CTLA-4 Polymorphism in Children with Down Syndrome and Autoimmune Thyroid Diseases

Abstract

This study explored the association between the CTLA-4 polymorphism and thyroid function parameters in children with Down syndrome (DS). A cross-sectional study involving children aged 1 month to 5 years diagnosed with DS was conducted from February to November 2020 at Dr. Soetomo General Hospital, Surabaya, Indonesia. The subjects were recruited consecutively, and if they presented critical or severe illness, they were excluded. A medical history and physical examination was performed to obtain the sociodemographic and clinical characteristics of subjects. A blood sample was obtained to test thyroid function. This test consisted of anti-TPO, anti-TG, TSH, T3, and fT4. The CTLA-4 CT60 polymorphism was analyzed from peripheral blood mononuclear cells using polymerase chain reaction–restriction fragment length polymorphism. The majority of subjects were 1 to 5 years of age (81%); 83.3% suffered from central hypothyroidism, and 16.7% primary hypothyroidism. Almost two-thirds of subjects were positive for anti-TPO (65%), and more than four in five were positive for anti-TG (86%). Most had low TSH levels (88.1%). The CTLA-4 CT60 polymorphism significantly correlated with T3 (p = 0.049; r = 0.480 in CT-60; p = 0.046; r = 0.29 in CT-1822). A significant association was found between the CTLA-4 A/G and G/G genotypes with a higher proportion of low TSH levels among DS patients with hypothyroidism. This study showed the potential influence of CLTA-4 on thyroid function in children with DS.