Tracheal Compression on Chest X-ray Leading to the Diagnosis of Right Aortic Arch in 22q11.2 Deletion Syndrome.

22q11.2 deletion syndrome (22q11.2DS) is a relatively common disorder in pediatrics, frequently presenting with immune dysfunction, cardiac malformations, and hypoparathyroidism, all stemming from the development of the fourth branchial arch. While intracardiac malformations, such as tetralogy of Fallot, are highly prevalent, aortic abnormalities are also common. We report the case of a male diagnosed with 22q11.2DS at 12 years of age. His medical history included neonatal hypocalcemia, developmental delays, and later-onset tetany due to hypoparathyroidism. Despite a normal echocardiogram, a chest X-ray revealed deviation of the right tracheal wall, prompting MRI evaluation that identified a right aortic arch. This report highlights the diverse phenotypic spectrum of 22q11.2DS, demonstrating that significant vascular anomalies originating from the fourth branchial arch, such as right aortic arch, can occur even in the absence of classic intracardiac malformations. It underscores the importance of a comprehensive diagnostic approach, including advanced imaging modalities such as MRI, especially when subtle signs of external tracheal compression are evident on chest X-ray.