A common CTLA4 polymorphism confers susceptibility to Autoimmune Thyroid Disease in celiac children

BACKGROUND: Cytotoxic T-lymphocyte-associated protein 4 (CTLA4) is a strong candidate gene in autoimmunity susceptibility. In particular, the CTLA4 CT60 A/G dimorphism has been associated with celiac disease (CD) and was reported to be strongly associated with autoimmune thyroid disease (AITD). AIMS: This study aimed to investigate the possible influences of the CTLA4 CT60 A/G polymorphism in the susceptibility of Italian children to CD and in the predisposition to develop AITD in children with CD. PATIENTS AND METHODS: We genotyped 317 Italian celiac children, including 44 patients (13.9%) who developed AITD after CD diagnosis and 350 controls. RESULTS: The CTLA4 CT60 GG genotype distribution did not show any significant difference between children with CD and control population (p=0.4). On the contrary, the frequency of the GG genotype was significantly higher in patients with CD complicated with AITD than in control subjects (p=0.002) and CD patients without AITD (p=0.02). CONCLUSION: Our data show a significant effect of the CTLA4 CT60G allele at the homozygous state on the risk of developing AITD in children with CD and suggest that the reported association of the CTLA4 CT60 A/G polymorphism with CD is limited to the subgroup of patients who are or will be complicated with AITD.