Thyroid hormone levels in children with Prader-Willi syndrome: A randomized controlled growth hormone trial and 10-year growth hormone study

Abstract

Context: Several endocrine abnormalities were reported in children with Prader-Willi syndrome (PWS), including hypothyroidism. Growth hormone (GH) treatment may impact the thyroid hormone axis by direct inhibition of T4 or TSH secretion or by increased peripheral conversion of free T4 (FT4) to T3. Objective: The objective of this study is to evaluate thyroid function during GH treatment in a large group of children with PWS. Methods: Serum FT4, T3, and TSH are measured in a 2-year randomized controlled GH trial (RCT) and 10-year longitudinal GH study (GH treatment with 1.0 mg/m²/day [∼0.035 mg/kg/day]). Results: Forty-nine children with PWS were included in the 2-year RCT (median [interquartile range, IQR] age: GH group 7.44 [5.47-11.80] years, control group 6.04 [4.56-7.39] years). During the first 6 months, median (IQR) FT4 standard deviation score (SDS) decreased in the GH group from -0.84 (-1.07 to -0.62) to -1.32 (-1.57 to -1.08) (P