ESPE Abstracts

Inflammation is a known feature of Down syndrome (DS) and is caused by a dysregulation between pro and anti-inflammatory cytokines. Hashimoto's thyroiditis (HT) is characterised by a slowly developing persistent inflammation of the thyroid gland which frequently leads to hypothyroidism. In DS children, HT is the most common autoimmune disease ad its prevalence has been reported to be more elevated than that generally seen in age-matched patients without DS: 34% vs 1.3%, respectively. The diagnosis of HT is based on dysthyroidism and/or presence of antibodies against thyroid peroxidase and thyroglobulin, although seronegative forms can be seen in 5%–10% of cases. The ultrasound features of HT include decreased echogenicity, heterogeneity, hypervascularity, and presence of small cysts. Adequate blood levels of omega-6 (linoleic and arachidonic acid) and omega-3 (EPA and DHA) polyunsaturated fatty acids (PUFAs) may play a protective role against inflammation as they inhibit leukocyte chemotaxis and pro-inflammatory cytokine production. In this cross-sectional study we investigated DHA levels in a case series of pediatric DS patients and explored any correlations with HT. Twenty-six patients with chromosome 21 free trisomy karyotype aged 0-18 years were enrolled. Patients with congenital and isolated subclinical hypothyroidism were excluded. For each patient, a capillary blood sample was analyzed using the "Nexis GC-2030 gas chromatography" method to verify the PUFAs profile. Thyroid function (TSH, FT4, and anti-thyroid antibodies) and the presence of ultrasound signs of HT were assessed in all patients at the time of sampling. Clinical symptoms and/or signs of HT on ultrasound were present in 10/26 subjects (38%; 60% F) who had positive antibodies against thyroid peroxidase and thyroglobulin also, and required Levo-thyroxine replacement therapy (mean age 9 yr ± 68 mo). One subject had ultrasound signs of thyroiditis without circulating antibodies and was euthyroid, and further 2 subjects (8%) had hyperthyroidism at onset of HT requiring treatment with Methimazole. Mean DHA percentage was 1.5% (0.34-2.86), in females (N: 14) 1,37% (0.34-2.58) and in boys (N: 12) 1.6% (0.61-2.86). No significant differences related to age and BMI. DHA levels were negatively correlated with the presence of HT (95% confidence interval 0.67-1.56; t-test P <0.001) in the entire population. HT was confirmed to be a frequent endocrinopathy in DS and was associated with lower DHA levels compared with euthyroidism and absence of autoimmunity. We hypothesize that DHA intake could play a protective anti-inflammatory role by preventing or delaying the onset of HT in DS.