Question 1

What is the Meaning of DIO2 Polymorphism?

Accepted Answer

DIO2 Polymorphism denotes a genetic variation, typically a single nucleotide polymorphism (SNP), within the deiodinase type 2 gene. This gene encodes the DIO2 enzyme, converting inactive thyroxine (T4) into active triiodothyronine (T3) within cells. These changes impact enzyme efficiency.

Question 2

What is the Context of DIO2 Polymorphism?

Accepted Answer

The DIO2 enzyme is present in tissues like the brain, pituitary, and skeletal muscle. Its function provides intracellular T3, crucial for cellular metabolism, independent of circulating T3. A polymorphism affects the body's ability to activate thyroid hormone locally.

Question 3

What is the Significance of DIO2 Polymorphism?

Accepted Answer

Clinically, specific DIO2 Polymorphism variants, like rs225014 (Thr92Ala), correlate with varied responses to levothyroxine monotherapy. Patients may report persistent hypothyroid symptoms despite normal TSH and T4, suggesting impaired T4 to T3 conversion. This aids personalized management.

Question 4

What is the Mechanism of DIO2 Polymorphism?

Accepted Answer

The DIO2 Polymorphism alters the deiodinase type 2 enzyme's amino acid sequence. The Thr92Ala variant, for instance, replaces threonine with alanine, potentially reducing catalytic activity. This leads to less efficient T4 to T3 conversion, lowering intracellular T3 and impacting metabolic processes.

Question 5

What is the Application of DIO2 Polymorphism?

Accepted Answer

Genetic testing for DIO2 Polymorphism may be considered for patients with ongoing hypothyroid symptoms, like fatigue, despite optimized levothyroxine monotherapy and normal TSH/free T4. Identifying variants offers a biological explanation and can inform discussions about alternative strategies, including T4/T3 combination.

Question 6

What is the Metric of DIO2 Polymorphism?

Accepted Answer

DIO2 Polymorphism is identified via genetic analysis, typically DNA sequencing from blood or saliva, to detect specific single nucleotide variations. While this genetic data offers insight into predisposition, clinical thyroid status relies on measuring serum TSH, free T4, and free T3, alongside symptom evaluation.

Question 7

What is the Risk of DIO2 Polymorphism?

Accepted Answer

A key risk regarding DIO2 Polymorphism is misinterpretation or overemphasis on genetic data without proper clinical correlation. Solely basing treatment decisions on genetic variants, without integrating lab findings and patient symptoms, could lead to inappropriate interventions, causing adverse effects or ongoing discomfort.

DIO2 Polymorphism

Meaning

Context

Significance

Mechanism

Application

Metric

Risk

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