title: Functional studies of new TSH receptor (TSHr) mutations identified in patients affected by hypothyroidism or isolated hyperthyrotrophinaemia.
abstract: OBJECTIVE
  To establish the role of new TSH receptor (TSHr) variants (P27T, E34 K, R46P, D403N, W488R and M527T) recently identified in children with congenital hypothyroidism (CH) or subclinical hypothyroidism (SH) with a thyroid gland of normal size.
  
  
  METHODS
  TSHr variants were obtained by mutagenesis. Wild-type (wt) and TSHr mutants were expressed in COS cells and cAMP assay, (125)I-TSH binding and microchip flow cytometry analyses were performed.
  
  
  RESULTS
  D403N and M527T mutants showed a lower cAMP response to bovine TSH (bTSH) with respect to the wtTSHr. R46P and W488R mutants did not show any response to bTSH stimulation in terms of cAMP production. The E34 K mutant showed a significantly lower cAMP response to stimulation with bTSH, while P27T had a lower cAMP response only to the highest dose of bTSH used. P27T, E34 K, D403N and M527T mutants showed a lower TSH binding capacity with respect to the wtTSHr. R46P and W488R mutants did not show any TSH binding.
  
  
  CONCLUSIONS
  E34 K, D403N, M527T, R46P and W488R TSHr variants seem to cause a functional abnormality of the receptor which is responsible for the observed phenotype. The P27T TSHr variant does not seem to play a functional role in the pathogenesis of CH and should be considered as a polymorphism.
authors: Dipartimento di Endocrinologia e Metabolismo, Centro Eccellenza AmbiSEN, Università di Pisa, Pisa, Italy.
authors: Giuseppina
authors: G
authors: De Marco
authors: Patrizia
authors: P
authors: Agretti
authors: Marta
authors: M
authors: Camilot
authors: Francesca
authors: F
authors: Teofoli
authors: Luciano
authors: L
authors: Tatò
authors: Paolo
authors: P
authors: Vitti
authors: Aldo
authors: A
authors: Pinchera
authors: Massimo
authors: M
authors: Tonacchera
mesh_terms: D000818:Animals; D019556:COS Cells; D002648:Child; D002675:Child, Preschool; D002522:Chlorocebus aethiops; D003409:Congenital Hypothyroidism / Q000235:genetics*; D005260:Female; D006801:Humans; D007037:Hypothyroidism / Q000097:blood* / Q000235:genetics*; D007231:Infant, Newborn; D008297:Male; D009154:Mutation / Q000235:genetics*; D010641:Phenotype; D011989:Receptors, Thyrotropin / Q000235:genetics*; D013972:Thyrotropin / Q000097:blood*
chemical_list: D011989:Receptors, Thyrotropin; D013972:Thyrotropin