Subclinical hyperthyroidism due to a thyrotropin receptor (TSHR) gene mutation (S505R).
OBJECTIVE
To identify the molecular defect by which non-autoimmune subclinical hyperthyroidism was caused in a 6-mo-old infant who presented with weight loss.


METHODS
Congenital non-autoimmune hyperthyroidism is caused by activating germline mutations in the thyrotropin receptor (TSHR) gene. Therefore, the TSHR gene was sequenced directly from the patient's genomic DNA.


RESULTS
Molecular analysis revealed a heterozygous point mutation (S505R) in the TSHR gene as the underlying defect.


CONCLUSIONS
A constitutively activating mutation in the TSHR gene has to be considered not only in patients with severe congenital non-autoimmune hyperthyroidism, but also in children with subclinical non-autoimmune hyperthyroidism.
Pohlenz
Joachim
J
Children's Hospital of the Johannes Gutenberg University, Mainz, Germany. pohlenz@kinder.klinik.uni-mainz.de
Pfarr
Nicole
N
Krüger
Silvia
S
Hesse
Volker
V
D000328:Adult; D005260:Female; D006801:Humans; D006980:Hyperthyroidism / Q000097:blood / Q000145:classification / Q000235:genetics*; D007223:Infant; D008297:Male; D010375:Pedigree; D017354:Point Mutation / Q000235:genetics*; D011989:Receptors, Thyrotropin / Q000235:genetics*
D011989:Receptors, Thyrotropin