Thyroid axis dysfunction in patients with Prader‐Willi syndrome during the first 2 years of life

Abstract

Introduction: Prader-Willi syndrome (PWS) is a genetic disorder caused by the loss of expression of paternally transcribed genes in a highly imprinted region of chromosome 15q11- 13. The clinical phenotype has been well characterized, mostly related to hypothalamic dysfunction. Even though central hypothyroidism has been documented in 20 to 30% of PWS patients, thyroid function during the first 2 years of life has not been clearly defined. Objective: to evaluate hypothalamic-pituitary-thyroid function in infant PWS patients. Study design: Eighteen PWS patients, aged 0.16 to 2 years, were included in a prospective study. PWS diagnosis was based on clinical features and molecular analysis. Serum total (T) T4, free (F) T4, T3, and TSH were evaluated in the PWS patients included in the study. Serum hormone values were compared to those of a large reference population of the same age. Results: In 13 out of 18 PWS patients (72.2%), serum TT4 and/or FT4 levels were below the 2.5th percentile of the reference population, while in only one PWS patient serum T3 were below this cutoff. Conclusion: The results of this study suggest that transient or definitive TRH-TSH thyroid axis dysfunction may frequently be present in infant PWS patients. Pediatricians should be aware of this dysfunction in this critical period of thyroid hormone action on neurological development.