A patient with abnormally high iron levels is tested to determine if hemochromatosis, specifically the C282Y mutation in the HFE gene, is the cause. The patient's DNA is isolated from whole blood and amplified. Amplicons are then cut with RsaI, and the resulting fragments are separated by gel electrophoresis. There are no RsaI sites in the normal 250 bp PCR product, while the C282Y mutation generates one RsaI site. The lane containing the patient's sample has three bands at 250 bp, 140 bp, and 110 bp. Controls were acceptable. Which of the following is the correct interpretation of these results?

Question

Quizplus · Accepted Answer

The presence of three bands at 250 bp, 140 bp, and 110 bp indicates that the patient is heterozygous for the C282Y mutation in the HFE gene. The 250 bp band is the normal PCR product, the 140 bp band indicates cleavage of one of the PCR products by RsaI at the mutation site, and the 110 bp band is the result of cleavage of both PCR products by RsaI. This pattern confirms the presence of the C282Y mutation in one allele, which is consistent with hemochromatosis.

A Patient with Abnormally High Iron Levels Is Tested to Determine