Trametinib restores the central conducting lymphatic flow in a premature infant with Noonan syndrome

Key Clinical Message We describe a premature hydropic infant with Noonan syndrome and a therapy refractory chylothorax. This was shown to be due to a central conducting lymphatic anomaly. After therapy with a MEK‐inhibitor the infant recovered clinically and radiologically completely, possibly by restoring lymphatic valve function.