Objective: The purpose of this study was to investigate the presence of diabetes, thyroid, and celiac diseases (CD)-related autoantibodies in children with type 1 diabetes (DM1) and their siblings.
Materials and methods: The study population included 57 children with DM1, aged 11.7+/-4.5 years and their 89 healthy siblings, aged 11.0+/-5.4 years. Autoantibodies to glutamic acid decarboxylase (GAD65), islet cell (ICAs), insulin (IAAs), antiendomisial antibody (EMA), thyroid peroxidase, thyroglobulin, and thyrotropin receptor antibodies were studied both in diabetic patients and their siblings.
Results: The frequencies of GAD65, ICAs and IAAs positivity were found to be 63.2, 56.1 and 84.2% in patients with DM1 and 53.9, 24.4 and 3.4% in their siblings, respectively. The frequencies of autoimmune thyroid diseases (ATD) as determined by positive thyroid-related autoantibodies were 38.6 and 21.4% (p=0.024) among patients with DM1 and siblings, respectively. Subclinical hypothyroidism or hyperthyroidism was detected in 5.3% of patients with DM1 but in none of their siblings. EMA was positive in 3.5% of diabetic patients and 1.1% of their siblings.
Conclusions: Our findings supported the view that children with DM1 should be screened annually for ATD. Relatively lower frequency of CD in the present study indicated that screening for CD-related autoantibodies might be postponed to older ages in asymptomatic patients. The present findings also suggested that the screening for diabetes- (especially GAD65) and thyroid diseases-related autoantibodies in siblings may ensure some useful information about the clinical course.