http://www.eurekalert.org/pub_releases/2008-06/muhc-sdd061908.php
Same drug, different results: MUHC researcher on the path to
personalized medicine
Minor genetic differences between individuals change the effect of a
common medication, study shows
This release is available in French.
Montreal, June 18, 2008 =96 Medicine has moved a little bit closer to
the era of tailor-made treatments, based on the unique genetic
profiles of individual patients, according to recent research
conducted by Dr Rima Rozen of the Research Institute of the McGill
University Health Centre (RI MUHC) at the Montreal Children's Hospital
and McGill University. Her study, published June 18 in the journal
Pharmacogenetics and Genomics, shows how minor genetic differences
between individuals alter the way a common drug affects the body.
Rozen has measured the impact of Methotrexate -- a drug that inhibits
the metabolism of folate -- on mice with an altered MTHFR gene, which
is a gene crucial for folate metabolism. The results were striking:
after treatment with Methotrexate, mice with the altered gene had
approximately 20 per cent less hemoglobin and red blood cells than
their counterparts with non-altered genes. The altered mice also
showed increased susceptibility to liver and kidney damage following
treatment.
"We know that these results are applicable to humans because a
parallel mutation in the human MTHFR gene affects human folate
metabolism similarly. The results demonstrate that medication affects
subjects differently according to individual genetic traits," Dr.
Rozen explained. "And tests exist to detect this mutation." Genetic
testing would allow physicians the modify treatment based on each
patient's personal genetic makeup, limiting potential side effects.
In earlier studies, Rozen's laboratory cloned the MTHFR gene and
identified the common variant which interferes in folate metabolism in
human populations. Between 10 and 15 per cent of the total caucasian
population have two copies of the variant in MTHFR. Folate, a form of
water-soluble Vitamin B2, is essential to the production of red blood
cells and provides protection against spina bifida, other birth
defects, and heart disease. Patients with cancer or auto-immune
diseases are often treated with medications that affect folate
metabolism, but physicians are not trained to verify how patients
naturally metabolize folate, even though this could be an im****tant
factor in effective treatment.
"This is a first step towards personalized medicine that is based not
only on symptoms but also on the patient's own genetic 'baggage,'"
Rozen said. "This trend definitely represents the medicine of the
future."
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Luke
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