Our molecular testing of the p.A119S variation in both rat heart derived (H10) cells and HELA cells showed no difference in transactivation of any of the four promoters tested (NPPA, Tg, Dio2, TPO), which is in contrast to the results obtained by Dentice et al. Nevertheless, the results of our functional studies are in agreement with our clinical data as the mutation did not segregate with CHD in our familial case and none of our seven mutation carriers had thyroid disease. Here, TPO is linked to thyroiditis.