Clinical characteristics of polyglandular autoimmune syndromes in pediatric age: an observational study.

Objectives: Polyglandular autoimmune syndromes (PAS) are characterized by the association of two or more autoimmune diseases (AID) and are classified into four types. PAS type 1 is more frequently manifested in childhood, but the prevalence of other PAS in children, less described in the literature, seems to be underestimated.

Methods: This study aimed to evaluate the prevalence of PAS in a selected pediatric population of 879 children with Diabetes mellitus type 1 (DM1), autoimmune thyroid disease (AITD), and Addison's disease (AD) followed in our hospital for 10 years and describe and classify the manifestations of different PAS.

Results: We diagnosed 35 children with PAS, most fulfilled criteria for PAS type 3 (65.7%), and AITD was the AID more frequently detected (74.3%). PAS type 1 was not diagnosed in our sample. Patients with PAS manifested DM1 and AITD at a younger age than children with monoglandular pathology (7.7 vs. 9.3 years, p=0.04 and 7.7 vs. 13.1 years, p<0.01).

Conclusions: This is the first study that analyzes the prevalence of different types of PAS in a pediatric population followed by endocrine pathologies, namely DM1, AD, and AITD. As PAS manifestations are often preceded by a long latency period characterized by the presence of autoantibodies, we reinforce the need to value these markers for timely diagnosis and to screen PAS in patients with AD throughout their lives.