|
E-mail this page to a friend!
Senior Citizen Health & Medicine
Genetic Variation May Be Factor in Half of
Age-Related Macular Degeneration
AMD is the most important cause of irreversible
visual loss in the elderly
July 19, 2006 Age-related macular degeneration
(AMD) is high on the radar of senior citizens concerned about their
vision. It is the most common cause of vision loss in the elderly.
Researchers now say that up to 50 percent of AMD cases may be caused by
a certain genetic variation, which along with inflammatory factors and
smoking, significantly increases the risk.
| |
Related Stories |
|
| |
Vision Loss Risk Factors for Senior Citizens: fish
good, tobacco bad, hormone therapy neutral
Three articles in
JAMA look at Age-Related Macular Degeneration Risks
July 10, 2006 - Eating fish frequently may be
associated with decreased chances of developing age-related macular
degeneration, while smoking nearly doubles the risk for this common
cause of vision loss and hormone therapy appears to have no effect.
Read
more...
FDA Approves Lucentis for Treatment of Wet
Age-Related Macular Degeneration
Monthly dose can maintain the vision of more than
90% of patients
July 2, 2006 - The Food and Drug Administration has
approved Lucentis (ranibizumab injection) for the treatment of patients
with neovascular (wet) age-related macular degeneration (AMD), the
leading cause of blindness in senior citizens. Lucentis is the first
treatment which, when dosed monthly by injection, can maintain the vision of more
than 90 percent of patients with this type of AMD.
Read more...
Discovery Could Lead to Treatment of Age-Related
Macular Degeneration
Bone Marrow may restore
eye cell damage that
causes AMD
June 9, 2006 - University of Florida scientists
conducting experiments with mice have found evidence that the body
naturally replenishes small amounts of cells in the eye essential for
healthy vision.
Read more...
New Finding Links Diet and Age-Related Macular
Degeneration
April 27, 2006 - Scientists funded by the
Agricultural Research Service (ARS)
reported this month that consuming a "high glycemic-index" diet over a
long period of time is associated with a higher risk of developing the
early stages of a major eye disease - AMD.
Read more...
Read more
on
Health & Medicine |
|
Age-related macular degeneration (AMD) is the most
important cause of irreversible visual loss in the elderly of the
Western world, according to background information in the article in the
July 19 issue of JAMA the Journal of the American Medical Association.
It has long been recognized that hereditary factors
play a role in AMD and there is increasing evidence that inflammation is
an important disease mechanism. Recent case-control studies demonstrated
an association between the complement factor H (CFH) gene, a regulator
of the complement pathway, and AMD.
Dominiek D. G. Despriet, M.D., of the Erasmus
Medical Center, Rotterdam, the Netherlands, and colleagues hypothesized
that the effect of this regulator gene may be particularly hazardous in
persons in whom the complement cascade is activated. They assessed the
association between the CFH gene and AMD and investigated the modifying
effect of smoking, serum inflammatory markers, and genetic variation of
C-reactive protein (CRP).
The population-based study included 5,681
individuals age 55 years or older who were assessed for the gene
mutation CFH Y402H. Information on smoking, serum inflammatory markers
and CRP gene variation were assessed at baseline.
The frequency of CFH Y402H was 36.2 percent. At
baseline, there were 2,062 persons (36.3 percent) with any type of AMD
(prevalent cases), including 78 (1.4 percent) with late AMD. During an
average follow-up of 8 years, 1,649 (35.5 percent) of 4,642 participants
progressed to a higher stage of AMD (new cases), including 93 (5.6
percent) who developed late AMD.
The researchers found that the CFH gene was a major
risk factor for AMD in the general population. The gene was implicated
in all stages of AMD from early hallmarks such as drusen (material that
builds up in the retina of the eye) to vision-disabling late AMD.
The risks increased with each successive AMD stage,
and homozygous individuals (i.e., with two identical gene copies of the
CFH Y402H mutation at the corresponding site on a chromosome), had an 11
times higher risk to develop late AMD compared to noncarriers.
Homozygous persons had a 48 percent cumulative risk of developing late
AMD by age 95 years while this risk did not exceed 22 percent for
noncarriers.
Factors that are known to activate the complement
cascade modified the association between CFH and AMD: smoking further
increased the risk of late AMD 34-fold; elevated serum CRP levels
increased the risk 28-fold; and elevated sedimentation rates increased
the risk 20-fold. The researchers also found a positive interaction
between the CFH and the CRP gene for AMD, in particular with those forms
of the gene predisposing for high serum CRP levels.
These data suggest that CFH Y402H may be a causal
factor in more than 50 percent of all AMD cases in the general
population.
Genetic predisposition to a malfunctioning CFH can
only be of importance when the complement system is switched on, the
authors write. This is demonstrated by the significant interaction
between chronic as well as acute inflammation and CFH Y402H.
The effect of CFH is significantly influenced by
environmental and genetic factors that determine the inflammatory
response and activate the complement pathway.
Click to More Senior News on the
Front Page
Copyright: SeniorJournal.com |
