Those with two copies of the commonest form of the gene (one copy inherited from each parent) smoked most.
The idea of treating disease by replacing a defective gene with a working copy gained credence in 1990 with the success of the world's first gene therapy clinical tests against a rare condition called severe combined immunodeficiency (SCID).
In this case the blistering happens even if the other copy of the gene is healthy.
Women have two X chromosomes, and a normal copy of the gene will override the defective one.
In most cases in this study, a bad copy of a gene from a parent was not to blame.
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The therapy, developed by UniQure, uses a virus to infect muscle cells with a working copy of the gene.
To keep things straightforward, the researchers chose to work with mice who carried just one copy of the gene.
Excited, Chalfie called Prasher and asked for a copy of the gene.
This is probably because the gene helps when only one copy is present, but hinders when there are two, one from each parent.
We counted the number of times we saw a copy of a gene in normal tissue and then in the diseased one, says David Searls, SmithKlines director of bioinformatics.
These carrier screenings involve identifying individuals who carry one copy of a gene for a disease that requires two copies for the disease to be expressed in a child.
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But if an effect is there, it will always be there unless it is masked by a second, undamaged copy of the gene in question. (There are two versions of most genes in an individual, one inherited from each parent.) That, at least, is the received wisdom.
However, by adding a healthy copy of the BRCA1 gene they were able to restore the surveillance system.
If it is safe, the medicine could also be used for patients who have a single copy of the defective gene.
Those who have a single copy of the bad gene still suffer from very elevated cholesterol and a high risk of heart attack, and might also use 301012.
Such variability could be due to environmental factors, but Dr Gibson suspected it might actually be due to minor variations in the healthy copy of the Egfr gene.
The Web report said I had inherited one copy of the diabetes gene (four out of ten people have it), elevating my risk a mere 20% over those without the gene.
Some 600, 000 Americans have the more common form of FH, which is caused by a single bad copy of the cholesterol gene and causes levels of cholesterol that are just above the upper limit of normal.
Zeneca ordered a "wet" copy of a promising gene, in the form of a clone -- a colony of bacterial cells whose members all carry the desired snippet of DNA. These bacterial guinea pigs can then be used to try out antibacterial chemicals.
The surprise was that although men with a copy of the apo E-4 gene made up less than 16% of the group, they accounted for 26% of the heart-disease deaths.
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Among families with parkin mutations, 13 had at least one member with mutations on both copies of the gene, while in 10 families affected members had a single mutated copy of parkin.
Some 600, 000 Americans have a less severe version caused by one defective copy. (There would be more of the double-gene victims if they didn't die young.) To get its drug approved Isis will need to study 45 patients with the severe two-gene form and a few hundred with the single-gene disease.
In a subgroup of families who had identical chromosome markers, those with no mutations in the gene developed symptoms at an average age of about 61, those with a single abnormal copy of parkin at around age 50, and those who inherited two mutated copies had onset at around age 36.
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