Introduction:
Introduction: Type III Polyglandular Autoimmune Syndrome (PAS III) is composed of autoimmune thyroid diseases associated with endocrinopathy other than adrenal insufficiency. This syndrome is associated with organ-specific and organ-nonspecific or systemic autoimmune diseases. The frequency of PAS syndromes in diabetic children is unknown.

Objectives:
The aim of the study was to evaluate the incidence of PAS III in children with diabetes mellitus type 1. Patients and methods: The study consisted of 461 patients with diabetes mellitus type 1(T1DM), who were 1-19 years of age. TSH, free thyroxin, TPO autoantibodies, and thyroglobulin autoantibodies were determined annually. Autoimmune Hashimoto’s thyroiditis was diagnosed in children with positive tests for TPO Ab and Tg Ab and thyroid parenchymal hypogenicity in the ultrasound investigation. Elevated TSI antibodies were used to diagnose Graves’ disease. Additionally, Anti-Endomysial Antibodies IgA class were determined every year as screening for celiac disease. During clinical control, other autoimmune diseases were diagnosed. Adrenal function was examined by the diurnal rhythm of cortisol.

Results:
PAS III was diagnosed in 14.5% children: PAS IIIA (T1DM and autoimmune thyroiditis) was recognized in 11.1 % and PAS III C (T1DM and other autoimmune disorders: celiac disease, and JIA, psoriasis and vitiligo) in 3.5% children. PAS IIIA was more prevalent in girls than in boys – 78.4% versus 21.6% (p<0.05). PAS III was observed between 1-5 years of life in 66.6% children; the frequency decreased in consecutive years and successively increased in the adolescence period to 22.7%.

Conclusions:
PAS III occurs in 14.5% of children with DM type1 and the incidence is positively correlated with patients’ age and female gender. Children with PAS III should be carefully monitored as a group at risk for the development of other autoimmune diseases.