MCQ – 87781

A 30-year-old man presents for a routine physical examination. The patient is tall (6 ft, 5 in) and has long fingers (shown in the image). One year later, he suffers a dissecting aortic aneurysm. This patient most likely carries a mutation in a gene that encodes which of the following proteins?

Correct Answer � A Explanation

Answer : A Collagen

• Condition described in question is marfan syndrome

• The cause of Marfan syndrome has been established as missense mutations in the gene coding for fibrillin-1.

• Fibrillin is a family of connective tissue proteins analogous to the collagens.

• It is widely distributed in many tissues in the form of a fiber system termed microfibrils. 

• For example, the deposition of elastin on microfi brillar fibers produces the concentric rings of elastin in the aortic wall.

• Collagen gene mutations  are found in patients with Ehlers-Danlos syndrome and osteogenesis imperfecta. 

• Dystrophin gene mutations are found in patients with muscular dystrophy.