Routine biochemical parameters and type II deiodinase Thr92Ala polymorphism with early thyroid dysfunction in asymptomatic young women: A cross-sectional study

Background: Early thyroid dysfunction frequently remains undetected in young women, emphasizing the importance of identifying sensitive biochemical and genetic markers for early detection. Objective: This study investigates whether routine biochemical markers and the type II deiodinase (DIO2) Thr92Ala gene polymorphism (rs225014) correlate with early thyroid imbalances in asymptomatic young women. Materials and Methods: A cross-sectional observational study was conducted on 38 asymptomatic women aged 17–26 years. Tests included complete blood count, lipid profile, iron and vitamin levels (Vitamin B12 and Vitamin D), kidney and liver function, thyroid function tests (TFTs), and genotyping for the DIO2 SNP (rs225014). Data were analyzed using multiple linear regression and ANOVA. Results: Altered TFTs were observed in 13% of participants. Lower iron and low-density lipids levels were observed in 39% of females, while Vitamin B12 was elevated in 34%. Vitamin D deficiency was universal (100%), with low high-density lipoprotein and ferritin in 34% and 24%, respectively. Changes in cholesterol, thyroid, and blood parameters were noted. However, regression analyses found no significant correlation between thyroid markers and routine biochemical parameters, suggesting largely unaltered metabolism in these healthy women. Genotype distribution was 55% AA (wild-type), 32% AG (heterozygous), and 13% GG (mutant). Some individuals with AG and GG genotypes showed changes in thyroid-stimulating hormone, anti-thyroid peroxidase, and serum iron, indicating potential subclinical thyroid deviations. Conclusion: Routine biochemical markers alone may not predict thyroid dysregulation in healthy young females. However, DIO2 gene variations (AG and GG genotypes) may influence thyroid hormone metabolism and predispose individuals to latent endocrine changes, supporting genetic screening for earlier detection and preventive care.