[A case report of Refetoff's syndrome]

Area of Science:

• Endocrinology
• Molecular Endocrinology
• Pediatric Endocrinology

Background:

• Generalized resistance to thyroid hormone (GRTH) is a rare genetic disorder characterized by reduced sensitivity of target tissues to thyroid hormones.
• It is typically caused by mutations in the thyroid hormone receptor beta (TR beta) gene.
• GRTH presents with a spectrum of clinical manifestations, including goiter, delayed development, and paradoxical symptoms of hyperthyroidism or hypothyroidism.

Observation:

• An 11-year-old girl presented with diffuse goiter but no thyrotoxic symptoms.
• Elevated serum T4 and T3 levels with normal T3/T4 ratio, normal basal metabolic rate (BMR), and normal TSH response to TRH stimulation were observed.
• Negative autoantibodies and absence of pituitary tumor or visual field defects were noted.

Findings:

• The patient's clinical presentation and laboratory data suggested Refetoff's syndrome, now classified as generalized resistance to thyroid hormone.
• Treatment with high-dose L-thyroxine (450 micrograms/day) for 16 months led to goiter regression and resolution of dysphagia.
• Post-treatment, serum TSH levels decreased significantly, and thyroidal iodine uptake was suppressed, indicating effective hormone replacement.

Implications:

• This case highlights the importance of considering GRTH in pediatric patients with unexplained goiter and thyroid hormone abnormalities.
• Successful management with high-dose L-thyroxine demonstrates its efficacy in normalizing thyroid status and alleviating symptoms in GRTH.
• Further research into the molecular mechanisms and long-term outcomes of GRTH is warranted to optimize patient care.