching for antecedent HT, the researchers tried to determine how many patients in each group had subclinical or overt hypothyroidism at the time of HT diagnosis, as well as the number of those who had received L-T4 therapy prior to GD onset.

Though the prevalence of patients who underwent L-T4 therapy prior to GD diagnosis was not significantly different between the 2 groups, the authors found group A patients were significantly more likely to convert from HT to GD than those in group B. Additionally, patients in group A were significantly more likely to have antecedent HT than those in group B.

The authors wrote that their findings suggest chromosomal abnormalities might favor metamorphosis from HT to GD.