rs12095080 — DIO1 DIO1 cardiac mortality variant

3' UTR variant in the type 1 deiodinase gene associated with markedly increased cardiac mortality after myocardial infarction

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DIO1 and the Cardiac Thyroid Axis — When Local T3 Drops After a Heart Attack

The heart is among the most metabolically active organs in the body, and triiodothyronine (T3)11 triiodothyronine (T3)
the active form of thyroid hormone that directly enters cardiomyocyte nuclei and regulates gene transcription is one of its principal regulators. T3 governs cardiac contractility, heart rate, coronary vasodilation, and — critically — the regenerative response to ischemic injury. The DIO1 gene encodes type 1 iodothyronine deiodinase22 type 1 iodothyronine deiodinase
a selenoprotein enzyme expressed in liver, kidney, thyroid, and to a lesser extent cardiac tissue, one of three deiodinase enzymes responsible for converting the inactive prohormone T4 into active T3 in peripheral tissues.

The rs12095080 variant sits in the 3' untranslated region of DIO1, a regulatory segment that influences how efficiently the mRNA is translated into functional enzyme.

The Mechanism

DIO1 is a selenocysteine-containing enzyme33 selenocysteine-containing enzyme
requiring dietary selenium for its active site that catalyzes the outer-ring deiodination of T4 to T3. The rs12095080 G allele falls in the 3' UTR — a region that controls mRNA stability, translational efficiency, and microRNA binding.

The Evidence

The primary evidence for rs12095080 comes from a 2020 longitudinal study by Kazukauskiene et al.44 2020 longitudinal study by Kazukauskiene et al.
published in Scientific Reports following 290 patients with acute myocardial infarction over a multi-year period. The AG genotype at rs12095080 predicted cardiac-related mortality with an odds ratio of 3.97 (95% CI 1.45–10.89; p = 0.005)55 odds ratio of 3.97 (95% CI 1.45–10.89; p = 0.005)
a nearly 4-fold increase in mortality risk. The same group previously found rs12095080 associated with hypertension prevalence66 rs12095080 associated with hypertension prevalence
in the same AMI cohort, suggesting broader cardiovascular vulnerability.

The genetic finding is reinforced by extensive evidence linking low T3 syndrome to cardiac outcomes independent of the variant. A 2017 meta-analysis of 41 studies by Wang et al.77 2017 meta-analysis of 41 studies by Wang et al.
International Journal of Cardiology found that low-T3 syndrome in cardiovascular patients was associated with cardiac mortality HR 2.06 (95% CI 1.58–2.69)88 cardiac mortality HR 2.06 (95% CI 1.58–2.69)
and all-cause mortality HR 2.52. In a large 2018 propensity-matched analysis of 2,459 AMI patients99 2018 propensity-matched analysis of 2,459 AMI patients
J Cardiol, low-T3 syndrome (prevalence 23.3%) was associated with in-hospital cardiovascular death rates of 4.7% vs. 1.7% in euthyroid controls, and adding the T3 status to the TIMI risk score meaningfully improved mortality prediction.

Important caveats: the rs12095080 cardiac mortality association comes from a single study with 290 patients from a Lithuanian AMI cohort. Replication in other populations and larger samples is needed before this variant reaches a higher evidence grade. The G allele is also notably rare in East Asian populations (essentially absent), so these findings may not generalize across all ancestries.

Interactions

DIO1 rs12095080 acts within the broader thyroid hormone metabolism pathway, which includes DIO2 (type 2 deiodinase1010 DIO2 (type 2 deiodinase
expressed in cardiac tissue and the brain, plays a complementary T4→T3 conversion role) and DIO3 (type 3 deiodinase1111 DIO3 (type 3 deiodinase
the inactivating enzyme that converts T3 to reverse T3).

Nutrient Interactions

iodine altered_metabolism
selenium increased_need

Genotype Interpretations

What each possible genotype means for this variant.

AA Normal DIO1 Activity Normal

Standard DIO1 enzyme activity; typical cardiac thyroid hormone metabolism

You carry two copies of the common A allele at rs12095080, meaning your DIO1 gene has normal regulatory activity and typical capacity for converting T4 to T3 in peripheral tissues. Approximately 80% of people of European descent share this genotype.

AG Reduced DIO1 Activity Reduced

One G allele increases cardiac mortality risk after heart attack nearly fourfold

The Kazukauskiene et al. 2020 longitudinal study (290 AMI patients, Scientific Reports) found the AG genotype predicted cardiac mortality.

The association with hypertension found in the same cohort (Brozaitiene et al. 2018) suggests this variant may have broader cardiovascular effects beyond the acute MI context.

Important note: this finding comes from a single Lithuanian cohort of 290 patients. Replication studies are needed. G allele carriers should treat this as a meaningful but not definitive signal that warrants proactive monitoring rather than alarm.

GG Significantly Reduced DIO1 Activity Decreased

Two G alleles — very rare genotype

GG homozygotes — rare at ~1% globally and essentially absent in East Asian populations — were likely too few in the 290-patient cohort for a statistically independent estimate.