Wednesday, May 12, 2010

Rapid Prenatal Test for Alpha-Thalassemia

Interesting article in Science Daily today on alpha-thalassemia screening. We will read the actual article and report on what assay methods they are using.

ScienceDaily (May 11, 2010) — Researchers from Mahidol University in Thailand have developed a rapid, high-throughput screening method for prevention and control of the blood disease thalassemia.

Their report appears in the May 2010 issue of The Journal of Molecular Diagnostics.

α-Thalassemia is a blood disease caused by a genetic defect in the production of a component of hemoglobin. This disease is more prevalent in areas that either were previously or are currently endemic for malaria, including the Mediterranean and South Asia. Carriers of mutations in α-thalassemia may have some degree of protection against malaria, but children of parents who both carry the mutation α-thalassemia-1 may develop Hb Bart's hydrops fetalis, which results in fetal death in utero or soon after birth.

Prenatal screening and genetic counseling are essential for prevention and control of α-thalassemia. The current diagnostic assay is both labor-intensive and time-consuming. Therefore, researchers led by Dr. Saovaros Svasti of Mahidol University developed a novel, rapid, and reliable assay for the diagnosis of α-thalassemias. This assay has high sensitivity and specificity, rapid turnaround time, and a decreased risk of contamination between samples.

Munkongdee et al suggest that this technique will "allow [for] high throughput screening suitable for prevention and control of thalassemia in the Southeast Asia population."

This study was supported in part by Vejdusit Foundation.
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Adapted from materials provided by American Journal of Pathology, via EurekAlert!, a service of AAAS.

Journal Reference:

1. Munkongdee T, Vattanaviboon P, Thummarati P, Sewamart P, Winichagoon P, Fucharoen S, Svasti S. Rapid diagnosis of α-thalassemia by melting curve analysis. Journal of Molecular Diagnostics, 2010; 12: 354-358 DOI: 10.2353/jmoldx.2010.090136

Sunday, May 9, 2010

Diseases that may be resulting from competition between the mother and the baby

A very interesting article in Science Daily today titled: "Gender Specific Disease Risks Start in the Womb":

Pregnancy places competing demands on a mother's physiology: Her body wants to produce a strong healthy baby but not at the expense of her own health. Some of the genes that she passes on to her child therefore try to protect her own body from excessive demands from her child. These so-called "imprinted genes" inherited from the father however do not show the same restraint -- their goal is to get as many resources for the fetus as possible.

Evidence that this battle of the imprinted genes might be at the root of later life disease processes will be presented at the International Conference The Power of Programming in Munich on 6 to 8 May, organized by the EC-funded Early Nutrition Programming Project (EARNEST).

"The imprinted genes derived from the father are greedy whilst those from the mother are conservative in their needs to ensure future reproductive success," said Dr. Miguel Constancia from the University of Cambridge, England. "We have found evidence that imprinted genes play important roles in the control of endocrine functions of the placenta. These placental adaptations have marked effects on nutrient delivery to the fetus, resulting in the programming of homeostatic mechanisms with metabolic consequences extending to adulthood, for example for type 2 diabetes susceptibility."

There is evidence that some programming effects are different in male and female offspring. Dr. Rachel Dakin from the University of Edinburgh, Scotland, shows how maternal obesity is associated with sex-specific programming effects in young adult mice. Female offspring of obese mothers had raised blood insulin levels, whilst male offspring did not. Male offspring did have alterations in the expression of liver genes important in lipid and glucocorticoid metabolism.

Professor Claudine Junien from the Institut National de Recherche Agronomique (INRA) in France says: "For me a gene, a cell and even a sex does not think and has no intelligent design. Instead it reacts to diverse environments and situations according to what its build-up can afford, pushing in one direction or another (or several at a time). The limits to which it can go without going awry or dying have been established progressively throughout the slow and long process of evolution, with different genetic backgrounds throughout the world depending on the diversity of experiences over the ages. We have data showing that gene expression and DNA methylation are sexually dimorphic in male and female placentae under normal/control conditions. Surprisingly, in stressful conditions, such as a high fat diet or low calorie diet, or maternal overweight/obesity -- the male and female placentae do not use the same strategies: they use different gene pathways and networks to cope with the stress. Does this directly lead to different outcomes? It may lead to sex-dependent differences in the outcome of programming with long lasting effects. Alternatively, it may be that metaphorically speaking males climb the mountain taking the north face while females take the south face -- but they ultimately reach the same peak after using these different paths."

