Polymorphisms of HLA Class II Predispose Children and Adolescents with Type 1 Diabetes Mellitus to Autoimmune Thyroid Disease

Abstract

To determine the prevalence of autoimmune thyroid disease (AITD) in children and adolescents with type 1 diabetes mellitus (DM), and assess whether the development of AITD is correlated with specific DQ-A and DQ-B loci of the HLA class II antigens, we analyzed thyroid function using anti-thyroid antibodies and HLA-DQ-A and -DQ-B polymorphisms in 69 patients with type 1 DM, in 75 normal healthy controls, and in 21 patients with AITD but without type 1 DM. Eighteen patients (26%) in the diabetic patients had AITD. In the diabetic patients, DQA1*0301 and DQB1*0302 occurred more frequently than in controls [DQA1*0301: OR=1.939, 95% CI=1.210–3.109 (P=0.008, Pc (corrected P) <0.05); DQB1*0302: OR=2.558, 95% CI=1.354–4.832 (P=0.005, Pc>0.05)]. Compared with controls, non-diabetic subjects with AITD showed higher frequency of DQA1*0301 (Pc<0.05) and DQB1*0601 (Pc>0.05), but these alleles were not contributing factors in the development of AITD in diabetic patients. In diabetic patients, DQB1*0201, known as susceptible allele of type 1 DM was not a contributing factor in the development of AITD in diabetic patients. Unlike DQB1*0201, DQB1*0401 was more frequently found in diabetic patients with AITD than in controls [OR=4.053, 95% CI=1.607–10.221 (P=0.0017, Pc<0.05)] or than in non-diabetic AITD patients [OR=15.769, 95% CI=1.905–130.530(P=0.002, Pc<0.05)]. In non-diabetic subjects, DQB1*0401 did not provide susceptibility for AITD.Our results suggest that HLA DQB1*0401 is a predisposing genetic marker for the development of AITD in patients with type 1 DM in Korea.