Association of Hashimoto's thyroiditis with cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) and inducible co-stimulator (ICOS) genes in a Kuwaiti population.

Analysing two CTLA-4 markers [exon 1 A49G single nucleotide polymorphism (SNP) and exon 4 3'UTR (AT)n repeat] and the ICOS intron 4 (GT)n marker for their potential association with HT, and exploring the effect of the tested SNPs on the CTLA-4 isoform expression at the mRNA and protein levels. Total of 270 age-gender-ethnically matched subjects were genotyped by fluorescent-labelled restriction fragment length polymorphism, multiplex PCR, and fragment analysis. Sequencing was used to confirm the genotyping results.