Association of a CTLA-4 3′ untranslated region (CT60) single nucleotide polymorphism with autoimmune thyroid disease in the Japanese population

The etiology of the autoimmune thyroid diseases (AITDs), Graves' disease (GD) and Hashimoto's thyroiditis is largely unknown. However, genetic susceptibility is believed to play a major role. The cytotoxic T-lymphocyte antigen-4 (CTLA-4) gene, encoding a negative regulator of the T-lymphocyte immune response, had been reported to be associated and/or linked to AITD. Recently, AITD susceptibility in the Caucasians was mapped to the 6.1-kb 3'UTR of the CTLA-4 gene, in which the single-nucleotide polymorphism(SNP), CT60, was most strongly associated with AITD. In order to determine the association of the CTLA-4 gene with AITD in the Japanese, case-control association analysis for the CT60 of the CTLA-4 gene using 264 AITD patients and 179 healthy controls was done. The frequency of the disease-susceptible G allele of the CT60 of the Japanese control was higher than that of the Caucasians (72.6 vs. 52.3%). However, the Gallele of the CT60 was associated with GD(84.0 vs. 72.6%, P=0.0008) and AITD(80.1 vs. 72.6%, P=0.009) in the Japanese. Furthermore, the Gallele of the CT60 was associated with the increased risk for GD [P=0.004; odds ratio (OR)=2.0] and AITD (P=0.03; OR=1.6) in a recessive model. These results suggested that the CTLA-4 gene is involved in the susceptibility for GD and AITD in the Japanese.