What are Alzheimer\'s Disease and its Genetic Causes?

What are Alzheimer's Disease and its Genetic Causes?

Alzheimer's Disease and Genetics

Dementia; It is the deterioration of memory, speech, problem solving and other thinking abilities at a level that affects daily life. The most typical finding in Alzheimer's disease (AD) is dementia. Dementia usually starts mildly and later on, the patient becomes unable to do his daily work. Death often results from inactivity, malnutrition, and pneumonia.


  • Forgetfulness
  • Confusion
  • Decreased ability to judge and relate
  • Speech disorder
  • Vision complaints
  • Agitation (inconsistent excessive behavior)
  • Withdrawal (behavior and personality changes)
  • Hallucinations

95% of Alzheimer's disease occurs over 60-65 years of age (late-onset Alzheimer's disease), 5% occurs under 60-65 years of age (early-onset Alzheimer's disease).

Risk factors:

  • Familial predisposition
  • Late-onset Alzheimer's disease
  • Early-onset Alzheimer's disease
  • Down Syndrome
  • Multiple effects: advanced age, female gender, chronic diseases, infections

Genetic causes:

  • About 25% of Alzheimer's disease is familial.
  • Genetic causes account for <2% of late-onset familial Alzheimer's disease.
  • In early-onset familial Alzheimer's disease, mutations (errors) in APP, PSEN1 and PSEN2 genes are found in 60-80% of patients.
  • <1% is due to Down syndrome.

Genetic predisposition


  • Early-onset Alzheimer's disease
  • Alzheimer's disease in 3 or more people in the family

if any, the patient should be evaluated by a Medical Genetic physician and receive genetic counseling.