Organic Mental Disorders
A 42-year-old woman comes to the psychiatrist with complaints of short-term memory loss. She has lost her way home several times in past weeks. Mini Mental Status Exam scores 18 of 30 points. An MRI shows the loss of brain volume. The patient’s mother died of the same disease at age 46. Which of the following genes in this patient (and her mother) are likely to show a mutation on chromosome 14? (LQ)
|C||β-Amyloid precursor protein (APP)|
|D||Apolipoprotein E (Apo E)|
a. In the case of hereditary Alzheimer disease which appears between the ages of 40 and 50, the presenilin 1 gene, located on chromosome 14, is involved in 70% to 80% of cases.
b. Another 20% to 30% are attributable to the presenilin 2 gene, located on chromosome 1, responsible for hereditable cases of Alzheimer disease appearing at age 50.
c. A final 2% to 3% of Alzheimer cases, which appear after the age of 50, are attributable to the -amyloid precursor protein (APP) gene located on chromosome 21.