Iron-storing disorders shed light on Parkinson's
July 24, 2001
NEW YORK (Reuters Health) - Researchers have uncovered
genetic
defects underlying two rare disorders in which iron
builds up in brain
cells, resulting in deteriorating brain function.
The findings may help researchers understand more
common
disorders, such as Parkinson's, Huntington's and
Alzheimer's disease,
which also involve increased levels of iron in brain
cells, researchers
say.
The two studies were reported July 23 in an online
publication of Nature
Genetics. In the first study, Dr. John Burn from the
Institute of Human
Genetics, Newcastle upon Tyne, UK, and his colleagues
identified a
genetic mutation that resulted in patients having
symptoms similar to
those of people with Huntington's or Parkinson's
disease.
The symptoms of the disorder, called adult-onset basal
ganglia
disease, include involuntary movements, spasticity and
rigidity, and
typically strike patients between 40 to 55 years of
age. However, the
patients do not show a decline in reasoning ability.
Burn's team examined genetic material from five
patients with the
disorder and compared it with that of three healthy
people. The
investigators found that all of the affected
individuals had a defective
version of an iron-storing protein, which could cause
iron to accumulate
in brain cells.
In the second paper, Dr. Susan J. Hayflick from the
Oregon Health and
Science University in Portland, and colleagues
describe their discovery
of the genetic defect underlying a rare disorder
called
Hallervorden-Spatz syndrome (HSS). These patients,
numbering about
100 in the US, also suffer severe damaging effects
from a buildup of
iron in their brain cells.
"People with Parkinson's disease have increases of
iron in their brain in
some of the same areas in which it is increased in
HSS," Hayflick told
Reuters Health. "We are speculating that some
variation in this gene
(that causes HSS) may be at the basis of the common
forms of
Parkinson's disease," she said.
"We are actually looking now at a group of Parkinson's
patients to see
if there are changes in this gene," Hayflick said. "We
don't think this
gene is going to be the cause of all Parkinson's
disease, but it may be
a significant contributor," she said.
According to Hayflick, the iron buildup is caused by a
mutated protein
that is unable to break down a B vitamin called
pantothenic acid, or
vitamin B5. This defect, through a chain of events,
may trigger the
accumulation of iron, she said.
Hayflick did not want to speculate on whether taking
pantothenic acid
as a vitamin supplement may help or hinder HSS or
Parkinson's, but
she said, "we are working to develop compounds (based
on
pantothenic acid) that would be able to get into cells
in order to treat
the disorder(s)."
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