Clinically Symptomatic Resistance to Thyroid Hormone β Syndrome Because of THRB Gene Mosaicism.

We highlight that a pathogenic variant in a mosaic state in the THRB gene may be the cause of an authentic RTHβ syndrome. High-throughput sequencing of multiple tissues eases the detection of pathogenic variant in a mosaic state and allows the correct diagnosis of patients with true RTHβ, thus avoiding patient mismanagement.