Graves' disease in a five-month-old boy with an unusual treatment course.

This case describes the youngest child to date to be diagnosed with endogenous GD and to successfully undergo definitive treatment with thyroidectomy. An underlying defect in mitochondrial function is suspected, suggesting a potential novel pathophysiologic link to early-onset thyroid autoimmunity. Additionally, this case illustrated the development of impaired pituitary sensitivity to TH following thyrotoxicosis of postnatal onset, which may contribute to our understanding of hypothalamic-pituitary-thyroid (HPT) axis development.