A de novo pathogenic variant in TSHR expanding the phenotype of persistent sporadic congenital non-autoimmune hyperthyroidism: a case report and literature review

PSNAH may manifest as a multisystem disorder with thyrotoxicosis-associated valvular heart disease as a sentinel presentation. Prenatal thyrotropin receptor hyperactivity and delayed treatment initiation induce structural valvulopathy and cerebellar tonsillar herniation. Early pharmacologic intervention coupled with valve-sparing surgery can restore valvular integrity. The necessity for further neurosurgical intervention in the subsequent management of cerebellar tonsillar herniation requires further longitudinal follow-up.