CTLA-4 promoter polymorphisms are associated with latent autoimmune diabetes in adults

The cytotoxic T lymphocyte antigen-4 (CTLA-4) molecule is an important regulator of T-cell activation and a susceptibility candidate for autoimmune diseases. To evaluate the impact of CTLA-4 promoter allelic variants of the CTLA-4 gene in latent autoimmune diabetes in adults (LADA), the MH30 (rs231806), -1147 (rs16840252), and -318 (rs5742909) single nucleotide polymorphisms (SNPs) were studied in a population of Estonian origin, including 61 LADA patients and 230 controls. The MH30 GG genotype (p = 0.0051) and the G allele (p = 0.0023) were significantly associated with LADA. The frequency distribution of alleles and genotypes of rs16840252 and rs5742909 SNPs were not significantly different between the patient and control groups. The frequency of the CTLA-4 GCC (p = 0.000073) haplotype was significantly higher in LADA patients, whereas the frequency of the CTLA-4 CCC (p = 0.0019) was significantly lower in LADA patients in comparison with the control group. The current study confirms the involvement of CTLA-4 gene promoter polymorphisms in the susceptibility of LADA and extends our previous findings of associations with other CTLA-4 polymorphisms.