[Polymorphism of the 52 triplet gene (nucleotide 253) of the TSH receptor in Basedow-Graves patients and in healthy controls].
It has been analysed the polymorphism of the first exon of TSH receptor gene, at the first nucleotide of the triplet 52 of the genomic DNA (CCC/ACC, Pro/Thr) in Graves' disease and control population and was not found connection between the genetic background, clinical picture and some immunological parameters. Genomic DNA was obtained from formalin-fixed, paraffin embedded thyroid tissue of patients with Graves' disease underwent subtotal thyroidectomy and from peripheral blood leukocytes. The first exon and small part of the first intron of the TSH-R gene was amplified by PCR. The motif was amplified by the primers and primers includes restriction site of the Tth 111 I restriction enzyme and mutant form of the examined nucleotide. Genomic DNA having only wild allele was detected at 189 bp, while mutant allele was digested a 167 and a 22 bp fragments. Three persons (two female and one male) of the 32 patients with Graves' disease had mutation A253 in heterozygotic form: The patient with mutation A253 had no any symptoms of Graves' ophthalmopathy. No correlation was found between mutation A253 and the levels of anti-TSH-R-, anti TG, anti-TPO and anti-eye muscle antibodies. Surprisingly, it was found mutation of heterozygous genotype in two control individuals (one female and one male) of 14 without any symptoms of thyroid disease and negative laboratory findings. Finally, it has not been found the association of the 253 nucleotide of the codon 52 polymorphism with Graves' disease and ophthalmopathy and the allele A253 has no pathogenetic relevance in Graves' disease. On the other hand, it cannot be excluded that other mutation or sequence polymorphism in the remainder of TSH-R extracellular domain might be important in autoimmune mechanism of Graves' disease.