Neonatal Presentation of Noonan Syndrome Type 2 with Severe Airway Obstruction and Gastroesophageal Reflux Disease: A Case Report
1
Junior Resident, Department of Paediatrics, Jawaharlal Nehru Medical College and KLEs Dr. Prabhakar Kore Hospital and Medical Research Centre , Belagavi -590010 Email - sireeshareddyvasantha@gmail.com
2
Associate Professor, Department of Neonatology, Jawaharlal Nehru Medical College and KLEs Dr. Prabhakar Kore Hospital and Medical Research Centre , Belagavi- 590010 Email - rambhat79@gmail.com
Received: 2025-10-03
Revised: 2025-10-17
Accepted: 2025-11-18
Published: 2025-11-21
| Background: Noonan syndrome is a heterogeneous RAS-MAPK pathway disorder presenting with craniofacial dysmorphism, congenital heart disease, lymphatic abnormalities, short stature, and variable neurodevelopmental impairment. In neonates, respiratory distress due to airway anomalies and severe feeding intolerance may be early but under-recognized manifestations. Noonan Syndrome Type 2, caused by LZTR1 variants, can exhibit more severe airway symptoms and feeding pathology. Case Report: We describe a term female neonate born via elective caesarean section (38+6 weeks, 2.3 kg) who developed immediate upper airway obstruction requiring CPAP support. Feeding attempts failed, and a nasogastric tube was placed; contrast esophagogram revealed Grade IV gastroesophageal reflux disease (GERD). At 17 days of life, she developed acute respiratory collapse with bradycardia requiring resuscitation and mechanical ventilation. Flexible laryngoscopy confirmed laryngomalacia and tracheomalacia. CT of the neck demonstrated subglottic stenosis and tracheal narrowing (2.1 cm segment). Genetic testing identified a heterozygous pathogenic LZTR1 variant confirming Noonan Syndrome Type 2, along with a VUS in BRPF1 associated with intellectual developmental disorder with ptosis and dysmorphic facies. USG abdomen revealed umbilical granuloma, USG cranium showed bilateral caudothalamic groove cysts, and MRI brain was normal. Despite multidisciplinary NICU care, gastrostomy placement, and ventilatory support, the infant succumbed to progressive respiratory failure. This case represents a rare and severe neonatal presentation of Noonan Syndrome Type 2 with life-threatening airway obstruction and Grade IV GERD. Early genetic evaluation, aggressive airway assessment, and coordinated multidisciplinary management are critical in neonates presenting with unexplained respiratory distress and feeding failure.
Noonan Syndrome Type 2, LZTR1, Neonate, Airway Obstruction, GERD Grade IV, Tracheomalacia, Subglottic Stenosis