Association of Thyroid Peroxidase Gene Polymorphisms and Serum Anti- TPO Levels in Egyptian Patients with Autoimmune Hypothyroidism.

Background: Thyroid peroxidase (TPO) gene mutation leads to a change in enzyme built structure resulting in the anti-TPO autoantibodies production that may cause thyroid destruction.

Aim: To evaluate the association of three single nucleotide polymorphisms (SNPs) of the TPO gene and anti-TPO levels in Egyptian patients with autoimmune hypothyroidism and correlate them with the disease severity.

Methods: Two hundred patients with newly discovered autoimmune hypothyroidism were included in the study (100 with subclinical hypothyroidism and 100 of them with overt hypothyroidism) and 100 healthy individuals as a control group were genotyped by PCR-REFLP.

Results: The TT genotype of rs2071400 C/T and the T allele were significantly more frequent in patients with subclinical hypothyroidism and overt hypothyroidism than in the control group. But there were no significant differences in the TT genotype and T allele between subclinical and overt hypothyroidism patients. As regards TPO rs732609 A/C polymorphism, the CC genotype of rs732609 A/C and the C allele were significantly increased in patients with subclinical hypothyroidism and overt hypothyroidism than in controls. There was a significant difference in the CC genotype and C allele between subclinical and overt hypothyroidism patients. Concerning TPO rs1126797 C/T polymorphism, there were no significant differences of genotype or allele frequencies between patients groups and control group.

Conclusion: We found an association of rs2071400 C/T and rs732609A/C polymorphisms with autoimmune hypothyroidism and correlated anti-TPO levels with different genotypes in hypothyroid patients. Also, we found an association of rs732609A/C polymorphism with the disease severity.