Limbic-predominant age-related TDP-43 encephalopathy (or
LATE-NC) is the most recently identified form of dementia, noted for its close
similarity to Alzheimer’s.
Overview
According to a study published in Brain, a Journal of
Neurology, on April 30, 2019, researchers have
linked a protein called TDP-43 to a newly identified form
of dementia: Limbic-predominant age-related
TDP-43 encephalopathy (LATE-NC).
Risks Factors
LATE usually affects older individuals, particularly
those over age 80. Although advancing age is a risk factor for LATE,
dementia is not part of the typical aging process.
Genetics can also increase a person's risk of
developing LATE. At least five genes are associated with the risk
of LATE. These same genes may also increase the likelihood of other forms
of dementia.
Symptoms
When TDP-43 accumulates in an area located in the
mid-brain known as the limbic system, it affects learning, memory and emotion,
resembling symptoms of Alzheimer’s disease, the most common form of dementia.
This suggests that people may exhibit symptoms mirroring
those of Alzheimer’s but it may not involve the same changes to the brain
caused by the disease.
People with LATE have problems with memory but
often have a slower rate of clinical change than people with Alzheimer's
disease. They may notice that over time it's more difficult to remember facts,
conversations and events. People with LATE may repeat themselves
often, be forgetful and have trouble finding the right words during
conversations. They may also have difficulty understanding words.
Individuals with LATE may:
·
Wander or get lost
·
Make poor decisions
·
Misplace things
·
Have trouble driving
·
Have difficulty keeping up with personal hygiene
Eventually, someone with LATE has trouble with
daily living activities such as dressing, cooking or paying bills. The mental
decline in LATE is slower than in other forms of dementia. This
causes a slow, rather than a rapid, worsening of symptoms.
Diagnosis
Currently, LATE-NC is not diagnosable with standard
tests. Because people are typically diagnosed with
certain types of dementia based on the symptoms they
experience, LATE-NC will not be easily
distinguished from Alzheimer’s due to overlapping
symptoms.
LATE usually affects older individuals, particularly
those over age 80. Although advancing age is a risk factor for LATE,
dementia is not part of the typical aging process.
Genetics can also increase a person's risk of
developing LATE. At least five genes are associated with the risk
of LATE. These same genes may also increase the likelihood of other forms
of dementia.
Currently, LATE can only be definitively
diagnosed after death through an autopsy. But for people with symptoms, a
diagnosis of LATE can be suggested through:
·
Clinical history
·
MRI or fluorodeoxyglucose (FDG)-positron
emission tomography (PET) findings
·
Ruling out other causes
Your health care provider may look for changes in the
brain that can be caused by LATE. These can include signs of brain
shrinkage (atrophy) and thinning of the parts of the brain responsible for
memory formation. These changes can be seen on MRI examination and on
autopsies. Thinning seems to be a stronger indicator of how severe the disease
is compared with atrophy.
A buildup of the protein transactive response DNA-binding
protein 43(TDP-43) may be another sign of LATE. This naturally occurring
protein helps with nerve development. This buildup of TDP-43 is
usually found in the part of the brain that supports memory, emotion, behavior
and mood (limbic system). Right now, there isn't a simple test to see whether a
person has an excessive amount of TDP-43. This would be discovered only
with an autopsy.
Another sign that could suggest a diagnosis
of LATE is hardening and thickening of the walls of the arteries
(arteriolosclerosis), which is common in people with LATE.
If your health care provider suspects you might
have LATE, they may suggest a mental status examination to find out how
severe the cognitive impairment is.
Researchers are working to find a simpler way to
diagnose LATE, and other forms of dementia, to quickly identify these
diseases. Researchers are working to develop a simple blood screening test for
dementia, including LATE, but that is still being studied.
Treatment
As LATE-NC was only just recently discovered, there is no
available treatment at this time.
To help improve overall health and manage the symptoms of
dementia, the World Health Organization (WHO) has made recommendations that
include:
·
Increasing physical activity
·
Maintaining a healthy diet
·
Decreasing alcoholic intake
·
Avoiding smoking
·
Treating chronic conditions such as
hypertension, high cholesterol, depression, obesity and diabetes
Sources and additional information:
https://alzheimer.ca/en/about-dementia/other-types-dementia/late-nc
