Early-onset Alzheimer's Disease - Facts - Information
Early-onset Alzheimer’s is a very rare form of the disease affecting less than 10% of all those diagnosed with Alzheimer’s. It encompasses everyone with the disease under the age of 65.
Tragically it includes people as young as 35 and many people suffering from early-onset Alzheimer’s are in their 40s and 50s.
Younger people who develop Alzheimer’s have very similar symptoms to those in the older age group but very often, because of their age, they are still active, possibly at work and with younger children.
Memory loss, confusion, personality changes and difficulties performing simple tasks are all very common. Eventually emotional and social withdrawal will become the norm.
A condition called myoclonus which causes muscle twitching and spasms is much more common in people with early onset than those who develop the disease later in life.
All these factors combine to make it very difficult for someone in the younger age group to continue to work or even take part in normal family life. Their illness might not be diagnosed for a while because of their age and their baffling symptoms could be put down to a lack of motivation or depression.
Theories Behind Early Onset AD
There is some suggestion that people with early-onset Alzheimer’s have a more rapid decline than those who are older. Whether this is really the case is the subject of much debate.
Some researchers believe that because a person is affected at a young age that they react differently to the illness by becoming frustrated, depressed and even in some cases by giving up all together through fear of what the future holds. It could be this which causes them to decline quicker and not the actual process of the disease.
Certainly it is known that younger people with Alzheimer’s have more of the tiny tangles and plaques which tend to be seen in the brains of people with Alzheimer’s. It could be that young brains need more damage before they show any symptoms.
Early-onset Alzheimer’s is associated with the mutations of three genes – presenilin 1, presenilin 2 and amyloid precursor protein. In isolation these genes do not cause Alzheimer’s but scientists have found that if they mutate they can spark the disease.
In very few cases associated with early-onset Alzheimer’s (around 1%) there’s a clear genetic link running through certain families. These families usually inherit a genetic fault on specific chromosomes – in this case, chromosomes 21, 14 or 1. When this happens roughly 50% of the offspring of these sufferers will carry the genetic fault and in all cases they will go on to develop Alzheimer’s.
Early-onset Alzheimer’s is also seen in a high proportion of people with Down’s Syndrome who have an extra copy of chromosome 21 and age more prematurely than people without the condition. They develop the same plaques and tangles in their brains as others with Alzheimer’s and researchers believe that there is some direct link to the extra copy of chromosome 21 which is so important in the development of familial Alzheimer’s.