Question

Which of the following is true for the association of ApoE and Alzheimer disease?

A ε4 is over-represented in samples of affected individuals
B ε4 is associated with an earlier age of onset
C Genetic screening for the ε4 allele is performed to identify those at risk of Alzheimer disease
D A and B
E All of the above

Answer 1

The ε4 allele of ApoE is associated with an increased risk of Alzheimer's disease, is over-represented in affected individuals, and is linked with an earlier age of onset. Genetic testing for ε4 can identify individuals at risk.

Step-by-step explanation:

In addressing the association between ApoE and Alzheimer's disease, the following statements are true:

• ApoE ε4 allele is over-represented in samples of affected individuals.
• The ε4 allele is associated with an earlier age of onset of the disease.
• Genetic screening for the ε4 allele is performed to identify those at risk of Alzheimer disease; however, the presence of the ε4 allele does not guarantee that an individual will develop the disease.

Thus, the correct answer to the student's question is E, 'All of the above.' ApoE ε4 is indeed linked to Alzheimer's disease as an increased risk factor and is associated with both an over-representation in affected individuals and an earlier age of onset. Genetic screening can identify risk but does not necessarily predict disease with certainty.