Professor Ricardo Closa Monasterolo from the University Rovira I Virgili of Tarragona, Italy, presents work that suggested that infant boys and girls might have different responses to lower or higher protein diets. Females given higher protein formula milk had higher IGF-1 levels than males, whilst males showed higher C-peptide/creatinine levels compared to females. The significance of lower or higher protein diets has also been examined in the EU Childhood Obesity Project (CHOP) co-ordinated by Professor Berthold Koletzko of Ludwig-Maximilians-Universität (LMU) in Munich. Starting in 1990, over 1,000 infants were followed.

The first results show that, after 2 years, the infants fed a formula milk with a lower protein content -- closer to the composition of breast milk -- weighed significantly less than those on higher protein formula, with their weights being more similar to those of breast fed infants. These differences emerged by 6 months of age and persisted, even after the intervention ceased and the children went onto similar diets. The researchers predict that these low protein induced differences in early growth would reduce obesity at 14 to 16 years of age by 13%.

Koletzko, who is also the Co-ordinator of the EARNEST project said, "This is a new and exciting area of research which suggests that some of the differences in disease risk seen in men and women in later life might be explained by different responses to programming effects in early life."

Source: http://www.sciencedaily.com/releases/2010/05/100506205427.htm?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+sciencedaily+%28ScienceDaily%3A+Latest+Science+News%29&utm_content=Google+Feedfetcher

Happy Mother's Day!

On a note remotely related to sequencing and prenatal diagnostics, we would like to wish all of the mothers and soon-to-be mothers a very Happy Mother's Day!

Unfortunately, many countries disagree on the calendar date for this celebration, which goes goes back many centuries and can be traced to ancient Greece, and have conveniently correlated it with their respective religious holidays.

The following countries celebrate Mother's Day on the second Tuesday of May:


    * Australia
    * Austria
    * Bahamas
    * Barbados
    * Bangladesh
    * Belgium
    * Bermuda
    * Brazil
    * Canada
    * Chile
    * China
    * Colombia
    * Cuba
    * Croatia
    * Czech Republic
    * Denmark
    * Ecuador
    * Finland
    * Germany
    * Greece
    * Hong Kong
    * Iceland
    * Italy

    * India
    * Ireland
    * Jamaica
    * Japan
    * Latvia
    * Malta
    * Mexico
    * Netherlands
    * New Zealand
    * Peru
    * Philippines
    * Puerto Rico
    * Singapore
    * South Africa
    * Switzerland
    * Taiwan
    * Turkey
    * Uruguay
    * UK
    * USA
    * Zimbabwe








Thursday, May 6, 2010

SEQUENOM TO LAUNCH SEQUENCING-BASED TEST FOR DOWN SYNDROME (T21) SOON!

Big news today:

Sequenom (Nasdaq: SQNM) is planning to launch the Non-Invasive Down Syndrome test as an LDT (and likely FDA-regulated test) at the end of 2011. 
So the 35+ women will not need to stay on birth control for much longer! 

Let's hope that some socially-responsible investors will help finance the company soon so it starts working on more tests. 

