ASSOCIATION OF A THYROGLOBULIN GENE POLYMORPHISM WITH HASHIMOTO'S THYROIDITIS IN THE SPANISH POPULATION.

CAPUTO, MARIELA; RIVOLTA, CARINA MARCELA; ESPERANTE, SEBASTIÁN ANDRÉS; MORIES, MARÍA TERESA; CORRALES, JUAN JOSÉ; GONZÁLEZ-SARMIENTO, ROGELIO; TARGOVNIK, HÉCTOR MANUEL; MIRALLES-GARCÍA, JOSÉ. MARÍA

Santiago, Chile

Congreso; XII Congress of Latin American Thyroid Congress (SLAT); 2007

Sociedad Latinoamericana de Tiroides (SLAT)

Objetive The autoimmune thyroid diseases (AITD) are complex disorders caused by a combination of genetic susceptibility and enviromental factors which are believed to initiate the autoimmune response to thyroid antigens in AITD. Identification of the susceptibility genes in AITD has found that unique and diverse genetic factors are in association with Graves disease (GD) and Hashimoto thyroiditis (HT). The thyroglobulin (TG) is an identified thyroid specific gene associated to autoimmune thyroid diseases. The aim of this work was to test for evidence of allelic association between Spanish HT patients and TG polymorphism markers.  Methods We studied six polymorphisms distributed throughout all the TG gene: four microsatellites (Tgms1, Tgms2, TgrI29 and TgrI30), an Indel polymorphism (IndelTG-IVS18) and a SNP (c.7589G>A) in 150 Hashimoto patients compared with 100 non-related normal subjects. Results  No differences in allele and genotype frequencies distribution were observed between HT cases and controls for Tgms1, Tgms2, TgrI30, IndelTG-IVS18 and c.7589G>A systems. However, when analysing the HT patients with the TgrI29 microsatellite we found a significant association between the 199 bp and 201 bp alleles and HT.  The significant increase in the frequency of the 199bp allele was in the HT group (33,3% vs 24,5 in control group) (p=0.0364). In contrast, the major prevalence of the 201 bp allele has been seen in control subjects (47,5% vs 37,7% in HT group) (p=0.0332). The same happened with the homozygous form of the 201bp allele (23% vs 12.6%, controls and HT respectively) (p=0.0385). Conclusions  Our work showed the association between the TG gene and HT in Spanish population and support the described evidence of thyroglobulin as a thyroid-specific AITD susceptibility gene. Identification of additional AITD susceptibility genes would help to understand molecular mechanism by which they induce thyroid autoimmunity.