Alzheimer's disease has a distinct genetic component, according to WebMD. Scientists have identified four chromosomes that increase an individual's possibility of developing the disease. However, not all individuals who suffer from Alzheimer's possess these chromosomes, while some individuals with the chromosomes never go on to develop the disease.
Although doctors are not certain what causes all cases of Alzheimer's disease, familial Alzheimer's is definitely linked to heredity, reports WebMD. This rare form of the disease, which represents less than 1 percent of cases, affects at least two generations of a family. Symptoms often appear by the time individuals reach their 40s.