Common variants in the G protein beta3 subunit gene and thyroid disorders in a formerly iodine-deficient population.
BACKGROUND
Heterotrimeric G proteins are key mediators of signals from membrane receptors-including the thyroid-stimulating hormone (TSH) receptor-to cellular effectors. Gain-of-function mutations in the TSH receptor and the Galpha(S) subunit occur frequently in hyperfunctioning thyroid nodules and differentiated thyroid carcinomas, whereby the T allele of a common polymorphism (825C>T, rs5443) in the G protein beta3 subunit gene (GNB3) is associated with increased G protein-mediated signal transduction and a complex phenotype. The aim of this study was to investigate whether this common polymorphism affects key parameters of thyroid function and morphology and influences the pathogenesis of thyroid diseases in the general population.


METHODS
The population-based cross-sectional Study of Health in Pomerania is a general health survey with focus on thyroid diseases in northeast Germany, a formerly iodine-deficient area. Data from 3428 subjects (1800 men and 1628 women) were analyzed for an association of the GNB3 genotype with TSH, free triiodothyronine and thyroxine levels, urine iodine and thiocyanate excretion, and thyroid ultrasound morphology including thyroid volume, presence of goiter, and thyroid nodules.


RESULTS
There was no association between GNB3 genotype status and the functional or morphological thyroid parameters investigated, neither in crude analyses nor upon multivariable analyses including known confounders of thyroid disorders.


CONCLUSIONS
Based on the data from this large population-based survey, we conclude that the GNB3 825C>T polymorphism does not affect key parameters of thyroid function and morphology in the general population of a formerly iodine-deficient area.
Völzke
Henry
H
Study of Health in Pomerania (SHIP)/Clinical-Epidemiological Research, Institute of Community Medicine, Ernst-Moritz-Arndt University, Greifswald D-17487, Germany. voelzke@uni-greifswald.de
Bornhorst
Alexa
A
Rimmbach
Christian
C
Petersenn
Holger
H
Geissler
Ingrid
I
Nauck
Matthias
M
Wallaschofski
Henri
H
Kroemer
Heyo K
HK
Rosskopf
Dieter
D
D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D005260:Female; D014644:Genetic Variation; D005838:Genotype; D005858:Germany / Q000453:epidemiology; D020962:Heterotrimeric GTP-Binding Proteins / Q000235:genetics*; D006801:Humans; D007455:Iodine / Q000172:deficiency*; D008019:Life Style; D008297:Male; D008875:Middle Aged; D011153:Population; D012959:Socioeconomic Factors; D013959:Thyroid Diseases / Q000000981:diagnostic imaging / Q000235:genetics*; D013960:Thyroid Function Tests; D013963:Thyroid Hormones / Q000097:blood; D014463:Ultrasonography; D055815:Young Adult
C454420:G-protein beta3 subunit; D013963:Thyroid Hormones; D007455:Iodine; D020962:Heterotrimeric GTP-Binding Proteins