Marfan’s syndrome is a disease associated with faulty manufacture of the extracellular protein fibrillin. Since this is a component of elastin, in which of the numbered cells would the damaged gene be expressed?
The Correct Answer and Explanation is:
Correct Answer: Fibroblast (Cell #2)
Explanation
Marfan syndrome is a genetic disorder caused by mutations in the FBN1 gene, which encodes fibrillin-1, a glycoprotein essential for the formation of elastic fibers in connective tissue. These elastic fibers are critical for the flexibility and strength of tissues such as blood vessels, lungs, skin, and ligaments. Fibrillin is not itself elastin but plays a key role in the structure of microfibrils, which provide a scaffold for elastin deposition and function.
The production of fibrillin and other extracellular matrix proteins, including elastin, is carried out by fibroblasts—connective tissue cells responsible for synthesizing and maintaining the extracellular matrix. Fibroblasts are found in various tissues and are essential for tissue repair and integrity. In the context of Marfan syndrome, the mutated FBN1 gene leads to abnormal or insufficient fibrillin-1 production by fibroblasts, which disrupts the formation of functional elastic fibers and weakens connective tissue throughout the body.
Because the mutation is expressed in fibroblasts, these are the primary cells affected by the faulty fibrillin production. Other cell types, such as neurons, muscle cells, or epithelial cells, do not produce fibrillin-1 and thus would not express the damaged gene in a way that affects elastic fiber synthesis.
The clinical manifestations of Marfan syndrome—including aortic aneurysms, lens dislocation, and long, flexible limbs—are all consequences of weakened connective tissue, primarily due to faulty elastic fiber formation stemming from fibroblast dysfunction. Understanding the role of fibroblasts helps in grasping how a single gene mutation can lead to such widespread systemic effects.
In conclusion, among various cell types, the fibroblast is the correct one where the damaged FBN1 gene is expressed, leading to the symptoms observed in Marfan syndrome.
