Question:medium
Choose the best method of diagnosis for the clinical sign represented in the image.
Choose the best method of diagnosis for the clinical sign represented in the image.
Show Hint
A golden-brown corneal ring points to Wilson's disease - test the copper-carrying protein.
Updated On: Jun 23, 2026
- Serum copper
- Serum ceruloplasmin
- Karyotyping
- PCR
Show Solution
The Correct Option is B
Solution and Explanation
Step 1: Name the sign first. A brownish pigmented rim at the outer edge of the cornea, sitting in Descemet's membrane and starting near Schwalbe's line, is the Kayser-Fleischer ring of Wilson's disease.
Step 2: Link the sign to its biochemistry. Wilson's disease is a recessive defect of the copper-transporting ATPase, so copper cannot be loaded onto ceruloplasmin and is instead deposited in tissues such as cornea, brain, and liver. The direct laboratory consequence is a low circulating ceruloplasmin level.
Step 3: Choose the test. Of the four choices, the one that captures this consequence and is part of the standard Sternlieb criteria is serum ceruloplasmin, making it the best diagnostic method offered.
Step 4: Eliminate the rest. Serum copper alone is unreliable because free and bound fractions move in opposite directions. Karyotyping screens for aneuploidy, irrelevant to a metabolic copper disorder. PCR-based ATP7B genotyping is reserved for confirmation when biochemistry is equivocal, not as the primary test in this list.
\[\boxed{\text{Serum ceruloplasmin}}\]
Step 2: Link the sign to its biochemistry. Wilson's disease is a recessive defect of the copper-transporting ATPase, so copper cannot be loaded onto ceruloplasmin and is instead deposited in tissues such as cornea, brain, and liver. The direct laboratory consequence is a low circulating ceruloplasmin level.
Step 3: Choose the test. Of the four choices, the one that captures this consequence and is part of the standard Sternlieb criteria is serum ceruloplasmin, making it the best diagnostic method offered.
Step 4: Eliminate the rest. Serum copper alone is unreliable because free and bound fractions move in opposite directions. Karyotyping screens for aneuploidy, irrelevant to a metabolic copper disorder. PCR-based ATP7B genotyping is reserved for confirmation when biochemistry is equivocal, not as the primary test in this list.
\[\boxed{\text{Serum ceruloplasmin}}\]
Was this answer helpful?
0
