Familial Ascending Aortic Aneurysm in a Child With a Pathologic Variant of the Lysyl Oxidase Gene

The lysyl oxidase (LOX) gene encodes the extracellular enzyme lysyl oxidase, which is essential for cross-linking collagen and elastin, key structural proteins that maintain connective tissue stability. Pathogenic variants in the LOX gene are associated with familial thoracic aortic aneurysms. A five-year-old male presented to the emergency room with upper respiratory tract symptoms. A chest radiograph showed a markedly enlarged mediastinum. Further studies revealed a 9-cm thoracic aortic aneurysm confined to the ascending aorta. The child underwent successful surgical intervention.