title: Potent thyrotrophin receptor-blocking antibodies: a cause of transient congenital hypothyroidism and delayed thyroid development.
abstract: OBJECTIVE
  We describe an infant with surprisingly severe neonatal hypothyroidism due to transplacental passage of thyrotrophin receptor (TSH-R)-blocking antibodies (TBAb).
  
  
  METHODS
  TBAb were detected using a cell line which stably expresses the human TSH-R and a cAMP-responsive luciferase reporter by their ability to inhibit TSH-stimulated luciferase expression. Potent TBAb were detected in maternal serum and initially in the infant's serum but, in the latter, TBAb decreased over time to within the reference range by 3-4 months of age, illustrating the transient nature of this condition.
  
  
  RESULTS
  The thyroid function of this child did not return to normal on withdrawal of thyroxine therapy at 16 months of age when he developed transient compensated hypothyroidism.
  
  
  CONCLUSIONS
  We propose that the presence of potent TBAb in utero and in the first weeks of life may have implications for the development of a normally sized thyroid gland. We have demonstrated the presence of TBAb in the mother's milk and, as far as we are aware, this is the first such report. However, the TBAb in the milk probably did not contribute significantly to hypothyroidism in the child, given the reducing antibody titre in his circulation.
authors.affiliation: Department of Medical Biochemistry, University Hospital of Wales, Heath Park, Cardiff CF14 4XN, UK. carol.evans@cardiffandvale.wales.nhs.uk
authors.forename: C
authors.initials: C
authors.lastname: Evans
authors.forename: N J
authors.initials: NJ
authors.lastname: Jordan
authors.forename: G
authors.initials: G
authors.lastname: Owens
authors.forename: D
authors.initials: D
authors.lastname: Bradley
authors.forename: M
authors.initials: M
authors.lastname: Ludgate
authors.forename: R
authors.initials: R
authors.lastname: John
mesh_terms: D001323:Autoantibodies / Q000097:blood* / Q000276:immunology; D003409:Congenital Hypothyroidism; D006801:Humans; D007037:Hypothyroidism / Q000097:blood / Q000276:immunology; D018828:Immunoglobulins, Thyroid-Stimulating; D007231:Infant, Newborn; D008297:Male; D011989:Receptors, Thyrotropin / Q000037:antagonists & inhibitors* / Q000097:blood* / Q000276:immunology; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood / Q000627:therapeutic use; D014284:Triiodothyronine / Q000097:blood
chemical_list: D001323:Autoantibodies; D018828:Immunoglobulins, Thyroid-Stimulating; D011989:Receptors, Thyrotropin; C094372:thyrotropin-binding inhibitory immunoglobulin; D014284:Triiodothyronine; D013972:Thyrotropin; D013974:Thyroxine