Introduction
The chromosomal alteration in Down syndrome confers susceptibility to immune dysregulation including autoimmunity and immunodeficiency. We aim to describe clinical and immunological characteristics of patients with autoimmune thyroiditis and trisomy 21.
Methods
It is an observational, retrospective, cross-sectional and descriptive study based on records from the National Institute of Pediatrics, involving patients diagnosed with trisomy 21 and autoimmune thyroiditis from January 2012 to December 2021. For quantitative variables, mean, standard deviation and quartiles were used; frequencies and percentages were used for qualitative variables.
Results
The mean age was 14.25 years. Clinical manifestations of thyroid disease included hypothyroidism in 90%, 5% experiencing both hypo and hyperthyroidism during the course of the disease, and 5% presenting hyperthyroidism.
40% exhibited another manifestation of autoimmunity in addition to autoimmune thyroiditis, of which 12.5% had alopecia areata, 25% had vitiligo, 15% had celiac disease, 2.5% juvenile idiopathic arthritis, and 2.5% has vasculitis. 12.5% of patients presented onychomycosis.
In the biochemical evaluation, 17.5% of patients showed elevated levels of anti-thyroglobulin antibodies, and 77.5% had elevated anti-thyroid peroxidase antibody values above the normal range; 17.5% of patients had both autoantibodies elevated. The highest levels of autoantibodies were recorded in patients with hypothyroidism (70%). 40% exhibited lymphopenia at the diagnosis of autoimmune thyroiditis.
Conclusions
The studied population aligns with global literature in that hypothyroidism is the most common initial presentation with a similar gender distribution. However, this cohort differs in having elevated anti-thyroglobulin and anti-thyroid peroxidase antibody titers at the time of diagnosis.
The two pathologies most frequently associated with the coexistence of Down syndrome and autoimmune thyroiditis were alopecia areata and vitiligo. One-third of the studied population exhibited positive serologies for other autoimmune diseases, most notable celiac disease.
