Prolonged and Severe Gestational Thyrotoxicosis Due to Enhanced hCG Sensitivity of a Mutant Thyrotropin Receptor.

CONTEXT: Gestational thyrotoxicosis, whether associated with hyperemesis gravidarum or not, is thought to be due to excessive human chorionic gonadotropin (hCG) secretion.

CASE DESCRIPTION: We report here the second case of gestational thyrotoxicosis associated with hyperemesis gravidarum due to a mutation of the TSH receptor, providing thyroid hypersensitivity to hCG.

CONCLUSION

Severe and lasting gestational thyrotoxicosis with normal hCG concentration should lead to sequencing of the TSH receptor gene.