Which two findings are major diagnostic criteria for Marfan syndrome?

• A. Ectopia lentis and aortic root dilation
• B. Cardiac arrhythmias and pulmonary hypertension
• C. Renal cysts and short stature
• D. Hyperextensible joints and craniosynostosis

Answer: (A)

In Marfan syndrome, the most specific findings used to make the diagnosis are problems in the eyes and the aorta. Ectopia lentis, where the lens is displaced, and dilation of the aortic root are classified as major diagnostic criteria. The lens displacement reflects a direct connective tissue defect from fibrillin-1, and aortic root dilation signals weakness of the aortic wall, both of which are hallmark features of this condition. Together, these two findings strongly point to Marfan syndrome.

The other options describe features that can occur in various conditions or as non-specific findings, but they are not the defining major criteria for Marfan syndrome. Cardiac arrhythmias and pulmonary hypertension aren’t primary diagnostic hallmarks; renal cysts and short stature aren’t characteristic main criteria; and hyperextensible joints with craniosynostosis don’t fit the typical Marfan profile.