[Transient neonatal hyperthyroidism in the child of a treated hyperthyroid mother. Subsequent appearance of sexual...

Area of Science:

• Pediatric Endocrinology
• Neonatal Medicine
• Genetics and Rare Diseases

Background:

• Neonatal hyperthyroidism can occur in infants of mothers with Graves disease.
• Maternal Graves disease management involves medications like potassium iodide and carbimazole.
• Transplacental passage of maternal thyroid-stimulating antibodies can cause fetal hyperthyroidism.

Observation:

• A newborn female presented with neonatal hyperthyroidism.
• At four months, the infant exhibited precocious puberty, including breast development and advanced bone age.
• Hormonal analysis revealed elevated FSH and estradiol, later accompanied by elevated prolactin, with persistently low LH and TSH.
• Irregular brown cutaneous pigmentation was noted on the neck and trunk.

Findings:

• The infant displayed a complex endocrine profile suggestive of multiple hormonal dysregulations.
• The combination of hyperthyroidism, precocious puberty, and cutaneous pigmentation raised suspicion for McCune-Albright syndrome.
• Persistent low levels of luteinizing hormone (LH) and thyroid-stimulating hormone (TSH) were observed.

Implications:

• This case highlights the potential for complex endocrine and developmental sequelae in infants with neonatal hyperthyroidism.
• The findings underscore the importance of considering rare genetic syndromes like McCune-Albright syndrome in infants with atypical presentations.
• Further investigation is warranted to confirm the diagnosis and guide long-term management strategies for such multifaceted conditions.