Early Detection of Alzheimer's Disease: Mutations of Three Genes Studied
Posted Jul 21 2011 12:00am
From a diagnostic perspective, one of the hottest current issues is the early detection of Alzheimer's disease. The volume of testing for Alzheimer's will undoubtedly be large so that the commercial market for a lab test will be attractive (see: Diagnosing Alzheimer's Disease with Imaging and Biomarkers ). Also, obtaining a population of patients with documented early disease is critical in the development of clinical trials for early drug treatment. Below is an excerpt from an article about early testing for three gene mutations (see: Clinical trials to detect Alzheimer’s 20 years before dementia onset planned ):
Inherited forms of Alzheimer’s disease may be detectable as many as 20 years before problems with memory and thinking develop....Identifying Alzheimer’s in its earliest stages is a top priority for researchers. Many think that by the time symptoms become apparent, Alzheimer’s disease has already damaged the brain extensively, making it difficult or impossible to restore memory and other mental abilities....Initial...results [from an international study network] confirm and expand upon earlier insights from studies of the more common sporadic forms of Alzheimer’s, including data suggesting that changes in the levels of biological markers in the spinal fluid can be detected years before dementia....[R]esearchers are studying members of families who have mutations in one of three genes: amyloid precursor protein, presenilin 1 or presenilin 2. Participants with these mutations are certain to develop Alzheimer’s disease early, with symptoms beginning in their 50s, 40s, or, in some rare cases, 30s....By looking at the age of symptom onset in a parent who passed an Alzheimer’s mutation to a...participant [in the study network], scientists can establish an estimated age of onset for a study participant. If a parent developed dementia at the age of 50, they would expect a child who inherited the mutation to develop dementia at roughly the same age. As a result, scientists can start amassing a detailed chronology of disease progression that covers the many years Alzheimer’s is active in the brain but still before the onset of dementia....Washington University researchers....will report initial results from [the study network], including confirmation of the value of disease indicators from cerebrospinal fluid analyses. Participants who carry the mutations but are still asymptomatic have significantly lower levels of amyloid beta and higher levels of tau protein in their cerebrospinal fluid than participants without the mutations.
I think that most patients will readily agree to undergo biomarker testing to detect early stages of cancer. This is because early detection of most types of the disease can effect a cure or amelioration of it. However, I suspect that some, or even most, patients might not be as eager to undergo testing to diagnose early stage Alzheimer's. This is a consequence of not having effective drug therapy for the disease at this time. There's a chicken-and-egg problem here -- we need the patients to run the clinical trials of various drug candidates to find a cure.
It also occurred to me as I was writing this note that I was focusing mainly on the lack of drug therapy for Alzheimer's, particularly in those genetically predisposed to developing it. It did not immediately occur to me that there were potentially other ways to forestall or prevent the disease such as changes in lifestyle (Exercise and a Mediterranean Diet Lower the Risk of Alzheimer's Disease ). This thought was reinforced when I discovered another article that suggested that exercise can stave off dementia in the elderly but this was primarily cognitive problems resulting from vascular disease (see: More, better evidence that exercise staves off dementia: two new studies ).
From a diagnostic perspective, one of the hottest current issues is the early detection of Alzheimer's disease. The volume of testing for Alzheimer's will undoubtedly be large so that the commercial market for a lab test will be attractive (see: Diagnosing Alzheimer's Disease with Imaging and Biomarkers ). Also, obtaining a population of patients with documented early disease is critical in the development of clinical trials for early drug treatment. Below is an excerpt from an article about early testing for three gene mutations (see: Clinical trials to detect Alzheimer’s 20 years before dementia onset planned ):
Inherited forms of Alzheimer’s disease may be detectable as many as 20 years before problems with memory and thinking develop....Identifying Alzheimer’s in its earliest stages is a top priority for researchers. Many think that by the time symptoms become apparent, Alzheimer’s disease has already damaged the brain extensively, making it difficult or impossible to restore memory and other mental abilities....Initial...results [from an international study network] confirm and expand upon earlier insights from studies of the more common sporadic forms of Alzheimer’s, including data suggesting that changes in the levels of biological markers in the spinal fluid can be detected years before dementia....[R]esearchers are studying members of families who have mutations in one of three genes: amyloid precursor protein, presenilin 1 or presenilin 2. Participants with these mutations are certain to develop Alzheimer’s disease early, with symptoms beginning in their 50s, 40s, or, in some rare cases, 30s....By looking at the age of symptom onset in a parent who passed an Alzheimer’s mutation to a...participant [in the study network], scientists can establish an estimated age of onset for a study participant. If a parent developed dementia at the age of 50, they would expect a child who inherited the mutation to develop dementia at roughly the same age. As a result, scientists can start amassing a detailed chronology of disease progression that covers the many years Alzheimer’s is active in the brain but still before the onset of dementia....Washington University researchers....will report initial results from [the study network], including confirmation of the value of disease indicators from cerebrospinal fluid analyses. Participants who carry the mutations but are still asymptomatic have significantly lower levels of amyloid beta and higher levels of tau protein in their cerebrospinal fluid than participants without the mutations.I think that most patients will readily agree to undergo biomarker testing to detect early stages of cancer. This is because early detection of most types of the disease can effect a cure or amelioration of it. However, I suspect that some, or even most, patients might not be as eager to undergo testing to diagnose early stage Alzheimer's. This is a consequence of not having effective drug therapy for the disease at this time. There's a chicken-and-egg problem here -- we need the patients to run the clinical trials of various drug candidates to find a cure.
It also occurred to me as I was writing this note that I was focusing mainly on the lack of drug therapy for Alzheimer's, particularly in those genetically predisposed to developing it. It did not immediately occur to me that there were potentially other ways to forestall or prevent the disease such as changes in lifestyle (Exercise and a Mediterranean Diet Lower the Risk of Alzheimer's Disease ). This thought was reinforced when I discovered another article that suggested that exercise can stave off dementia in the elderly but this was primarily cognitive problems resulting from vascular disease (see: More, better evidence that exercise staves off dementia: two new studies ).