The role of PAX-8, TTF-1 AND TTF-2 gene polymorphisms in children with congenital hypothyroidism due to thyroid dysgenesis

Objective: We aimed to investigate whether there is any relation between congenital hypothyroidism due to thyroid dysgenesis and PAX-8, TTF-1, TTF-2 gene polymorphisms in children. Investigations of functions of polymorphisms in these genes can provide valuable information for further studies about diagnosis, treatment, pathogenesis of congenital hypothyroidism, and may give new ideas about preventing this disease.Patients and Methods: 200 children were included to this study. A hundred of 200 children were suffering from congenital hypothyroidism and the remainder was healthy. Age of diagnosis, gender, TSH level, free T4 level, thyroglobulin level and ultrasonographic findings of all patients were recorded. Firstly DNA extraction was done from blood samples of all children. TTF1 (rs3739914), TTF1 (2054238), TTF2 (rs998532), and PAX8 (rs80049915) gene regions were proliferated by PCR method. Sequences which have single nucleotide polymorphism (SNP) have determined for each gene region after lining up procedure for DNA.Results: No polymorphism was found on TTF1 (rs3739914) gene region in neither congenital hypothyroidism group nor healthy group. Polymorphism was found on gene region of TTF1 (2054238 C/T) in 76 children with congenital hypothyroidism and also CT heterozygote mutation was in 24 patients of the same group. No polymorphism was found in 80 children of healthy group but CT heterozygote mutation was detected in 20 ones of the same group. It was found that gene polymorphism of TTF1 (2054238 C/T) is not a risk factor for this disease (odds=0,766[0,387-1,518], p=0,445). No polymorphism was detected on TTF-2 (rs998532) gene region in 94 children of congenital hypothyroidism group; GA heterozygote mutation in 4 children and GG homozygote mutation in 2 children was detected in the same group. No polymorphism were detected in 96 children of healthy group, GA heterozygote mutation was detected in 4 children of the same group. It was found that TTF2 (rs998532) gene polymorphisms are not a risk factors for this disease (odds=0,707[0,189-2,641], p=0,606). No polymorphism is detected in on PAX8 (rs80049915) gene region in neither congenital hypothyroidism group nor healthy group.Conclusion: No polymorphism on the mostly seen regions of PAX-8, TTF-1, and TTF-2 genes which shows SNP was found in children with congenital hypothyroidism due to thyroid dysgenesis.Keywords: Child, Dysgenesis, Genotype, Congenital hypothyroidism