Activating TSH-receptor mutation (Met453Thr) as a cause of adenomatous non-autoimmune hyperthyroidism in a 3-year-old boy.
Several mutations of the TSH-receptor gene have been described in a variety of thyroid diseases. Particularly in children and adolescents, somatic or germ cell mutations may lead to hyperthyroidism. In these cases, molecular analysis of the TSHR gene provides important information for further clinical management. We report a 3-year-old boy with a rare somatic TSHR mutation causing autonomous adenoma of the thyroid gland in order to illustrate how the genetic analysis of the lesion impacted on the surgical strategy. The patient presented with a left neck mass, negative thyroid autoantibodies, and unifocal autonomy on thyroid scan. He underwent local resection of the adenoma. Genetic workup demonstrated a somatic mutation of TSHR. Exons 9 and 10 of the TSHR gene (chromosome 14q3) from peripheral blood DNA and toxic thyroid adenoma tissue DNA were amplified by PCR and analyzed by denatured gradient gel electrophoresis (DGGE). DGGE from the EDTA blood sample showed no difference compared to the wild-type, whereas material extracted from the tissue sample showed a mutation in exon 10. Direct sequencing of the PCR product from the tissue demonstrated a heterozygous mutation in codon 453 (ATG-->ACG), leading to a substitution of methionine by threonine. The genetic appraisal of resected thyroid tissue in cases with nonautoimmune hyperthyroidism is important to formulate surgical and medical treatment plans. In cases with somatic mutations of the TSHR, simple resection of the adenoma is sufficient, whereas total thyroidectomy should be considered in patients with germ cell mutations.
Kraemer
Sebastian
S
Department of Paediatric Surgery, University Hospital of Leipzig, Leipzig, Germany. sebastian-kraemer@web.de
Rothe
Karin
K
Pfaeffle
Roland
R
Fuehrer-Sakel
Dagmar
D
Till
Holger
H
Muensterer
Oliver J
OJ
D000236:Adenoma / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D000328:Adult; D002675:Child, Preschool; D004252:DNA Mutational Analysis; D005260:Female; D006801:Humans; D006980:Hyperthyroidism / Q000235:genetics* / Q000378:metabolism; D008297:Male; D009154:Mutation; D010375:Pedigree; D011989:Receptors, Thyrotropin / Q000235:genetics*; D013961:Thyroid Gland / Q000000981:diagnostic imaging / Q000601:surgery; D013964:Thyroid Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D013965:Thyroidectomy; D016896:Treatment Outcome; D014463:Ultrasonography
D011989:Receptors, Thyrotropin