Role of Different CD40 Polymorphisms in Graves' Disease and Hashimoto's Thyroiditis

Genome-wide association studies have led to the discovery of several susceptibility genes related to autoimmune thyroid diseases (AITDs). However, controversial results have been reported regarding the role of single-nucleotide polymorphism (SNP) of CD40 in the disease susceptibility. The objective of this study was to identify the relationship of the polymorphisms of three sites of CD40 with the susceptibility to AITD in the Chinese population. We genotyped three polymorphisms of CD40: C/T -1 SNP, 58038T site of the third exon and C64610G site of the ninth exon in 196 GD cases, 121 HT cases and 122 control subjects. The three putative polymorphism sites were amplified by PCR for sequencing and analysis. The genotype frequencies of CD40 -1 C/C genotype and C allele were significantly higher in the GD group than those in normal control. For the C64610G polymorphism, the C/G genotype was significantly more frequent in HT group than in control group, and the G allele frequencies in the GD and HT group were both higher than those in control group. These results indicated that there exist different susceptibility loci for AITD within CD40, each contributing a different effect in the onset and development of AITDs.