A 35 year old athlete has height 184 cm., arm span 194cm., pulse rate 64/min., BP148/64 mm Hg. Chest ausultation reveals long diastolic murmur over right 2nd intercostal space on routine examination. The probable diagnosis is –

**Core Concept**
Marfan syndrome is a genetic disorder affecting the body's connective tissue, leading to cardiovascular, skeletal, and ocular manifestations. It is characterized by tall stature, arm span exceeding height, and aortic root dilatation, which can cause aortic regurgitation.

**Why the Correct Answer is Right**
In Marfan syndrome, the aortic root is dilated due to mutations in the FBN1 gene, which encodes the protein fibrillin-1. This leads to the disruption of elastic fibers in the aortic wall, causing aortic regurgitation. The long diastolic murmur heard over the right 2nd intercostal space is characteristic of aortic regurgitation. The patient's tall stature and arm span exceeding height are also classic signs of Marfan syndrome.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it does not match the clinical presentation of Marfan syndrome.
**Option B:** This option is incorrect as it is not a characteristic finding in Marfan syndrome.
**Option C:** This option is incorrect as it is not a common association with Marfan syndrome.

**Clinical Pearl / High-Yield Fact**
Marfan syndrome is associated with a higher risk of aortic dissection and rupture, which can be life-threatening. Therefore, patients with Marfan syndrome require regular echocardiographic monitoring of the aortic root and prompt treatment of any aortic dilatation.

**Correct Answer:** A. Marfan syndrome.

✓ Correct Answer: A. Aoic regurgitation