Navigation Links
Toward a faster prenatal test for Down syndrome
Date:9/18/2007

Scientists in California are reporting an advance toward rapid testing for pre-natal detection of Down syndrome and other birth defects that involve an abnormal number of chromosomes.

In a study scheduled for the Oct. 1, 2007 issue of ACS journal, Analytical Chemistry, Stanford University bioengineering professor and Howard Hughes Medical Institute researcher Stephen R. Quake and his graduate student H. Christina Fan point out that most existing pre-natal tests depend on a technique termed karyotyping. It requires a two-week wait for anxious parents, while cells taken with amniocentesis or chorionic villus sampling are grown in laboratory culture and analyzed.

Laboratory studies with the new method produced accurate results within two hours. The test is a variation of the famed polymerase chain reaction (PCR) the basis of the genetic engineering revolution which produces thousands of identical copies of minute samples of DNA.

Using a technique known as the digital polymerase chain reaction, Quake and Fan replicated DNA from two cultures of cells growing in the laboratory. One consisted of a normal human cell line and the other had human cells with the Down variant. The digital PCR process allowed the researchers to count DNA molecules from the samples, substituting for the two-week cell culture process traditionally needed to produce enough DNA for karyotyping. With the precision derived from counting individual DNA molecules, researchers then were able to move ahead without delay and determine which samples had the extra chromosome that indicates Down syndrome.

The digital PCR was performed in a commercially available microfluidic chip. The samples were loaded onto the chip, and then partitioned into thousands of chambers by microscopic mechanical valves. While PCR was performed, fluorescent material in the compartments containing individual DNA molecules lit up like an array of LEDs, while those without DNA did not glow. The technique enabled researchers to confirm the presence of abnormal chromosomes typical of Down syndrome with great accuracy.

Rapid testing alternatives already exist, but they are either too labor-intensive or not applicable to the whole population. The technique we present in this paper can overcome these limitations. It is rapid and simple. We estimate that the entire procedure from sample collection to result readout would take only a few hours, substantially reducing the anxiety of the expectant parents, Quake said.

The test is also potentially cheaper than other available methods and semi-automated, reducing the workload of lab personnel. And since the digital PCR technique is based on commercially available lab equipment, any interested physician could use it.

We are confident that it will work on clinical samples of amniotic fluid or chorionic villus, Fran said. The next step is to begin clinical trials to evaluate the sensitivity and specificity of the new test. The authors believe the new test could be available in as little as one year.

In addition, Quake cited the possibility that the method could lead to a blood test for Down syndrome. It would involve capturing fetal cells, which leak through the placenta and circulate in the mothers blood, and analyzing their DNA for abnormalities with digital PCR. Other research groups are also investigating a digital PCR-based Down syndrome test, he noted.

As a non-invasive test, it would be the safest approach to prenatal diagnosis of Down syndrome, since both amniocentesis and chorionic villus sampling pose risks to the fetus. Quake noted, however, that new techniques to separate the small fraction of fetal DNA in a mothers bloodstream must be developed before a blood test could be developed and tested.


'/>"/>

Contact: Michael Bernstein
m_bernstein@acs.org
202-872-4400
American Chemical Society
Source:Eurekalert

Related medicine news :

1. Unravelling the secrets of ‘Huntingtin’ Protein - towards the treatment of ‘Huntingtons’ Disase
2. Unravelling the secrets of ‘Huntingtin’ Protein - towards the treatment of Huntingtins’ Disese
3. Looking Towards More Effective Leukemia Treatment
4. Attitude Towards AIDS Patients – Time For A Change
5. Scientists Awarded Appropriately For Contribution Towards Medical Research
6. Rural India shows apathy towards dental problems: Survey
7. Time magazine has recognized efforts of two Indian doctors towards reducing infant mortality rate
8. Doctors take part in walk: a step towards creating diabetes awareness
9. A Step Towards Unraveling The Schizophrenia And Depression Mystery
10. Are Women Not Hearty Enough Towards Seeking Heart Care?
11. Australia to Show Leniency towards U.S. Pharmaceutical Companies
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:7/21/2017)... ... July 21, 2017 , ... Fresh Wave® IAQ today announced the ... solution for colleges and universities at the APPA 2017 Annual Conference and ... and tobacco smoke odors without the use of harsh chemicals, Fresh Wave IAQ Smoke ...
(Date:7/21/2017)... ... ... Hawkins, Pastor and Overseer at The House of Yahweh in Abilene, Texas, has written a ... and pleads with world leaders to be more open about positive changes. Yisrayl says the ... there is a peaceful and positive way to solve all; yes, all issues, and he ...
(Date:7/21/2017)... (PRWEB) , ... July 21, 2017 , ... West Dermatology ... Tuantu Doan Vu, PA-C. Beginning July 17, 2017, Ms. Vu will join West Dermatology’s ... years of experience in dermatology, skin cancer , and more. She graduated from ...
(Date:7/20/2017)... Va. (PRWEB) , ... July 20, 2017 , ... ... McCarter, MD, has joined JenCare Senior Medical Center as Richmond Chief Medical ... Virginia School of Medicine, and Associate Chief Medical Officer of Ambulatory Services for the ...
(Date:7/20/2017)... , ... July 20, 2017 , ... ... telemedicine platform, in which their iMedSecure™ comes included with each system installation. ... live images to remote participants for real-time collaboration and immediate decision-making requirements. ...
Breaking Medicine News(10 mins):
(Date:7/21/2017)... -- Endo International plc (NASDAQ: ENDP ) today ... manufacturing network, the Company will be ceasing operations and ... Huntsville, Alabama . The closure of the facilities ... to 18 months. The Huntsville ... products and these restructuring actions are intended to better ...
(Date:7/20/2017)... -- Prime Therapeutics LLC (Prime) released this statement from its Chief ... for Clinical and Economic Review,s (ICER) public meeting ... of abuse-deterrent formulations (ADF) of opioids. Prime was the sole ... "The ICER data ... use of abuse-deterrent formulations (ADF) in opioids in terms of ...
(Date:7/17/2017)... , July 17, 2017  MedX Holdings, Inc., ... medical testing, strengthening and rehabilitation equipment, today announced the ... Program. MedX is considered the gold standard for the ... in specialized medical strengthening equipment. ... lease with the physician or practice who prescribe the ...
Breaking Medicine Technology: