Related Experiment Videos
The extracellular thyrotropin receptor domain is not a major candidate for mutations in toxic thyroid nodules
D Führer1, C Kubisch, U Scheibler
1Department of Internal Medicine III, University of Leipzig, Germany.
Abstract:
Constitutive activation of the cyclic adenosine monophosphate (cAMP) cascade by either thyrotropin receptor (TSHR) or gsp mutations is considered to be the major molecular cause of toxic thyroid nodules (TTNs). In a recent study we investigated a consecutive series of 31 TTNs and identified 15 somatic TSHR mutations (n = 14 in exon 10; n = 1 in exon 9) but no mutations in gsp exons 7-10. The purpose of the present study was to determine whether the extracellular TSHR domain would be a candidate for mutations causing TTNs. Therefore, we screened TSHR exons 1-8 in the remaining 16 TTNs without mutations in TSHR exons 9 and 10 and gsp exons 7-10 of our previous study. Except for a known functional polymorphism in exon 1 (Pro 52 Thr) in 2 TTNs and a silent base exchange in exon 7 (187 Asn) in 7 other TTNs no TSHR mutations were identified. To clarify the molecular etiology of TTNs without TSHR or gsp mutations, candidate genes in other steps of the cAMP cascade have to be considered.
Insights
Constitutive activation of the cyclic adenosine monophosphate (cAMP) cascade causes toxic thyroid nodules (TTNs). Researchers found no new TSHR mutations in the extracellular domain, suggesting other genes may be involved.
Area of Science:
- Endocrinology
- Molecular Biology
- Genetics
Background:
- Constitutive activation of the cyclic adenosine monophosphate (cAMP) cascade, primarily through thyrotropin receptor (TSHR) or gsp mutations, is a leading cause of toxic thyroid nodules (TTNs).
- Previous research identified somatic TSHR mutations in a subset of TTNs, implicating specific regions of the receptor in disease pathogenesis.
Purpose of the Study:
- To investigate the extracellular domain of the TSHR as a potential site for mutations causing TTNs.
- To identify the molecular etiology of TTNs in cases lacking mutations in TSHR exons 9 and 10, and gsp exons 7-10.
Main Methods:
- Screening of TSHR exons 1-8 in 16 TTNs that did not harbor mutations in TSHR exons 9-10 or gsp exons 7-10.
- Analysis included identification of known polymorphisms and silent base exchanges.
Main Results:
- No novel TSHR mutations were identified in the screened extracellular domain (exons 1-8).
- A known functional polymorphism (Pro52Thr) was found in 2 TTNs, and a silent base exchange (187Asn) in 7 TTNs.
- This indicates that mutations in the extracellular TSHR domain are not a common cause of TTNs in the studied cohort.
Conclusions:
- The extracellular domain of TSHR is unlikely to be a major site for mutations causing TTNs.
- Further investigation into other genes within the cAMP cascade is necessary to elucidate the molecular basis of TTNs lacking TSHR or gsp mutations.