Did you know DNA influences your risk of Alzheimer’s Disease?
Would you want to know your chances of developing Alzheimer’s disease, and if you did, would it change your life?
Going, going, gone! There goes your memory and that’s only the beginning. Next, you lose the ability to think and reason, then forget how to cook, read or dance. Finally you don’t remember how to do the basic things like getting dressed or taking a bath. This is the progression of Alzheimer’s disease. Today, over 46 million people around the world are living with Alzheimer’s or other dementias. If that is not daunting enough, this is predicted to reach 75 million by 2030 and 131.5 million by 2050. Alzheimer’s does not discriminate – Ronald Regan, Norman Rockwell and Rosa Parks all died from Alzheimer’s.
Alzheimer’s disease (AD) was named after the German physician, Alois Alzheimer, who first made the connection between memory-loss and changes in the brain. The brain of an Alzheimer’s patient is smaller, has fewer nerve cells, and has many abnormal structures called plaques and tangles. Late-onset Alzheimer’s is the most common type of AD, seen in more than 90% of cases. Patients develop symptoms later in life, after the age of 65. As we start living longer because of better nutrition, healthcare and hygiene, the number of people afflicted with AD will continue to increase.
Several genetic changes have recently been identified that are linked to either an increased or decreased risk of developing AD. The APOE gene is the biggest genetic risk factor linked to late-onset AD. There are three versions (or alleles) of this gene – APOE e2, APOE e3 and APOE e4. Each parent passes a copy of the APOE gene to their children, meaning an individual may carry two identical copies of the APOE gene (homozygous) or two different APOE alleles (heterozygous).
40-65% of AD patients have at least one copy of APOE e4, compared to 20-25% of the general population. There is a 3-fold increased risk of AD if one copy of APOE e4 is present, and 15-fold increased risk if two copies of APOE e4 are present. There are at least 20 other genes also linked to Alzheimer’s disease, but none of these genes increase the risk of AD by the same magnitude as APOE e4.
Science has made it possible to know in advance whether or not we are predisposed to AD. What will worry most people about developing AD is not going to be the memory loss or the loss of independence. It will be the burden on loved ones. If you are a believer of the saying – better the devil you know than the devil you don’t – you might want to know your risk.
If you have the e4 version of APOE and know that your chance of developing AD is higher, would you be prepared to make changes now? Like to follow the six pillars of brain-healthy lifestyle – to eat right, exercise, sleep more, use your brain, manage stress and have an active social life. Most of us today would probably welcome the time to plan ahead, to help ease the burden, and to make the tough decisions involving our care while we could.
There is no cure for AD. However, we now understand the disease better, have a list of preventative methods, and know how to better manage AD. Scientists are making breakthroughs every day, from developing blood tests and advanced imaging techniques for early detection, to looking for drugs that might block the formation of plaques and tangles. Several clinical trials are underway for drugs that had promising preliminary results. Scientists around the world are confident that we may soon beat AD so we should remain hopeful.