Background: Autoimmune diseases have a higher incidence and prevalence among the individuals with Down syndrome (DS) compared to chromosomally normal people (increased risk for thyroid, gut and islet autoimmunity, juvenile idiopathic arthritis) These findings provide insights into a very aggressive phenotypic expression of autoimmunity in DS children.
Objective and hypotheses: To investigate for the 1st time whether the association with DS might per se modify the aggregation of extra-thyroidal autoimmune diseases (ETADs) in children with the same index autoimmune disorders, by conditioning a different clustering in the cases with associated DS versus those without DS.
Method: In the present cross-sectional study covering 832 children with autoimmune thyroid diseases (AITDs), we investigated the clustering of ETADs in 2 groups of patients with or without DS (Groups A and B, respectively). All the included patients were screened for the most common pediatric ETADs by specific anamnesis, clinical examination and some selected autoantibody assays.
Results: The rate of children with no associated ETADs was much higher in Group B, whilst the rates of children with at least one or more associated ETADs were significantly higher in Group A. Moreover, the epidemiological distribution of the associated ETADs was significantly different in the 2 patient groups with or without DS; in particular, alopecia areata (P=0.00001), vitiligo (P=0.00001) and celiac disease (P=0.0004) were more often found in group A, whilst the distribution of T1 diabetes mellitus was not different.
Conclusion: In a study population of children and adolescents with AITDs the association with DS might be able to: a) condition an increased risk of developing ETADs; b) modify the clustering of ETADs, which is generally observed in the children with AITDs but without DS, by favouring the aggregation of alopecia areata, vitiligo and celiac disease.
10 - 12 Sep 2016
European Society for Paediatric Endocrinology