Thrombospondin domain1-related congenital chylothorax in an infant with maple syrup urine disease: a challenging case

Abstract Objectives Congenital chylothorax is a rare entity with various etiologies ranging from anatomical to genetic causes. If associated with non-immune hydrops fetalis mortality rates can reach up to 98%. Treatment is challenging and mostly supportive, with no standard guidelines. Case presentation We describe the unique and challenging course of a late preterm infant with non-immune hydrops fetalis (NIHF), and recurrent chylothorax attributed to homozygous mutations in thrombospondin domain1 (THSD1) gene. The infant was also affected with maple syrup urine disease (MSUD), which further complicated the clinical course. Treatment was supportive by means of chest tubes, intubation, mechanical ventilation, and eventually he was tracheostomized and discharged home on home BiPAP ventilation and required prolonged use of octreotide to prevent re-accumulation of chylothorax. Conclusions THSD1 gene has a role in vascular permeability and its mutation in our patient caused congenital chylothorax and NIHF and is also associated with other features such as vascular malformations.