A novel homozygous thyroglobulin gene variant presenting with massive congenital goiter and neonatal airway obstruction.

Congenital hypothyroidism due to thyroid dyshormonogenesis is a rare inherited disorder that may present with goiter of variable severity. Massive congenital goiter causing life-threatening respiratory distress at birth is exceptionally uncommon. We report a late-preterm male neonate who presented immediately after delivery with severe respiratory failure requiring endotracheal intubation due to critical tracheal compression caused by a massive congenital goiter. Postnatal imaging revealed marked thyroid hyperplasia with airway narrowing. Thyroid function tests demonstrated isolated low free thyroxine (fT4) levels with normal thyroid-stimulating hormone (TSH), a pattern attributed to non-thyroidal illness syndrome related to perinatal asphyxia and inotropic support. Therapeutic-dose levothyroxine was initiated, resulting in a progressive reduction in goiter size and successful extubation. Genetic analysis using next-generation sequencing identified a previously unreported homozygous missense variant in the thyroglobulin gene, supporting the diagnosis of thyroglobulin-related dyshormonogenetic congenital hypothyroidism. This case highlights that congenital goiter should be considered in neonates presenting with respiratory distress at birth, even in the absence of elevated TSH levels or prenatal findings. It underscores the importance of early diagnosis, genetic evaluation, and timely levothyroxine therapy to prevent airway compromise and ensure favorable outcomes.