If Grandma has Alzheimer’s will I get it? The Genetics of Alzheimer’s.

Alzheimer’s disease affects millions of people across the country, including loved ones of those who suffer from the condition.  Imagine how it would feel to visit someone you love dearly and to them be unable to recognize who you are, just like you were a total stranger.  This is the case for many who have loved ones with Alzheimer’s.  Alzheimer’s is a progressive neurodegenerative disease that typically affects older individuals (65 and older); it is characterized by severe loss of memory and other cognitive functions that impairs daily life.  Recent research has discovered that the damage to neurons that lead to the onset of Alzheimer’s is caused by the buildup of a protein, creating plaques and protein tangles, in the space between two neurons which impairs communication and signaling of messages through neurons in the brain.
So, with the number of people that Alzheimer’s affects, should one be worried about “inheriting” the disease from a family member who suffers from the disease?  More often than not, Alzheimer’s is not a disease that is usually inherited from other family members because it usually occurs sporadically; which might actually be scarier because a seemingly healthy and mentally sharp person could still develop Alzheimer’s disease.  The number one risk factor of the disease is actually old age.  Now that is not to say that Alzheimer’s is never linked to genetics, actually about 5-10% of total cases in the United States of Alzheimer’s are attributed to the familial version of Alzheimer’s, which is inherited in an autosomal dominant fashion.  This means that if your mother or father suffered from the familial version of Alzheimer’s and then you receive this allele you will develop Alzheimer’s because regardless of the other allele you inherit the familial Alzheimer’s allele will show up.  Familial Alzheimer’s is associated, almost all of the time, to the early onset form of the disease (onset before 65, usually 40s or 50s).  Researches have located three genes that if mutated can lead to the development of Alzheimer’s.  All of these genes regulate a protein, Amyloid Precursor Protein (APP), that is found in the cell membrane of the neurons in your brain and mutations of these genes lead to incorrect cutting of APP, creating other smaller proteins such as amyloid-b (AB).  Due to these genes increasing the cutting of the protein APP the accumulation of AB outside of the neurons in the synaptic space becomes a problem because they start to aggregate and create plaques and protein tangles, which eventually will lead to impaired signaling and communication between neurons.  The impaired communication due to plaques and tangles is the reason why those affected have memory loss because the information for the memory is trying to be sent but because of these plaques blocking the way the signal is never received to be remembered.  And if these neurons are unable to receive signals and other nutrients they end up dying which also accounts for the loss of memory as well as other cognitive functions.  Don’t worry too much about the familial form of Alzheimer’s because it is very rare and there is genetic testing that can be done to assess your risk and you can take appropriate steps to delay the onset of the disease, because sadly there is no cure to this disease.
 
For more information of Alzheimer’s visit the official Alzheimer’s organization site at http://www.alz.org/