From Spine to Syndrome: Incidental Spine MRI Red Flags Leading to <i>PMEPA1</i>-Related Loeys-Dietz Syndrome

A 49-year-old man with prior DeBakey IIIb dissections underwent preoperative spinal MRI for lumbar stenosis, which incidentally showed lumbosacral dural ectasia and bilateral pedicle thinning. Orthopedic review and cross-disciplinary discussion prompted reconsideration of Marfan syndrome (MFS). Under the revised Ghent criteria, the patient did not meet the diagnostic criteria despite a high systemic score (11). Targeted testing identified heterozygous PMEPA1 c.624dup, p. (Ser209Glnfs*3), supporting Loeys-Dietz syndrome with skeletally predominant features. This case illustrates that spine-MRI red flags should prompt Ghent-based re-examination and genetic referral when aortic-root features are absent, and genetic confirmation should guide cascade testing and risk-adapted surveillance of relatives.