Thyroid Dysfunction in Down Subjects: A 25 Years Follow up

Presentation Number: SAT-0552
Date of Presentation: June 21st, 2014

Ines Bucci*, Sandra Melanzi, Luca Damiani, Camilla Tinari, Cesidio Giuliani and Giorgio Napolitano
University of Chieti-Pescara, Chieti, Italy

Abstract

Down subjects are at increased risk for both neonatal and adult thyroid dysfunction. Up to 30% of patients with trisomy 21 suffer from hypothyroidism; most of them have chronic autoimmune thyroiditis (CAT), however, increased level of TSH without autoimmunity is not an unusual finding.  Focus of our study has been the evaluation of thyroid function and autoimmunity in Down subjects during a 25 years follow up. 190 subjects (67F, 123M, age 0.5-40 years) have been studied. At first observation thyroid status of the whole cohort was classified as follows: 118 euthyroidism; 6 congenital hypothyroidism; 14 CAT; 2 Graves’ disease; 6 subclinical hyperthyroidism and negative TSHr-TPO autoantibodies (TPOAb-); 44 non-autoimmune subclinical hypothyroidism (TPOAb-). Of the 190 subjects admitted, 107 have been followed up for >5 years (mean follow up 16.1 ± 6.3 years): 72 were younger than 8 yrs old and 3 out of them were TPOAb+ (4.1%); the remaining 35 were > 8 yrs old and 4 out of them were TPOAb+ (11.4%). At first examination 71 were euthyroid, 9 suffered from CAT, 5 from subclinical hyperthyroidism and were TSHrAb- and TPOAb-, 22 from increased TSH levels and were TPOAb-. At the end of the follow up, 46 Subjects (42.9%) were euthyroid, 10 (9.3%) were treated with L-T4, 39 (36.4%) had CAT, 1 (0.9%) suffered from Graves’ disease, 11 (10.3%) had non-autoimmune subclinical hypothyroidism (TPOAb-). Of particular interest is the evaluation of the 27 subjects with non-autoimmune subclinical disease (5 hyper-, 22 hypothyroid) at first visit. 12 (44.4%) were euthyroid at the end of the follow up, 9 (33.3%) developed CAT, 2 (7.4%) started LT-4 treatment because of TSH levels > 10 mUI/L and in 4 (14.8%) non-autoimmune subclinical hypothyroidism was confirmed. Finally, 33 (30.8%) subjects developed thyroid autoimmune disease during the follow up; mean age at first observation of TPOAb+ was 22.7 ± 8.0 years. Our data confirm the increased incidence of thyroid disorders in Down syndrome; they also show that a relevant percentage of subjects with increased TSH level and TPOAb- normalize their TSH with time. More than 30% of these subjects, however, developed thyroid autoimmunity  during the follow up. We finally observed that the mean age at first TPOAb+detection was 22 years, which is significantly lower than in general population, thus confirming the observation that Down syndrome has to be considered as a premature aging syndrome.

 

Nothing to Disclose: IB, SM, LD, CT, CG, GN