Ten-years longitudinal study of thyroid function in children with Down syndrome.

Background: Children with Down syndrome (DS) show an increased prevalence of thyroid disease when compared with the general population. The risk for thyroid dysfunction rises with age. A yearly thyroid screening was suggested in the guidelines of the American Academy of Pediatrics for the health supervision of children withDS.Objective and hypotheses: The aim of our investigation is to longitudinally study the thyroid function in children with DS in order to identify the prevalence of thyroid pathology throughout development.Methods: Thyroid function tests were yearly carried out on 120 children with DS, all followed from birth to 10 years of age. There were 65 boys and 55 girls. Subjects were annually classified according to thyroid function as: normal, congenital hypothyroidism (C-HT), hypothyroidism (HT - TSH >10 mcIU/ml and low FT4), subclinical hypothyroidism (S-HT - TSH between 5 and 10 mcIU/ml and normal FT4), hyperthyroidism (HyperT).Results: In our study population the prevalence of normal thyroid function significantly decreased from 90.8% to 41.7% throughout 10-years follow-up. Therefore, the prevalence of thyroid dysfunctions increased, in particular the HT ones. The abnormal findings were almost equally distributed between the genders.Conclusions: More than half of the children with DS in our study developed thyroid dysfunctions. Our results confirm that DS patients, especially those with normal thyroid function and subclinical hypothyroidism, should be carefully followed annually to precociously identify the appearance of thyroid pathology and to begin an adequate hormonal treatment.presentation)