What characteristic differentiates Marfan syndrome from homocystinuria?

Marfan syndrome is characterized by features related to connective tissue abnormalities, one of the most notable being aortic root dilation. This dilation can lead to serious cardiovascular complications such as aortic regurgitation and aortic dissection. Individuals with Marfan syndrome often present with other cardiovascular issues, tall stature, long limbs, and hyperflexible joints, but aortic involvement is a hallmark feature.

In contrast, homocystinuria, a metabolic disorder caused by cystathionine beta-synthase deficiency, does not primarily present with aortic root dilation. Instead, it often manifests with intellectual disabilities, thromboembolic events, and skeletal abnormalities, but the cardiovascular manifestations typically lack the same prominent aortic involvement seen in Marfan syndrome.

Thus, aortic root dilation serves as a critical differentiating factor between Marfan syndrome and homocystinuria, highlighting the distinctive pathophysiological mechanisms and clinical presentations associated with each condition.