Mosaic Trisomy 16 in a Preterm Newborn with Intrauterine Growth Restriction, Hypoglycemia and Atrial Tachycardia

Trisomy 16, responsible for 1%-2% of first trimester losses, poses diagnostic dilemmas in reproductive medicine. While total trisomy 16 is typically lethal, mosaic trisomy 16 cases exhibit diverse phenotypes, often featuring intrauterine growth retardation and cardiac anomalies. Postnatal survival with high levels of mosaic trisomy 16 is rare, with most affected pregnancies ending in spontaneous abortion between 8 and 15 weeks of gestation. However, recent data suggest that select prenatally diagnosed mosaic trisomy 16 patients manifest a mild phenotype and favorable outcomes. Confined placental mosaicism, commonly detected during chorionic villus sampling, emphasizes the complicated nature of this condition. We present a case of mosaic trisomy 16 in a neonate with atrial tachycardia, emphasizing the complexities and treatment strategies in pediatric care. Notably, our management approach involved the novel use of ivabradine alongside propranolol. This case highlights the imperative for ongoing research and collaborative efforts to deepen our understanding and tailor care for the diverse clinical spectrum of mosaic trisomy 16, ensuring comprehensive monitoring and support for affected individuals.