A 45-year-old patient shows marked cognitive impairment that has developed progressively over several months. A family member reports the patient's father had early-onset dementia

Question

What research-based information can be given to the family in response to their concerns about the patient developing early-onset dementia? a. The risk for developing the condition is about 50% only if both parents were affected.
b. The greatest risk exists for relatives of individuals diagnosed with Alzheimer disease before age 55 years.
c. Added risk is present only for people with Down syndrome, so relatives without Down syndrome are essentially safe.
d. Results of the research on genetic predisposition and its effect on the development of early-onset dementia are still unclear.

Answer 1

B
The risk for development of Alzheimer disease (AD) is greater for relatives of people with the illness than it is for those with no family history of AD. An individual with one parent with early-onset AD has a 50% chance of developing it before the age of 55 years as well. Those offspring who do not inherit early-onset AD do not pass it on to their own children and presumably have the same risk of developing AD much later in life as does the general population. Down syndrome does appear to be a risk factor for early-onset AD