ESPE Abstracts

Background: Thyroid dysfunction is well-established feature in children with Down syndrome (DS). There are several reasons for both clinical (CH) or subclinical (SH) hypothyroidism in these children- thyroid dysgenesis and dyshormonogenesis early in life, thyroid insensitivity to TSH; or autoimmune disease during school age.

Objective and hypotheses: Evaluation of thyroid function in children with DS.

Method: Thyroid function from 80 children with DS was evaluated. The cohort was divided according age and type of thyroid dysfunction. TSH and T₄ were taken in all, while ultrasonographic evaluation was made if elevated TSH was found. Various developmental tests according age were made in all; re-evaluation was made in the group of SH or when starting the therapy with L-thyroxine.

Results: Impaired thyroid function was found in 25% of patients, from which 3 (3.7%) had congenital hypothyroidism detected on neonatal screening, the remaining 7 (8.7%) developed CH within the first 2 years. SH was noticed in 10 (12.5%) respectively. There was dysgenetic thyroid (hypoplastic, ectopic or unilobulated) in 30% of hypothyroid children. The children with SH were followed up for at least 3 years, of which 4 had improved thyroid function, and in six elevation of TSH and decrease of fT₄ occur where therapy was given. In latter group developmental tests worsen at least 6 months before elevation of TSH; after establishing the therapy they showed better results. According age, there were two peaks of onset of hypothyroidism- one in 2^nd year -mostly children with thyroid dysgenesis, and one in 13^th year of age, where thyroid antibodies were negative in majority of cases.

Conclusion: Thyroid dysgenesis seems to have major role in developing clinical hypothyroidism in children with DS at birth or early childhood. Frequent follow up of thyroid parameters, ultrasonographic finding and developmental tests are needed in order to begin with therapy on-time.