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Cause of Alzheimer's Disease: What is it really?
 Cause of
Alzheimer's disease overview:
The true cause of
Alzheimer's disease has still not been determined in spite of all the
tremendous advances in understanding the disease process which has
been developed over the past decade. It is believed by many experts
that the cause of Alzheimer's disease may be related to a single
factor in many cases, while others state a variety of factors may
interact in various ways to promote the disease. Being elderly is
still the strongest risk factor in predicting Alzheimer's disease,
along with individuals with Downs Syndrome, a family history of
dementia, and the presence of a specific form (e4) of the gene that
develops into a certain protein called apolipoprotein E, or APOE.
Research into the
cause of Alzheimer's disease has focused on specific forms of the
protein apolypoprotein E (APOE.), called APOE e4, which appears to
play a role in the formation of amyloid plaques. Some experts into
the cause of Alzheimer's claim APOE e4 is linked with an increased
risk of an earlier onset of Alzheimer's disease. An individual with
two copies of APOE e4 (which seems to be approximately 3% of the
Caucasian population) may have a 50% chance of developing Alzheimer's
disease by the age of 80. However, just because you have an increased
risk level, does not guarantee that you will later develop the
illness. Also, the absence of APOE e4 in a blood sample cannot
predict who will get Alzheimer's disease. It is believed that a
person can have APOE e4 and never get the disease.
Is the cause of Alzheimer's disease related to gender?
While it is not
believed that gender is a cause of Alzheimer's disease, women are at a
higher level of risk than men, along with several other illnesses such
as the cardiovascular disorders, high blood pressure and heart attack,
which are also possible risk factors in developing the disease. Other
potential triggers that had been considered to possibly contribute to
the cause of Alzheimer's disease include immune system malfunctions,
and endocrine (hormonal) disorders, slow-acting viruses and toxins.
What role does heredity play as a possible cause of Alzheimer's
disease?
While it is not
considered to be the cause of Alzheimer's disease, it is believed that
heredity plays a significant role in its development. It is believed
that a handful of Alzheimer's disease patients (probably less than 3%)
have a strong genetic predisposition to the disease. In some
families, Alzheimer's disease is carried as a dominant trait (which
means that approximately half of the offspring will inherit the
disorder) on one of three separate chromosomes (1, 14, and 21).
Convoluting these findings however, is a recognition that in some
families, genetic indicators are found both in Alzheimer's disease
patients and their families with no apparent symptoms. Therefore,
environmental risk factors are believed to have a strong effect when
combining environmental risk factors with an individual's genetic
makeup to either cause Alzheimer's disease, or increase the chances
that they may develop it. Also, the same causative factors seem to be
recognized in the development of Alzheimer's disease earlier in life.
In a study of identical twins who share the exact same DNA, the age of
onset of Alzheimer's disease vary by as much as 15 years. In the
future, we will probably need to study people of various different
ethnic, racial, and social groups in order for scientists to discover
the full range of additional risk factors. These findings could
eventually provide new insights into the actual cause of Alzheimer's
disease or possibly what environmental factors may trigger underlying
genetic predispositions.
Some information from The Johns
Hopkins Medical Guide to Health After 50
Additional information and
webpage by Paul Susic MA Licensed
Psychologist Ph.D. Candidate
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