tagged w/ Genetic Testing
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A gene mapping test could tell parents-to-be if embryos are affected by almost any inherited disease, UK scientists have claimed.
The team from London's Bridge Centre say the £1,500 test could detect any of the 15,000 inherited diseases in weeks.
Current tests are either focused on a specific gene mutation, or take a lot longer to give results.
But other experts warned the fertility regulator would have to ensure there were strict limits on the test's use.
At the moment, clinics can test embryos before they are implanted in a woman's womb to see if they carry a specific genetic mutation, if a family is affected by a condition such as cystic fibrosis.
Another test was developed by a team at Guy's Hospital in London two years ago, which looks at genetic "fingerprint" by looking at a whole DNA of a cell.
But the claims for this new technique, called karyomapping which analyses chromosomes, is that it is a universal 'one size fits all' test.
Mapping patterns
A single-cell is taken from an eight-day-old embryo, created using IVF.
DNA samples are then taken from the parents - and their parents.
Usually, another member of the family, most likely a child affected by the relevant condition, also provides a sample.
All those family members' DNA is then compared, looking at 300,000 specific DNA markers, allowing scientists create a map of the family's genetics.
This means they can, for example, identify if there is a block of DNA which has been passed on by the paternal grandfather to an affected child and if it is also present in the embryo - because the markers will be the same for all three.
For example, the gene for cystic fibrosis lies on chromosome 7. If the paternal grandfather was a carrier, and the embryo has inherited a section of DNA at that particular position, the embryo will have the faulty gene.
The same check can be carried out across all chromosomes to allow screening for multiple genes.
'Preventing suffering'
Professor Alan Handyside, who has developed the test, told the BBC: "The current tests can only identify a small number of defects."
"One of the main things for patients is that, quite often, there isn't a test for their particular condition. This is a single test - a universal method."
He said the test could also be used, more controversially, to detect a genetic profile which showed a susceptibility to conditions such as heart disease or cancer.
The test is currently being trialled at the Bridge Centre, but is being used alongside conventional pre-implantation genetic testing so doctors can check the results.
Once Professor Handyside has enough data he will need to apply to the fertility regulator, the Human Fertility and Embryology Authority, for a licence to use the test.
An HFEA spokeswoman said its licensing committee would be able to set conditions on what it could be used for.
Dr Mark Hamilton, chairman of the British Fertility Society, said: "The effectiveness and efficiency of the procedure is quite exciting, and the fact it's quicker means it could be helpful to couples at risk of inherited diseases - and that in itself is significant.
"We can currently test for several hundred conditions, but the claim is that the spectrum of conditions which could be screened for is enormous
"But obviously, the ethical question is, if you can screen for anything, where do you draw the line?" A gene mapping test could tell parents-to-be if embryos are affected by almost any... more
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A safer method to diagnose Down syndrome and other genetic disorders may one day become available using a genetic test performed on blood taken from pregnant women, researchers said.
Scientists from Stanford University and the Howard Hughes Medical Institute used a gene-sequencing method that amplified fragments of DNA found in the mother's blood, including a tiny proportion that comes from the fetus. The novel approach allowed them to detect excess genetic material from a specific chromosome, indicating a problem.
Such a blood test could be easier and less risky than other prenatal tests doctors now use to look for Down syndrome and other chromosomal disorders. The other tests include amniocentesis, which uses amniotic fluid extracted from the uterus and can cause complications including infection and miscarriage.
``We look for chromosomes that are overrepresented,'' said Stephen Quake, professor of bioengineering and applied physics at Stanford and the Howard Hughes Medical Institute. ``The breakthrough is we're able to measure very slight differences very accurately.''
Using the blood test, researchers accurately diagnosed nine cases of Down syndrome, two cases of another genetic disorder, trisomy 18, and one case of trisomy 13, all among 18 pregnant women. Trisomy means there are three copies of a chromosome in each body cell instead of the usual two. The results appeared yesterday in the online edition of the Proceedings of the National Academy of Sciences.
Women Tested
The study included blood drawn from 18 women at the Prenatal Diagnostic Center at Lucile Packard Children's Hospital and one man for comparison. The blood was taken when the women were 10 to 35 weeks pregnant and after a standard test such as amniocentesis was performed. More research is needed to confirm the findings and test the method's accuracy and reliability.
Down syndrome is the most common type of genetic birth disorder, affecting one of every 733 babies born in the U.S., according to the National Down Syndrome Society. It results when a person has three copies of the 21st chromosome and may cause low muscle tone, small stature, an upward slant to the eyes and developmental delays. Edward syndrome, or trisomy 18, and Patau syndrome, or trisomy 13, are less common, involve many complications and are often fatal. A safer method to diagnose Down syndrome and other genetic disorders may one day... more
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Should parents be required to have their babies undergo genetic testing?
The governor of Pennsylvania just signed a new law mandating newborn screening for six genetic and metabolic conditions. "Pennsylvania now joins many other states that screen for at least 29 conditions at birth."
Is this a sign of progress, or has government stepped too far?
Should parents be required to have their babies undergo genetic testing?
The... more
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A genetic testing company has stopped direct-to-consumer sales in California as a result of receiving a cease-and-desist letter from the state's health department.
HairDX, which offers a genetic test that claims to predict clients' risk of hair loss, has decided, on advice of legal counsel, to require California (and New York) residents to order their tests through a doctor.
Other companies targeted by California continue to sell their services in the state, but HairDX's CEO, Andy Gores, said closing down their Internet orders in the market was an easy decision.
"It's not our mainstay business," Gores said. "We are focused mainly on [selling through] doctors."
Still, the company's decision to stop offering its genetic test to California residents is a sign that the Public Health Department's cease-and-desist letters are already having an impact on the nascent genetic testing industry.
On June 9th, the Laboratory Field Services division sent the letters to thirteen genetic testing companies. So far, in addition to HairDX, only Navigenics, 23andMe and DNATraits have confirmed they received a letter.
The Health Department requested responses to the letters by today, June 23, containing plans for coming into compliance with the department's interpretation of California state clinical laboratory testing laws.
Gores, like representatives from other genetic testing companies Wired.com has spoken with, voiced frustration with the health department's one-letter-fits-all regulatory action.
"I think their letter is a shotgun approach," he said. "The 23andMes of the world are more in the entertainment realm... We're on the opposite end of the spectrum."
The company's attorney, Elliott J. Stein, said he was preparing a response for the state, but was unsure of exactly what type of compliance plan the state desired.
"I don't know how all of this is supposed to play out," he said, but was confident that his client's business would ultimately prove acceptable to the health department.
In the meantime, Laboratory Field Services' chief Karen Nickel's declaration that California is "no longer tolerating direct to consumer genetic testing," has already succeeded in pushing one company out of the state. A genetic testing company has stopped direct-to-consumer sales in California as a... more
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Genetic Information Nondiscrimination Act (GINA) of 2008 is expected to be signed into law by President Bush soon.
GINA will amend laws to prohibit a group health plan from adjusting premium or contribution amounts for a group on the basis of genetic information.
Reluctance to get genetic tests range from being fired, priced out of health insurance or dropped from coverage altogether.
Having been used to diagnose fetal problems for inherited diseases, the scope of testing has expanded in the last decade.
There are now about 1,500 genetic tests.
Washington’s Public Citizen group stated that some people have been misled by inaccurate results, and industry oversight is scant and superficial. As the new law takes effect, testing of the genetic tests also needs to be a priority.
My question: How will Big Brother safeguard the DNA tests?
Genetic Information Nondiscrimination Act (GINA) of 2008 is expected to be signed into... more
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