Analysis of mutations in exon 1 of the human thyrotropin receptor gene: High frequency of the D36H and P52T polymorphic variants

The aim of the present study was to investigate the N-terminal part (the tr anslated part of exon 1) of the human thyrotropin receptor (TSHR) for the p resence of mutations. Patients with Graves' disease (n = 160) and healthy c ontrols (blood donors; n = 140) were screened using single-stranded conform ational polymorphism (SSCP) in combination with restriction enzyme digestio n for the two previously known mutations in this part of the receptor, viz. D36H and P52T TSHR-variants. We did not find any novel mutation in this re gion. However, D36H and P52T variants were found both in the TSHR of Graves ' patients and in the healthy controls. The overall frequency of the D36H-r eceptor variant was 5.0% (15/300) and of the P52T-receptor, 7.3% (22/300). There was no major difference in the frequency for either of the TSHR allel es between the 2 groups. Thus, these 2 polymorphic variants of the TSHR see m to occur in a relatively high frequency in the population.