Frequency of UCP2 45-bp Ins/Del Polymorphism in Saudi Population from Jazan Area and Its Association with Autoimmune Hypothyroidism 45-bp Ins/Del Frequency in Hypothyroidism

Objectives: Autoimmune hypothyroidism (AHT) is a common endocrine disorder. Although the exact cause of AHT is not yet understood, genetic factors may play a major role. Uncoupling protein 2 (UCP2) is a member of mitochondrial protein family involved in the regulation of cellular metabolism. An important functional polymorphism in the gene, 45-bp insertion/deletion (ins/del) polymorphism, has been linked to certain clinical conditions. However, an association between the 45-bp ins/del polymorphism and AHT has not yet been established.

Methods: In this study, about 259 blood samples were collected from, patients with AHT and age-matched healthy control subjects. DNA was extracted for 45-bp ins/del polymorphisms genotyping, using a standard polymerase chain reaction technique. The distribution of different genotypes was determined in both groups and possible association with AHT was also assessed by logistic regression analysis using the Del/Del variant as a reference genotype.

Results: The frequency of the 45-bp ins/del polymorphism in the total study population was 49.04%, 40.15%, and 10.81% for Del/Del, Ins/Del, and Ins/Ins genotypes, respectively. The logistic regression analysis showed crude odds ratios (ORs), respectively, with their 95% confidence intervals (CIs) and -values in codominant (Del/Ins) (OR = 1.53, CI = 0.89-2.60, = 0.17), codominant (Ins/Ins) (OR = 0.75, CI = 0.34-1.74, = 0.53), dominant (OR = 1.30, CI = 0.79-2.16, = 0.37), and recessive (OR = 0.62, CI = 0.29-1.36, = 0.30) inheritance models tested, where none of which were statistically significant.

Conclusion: Our data revealed the distribution of the 45-bp ins/del polymorphisms in Jazan area and confirmed the lack of association between these genetic variants and the development of AHT.