||no association with increased thyroid hormone metabolism
||may have normal to good thyroid hormone metabolism
||likely good thyroid hormone metabolism
[PMID 12788902] Polymorphisms in thyroid hormone pathway genes are associated with plasma TSH and iodothyronine levels in healthy subjects. This 2003 study found that the DIO1 gene's D1b-A/G polymorphism (rs12095080) allele G correlated with lower rT3/T4 and higher T3/rT3 ratios, suggesting increased D1 (Deiodinase type 1) expression and/or activity of this variant. Researchers explained that liver D1 plays a key role not only in the production of plasma T3 from T4 but also in the breakdown of the metabolite rT3 (reverse T3).
[PMID 18815314] Cellular and molecular basis of deiodinase-regulated thyroid hormone signaling.. This 2008 review identified the SNPs of D1a-C/T (rs11206244), and D1b-A/G (rs12095080) and cited the results of the 2003 study [PMID 12788902] on these polymorphisms.
[PMID 21715540] The Type 2 Deiodinase ORFa-Gly3Asp Polymorphism (rs12885300) Influences the Set Point of the Hypothalamus-Pituitary-Thyroid Axis in Patients Treated for Differentiated Thyroid Carcinoma. This study analyzed DIO1-rs12095080 but found more significant effect with SNP DIO2-rs12885300. However, their data depended on TSH and T4 levels alone, since T3 and rT3 were measured at only one time point during the study.