 
Here is the press release from Sequenom.Com website: 

Sequenom Reports First Quarter 2010 Financial Results

-Company Unveils Trisomy21 Test Development & Launch Timeline-
-First Quarter Revenues Grow 22% Year-Over-Year to $10.6 Million-
SAN DIEGO, May 6, 2010 /PRNewswire via COMTEX/ --Sequenom, Inc. (Nasdaq: SQNM) today reported its financial results for the first quarter ended March 31, 2010.
(Logo: http://www.newscom.com/cgi-bin/prnh/20040415/SQNMLOGO)
First Quarter Results

  • Total revenue for the first quarter of 2010 grew 22% to $10.6 million, compared with $8.7 million for the first quarter of 2009. The increase in revenue was due to higher systems and consumables sales over the same period last year.
  • Net loss for the first quarter of 2010 was $16.9 million, or $0.27 per share, compared with $17.5 million, or $0.29 per share, for the first quarter of 2009.
  • Net cash used in operating activities was $13.4 million for the first quarter of 2010.
Gross margin in the first quarter of 2010 was 50.5% compared with 60.6% for the first quarter of 2009, reflecting increased costs associated with the start-up of the diagnostics business and changes in the mix of products sold in the genetic analysis business. The overall gross margin included a 61% margin generated by the genetic analysis segment which was offset by the negative margin generated from the company's molecular diagnostics segment.
Research and development (R&D) expenses were $11.2 million for the first quarter of 2010, compared with $8.8 million for the same period in the prior year. The increase was primarily related to clinical sample acquisition costs associated with the company's Trisomy 21 (T21) program and a licensing payment for certain intellectual property rights for age-related macular degeneration (AMD) related genetic variants.
Selling, general and administration expenses of $11.1 million for the first quarter of 2010 decreased from $14.3 million for the first quarter of 2009. The decrease was primarily due to decreased legal fees associated with litigation and lower share based compensation expense.
Total costs and expenses for the first quarter of 2010 were $27.5 million, compared with $26.5 million for the comparable quarter in 2009. For the three months ended March 31, 2010 and 2009, the company recorded $2.4 million and $3.0 million, respectively, of stock-based compensation expense.
Cash, Cash Equivalents and Available for Sale Securities
As of March 31, 2010 Sequenom had total cash and short- and long-term marketable securities of $29.2 million and $8.6 million in accounts receivable.
"The Sequenom team is optimistic about the future opportunities that lie ahead for our genetic analysis and molecular diagnostics businesses." stated Harry F. Hixson, Jr., Ph.D., chairman and chief executive officer. "We are pleased to announce timelines for the development and clinical testing of our T21 test, which we expect will be of interest to physicians, patients and investors. Successfully meeting our T21 test development milestones, advancing our AMD test development program, and seeking partnering opportunities for some of our unfunded projects will be a major focus for Sequenom during 2010."
Paul V. Maier, interim chief financial officer, stated, "Overall first quarter financial results met our expectations. Our achievement of more than $10 million of revenue in a quarter that historically has lower revenues is a good indicator that we can deliver growth in 2010. As a result, we believe that orders for the MassARRAY system and related consumables will provide a concrete foundation for the company as we continue to develop our molecular diagnostics capabilities."
Recent and Upcoming Business Highlights
T21 (Down syndrome) Update - The company remains committed to the development, validation and launch of a noninvasive T21 test. Following extensive scientific experimentation, the company has decided to proceed with a purely DNA based method for the detection of the T21 aneuploidy using massively parallel sequencing. Taken together the R&D and clinical sample collection costs required for a key T21 test validation study represent the single largest investment the company will make in 2010.
The company has established a number of program milestones to measure progress in the development of its noninvasive T21 test. Each milestone will be dependent upon the successful completion of preceding milestones:

  • The company anticipates optimization of a DNA sequencing-based test to be completed by the end of the third quarter of 2010.
  • By the end of 2010 our third party sample collection sites expect to have collected a sufficient number of blood samples from high risk pregnancies in order to provide the requisite number of T21 and euploid samples that will enable our planned blinded clinical studies. These blinded studies represent the pivotal validation studies to support launch of a noninvasive T21 test.
  • The company anticipates that Sequenom CMM, its CLIA laboratory, will start accessioning and testing these T21 and euploid samples during the fourth quarter of 2010.
  • To support the launch of a laboratory developed test (LDT) by the end of the fourth quarter of 2011, the company plans to complete testing of the validation samples during the second quarter of 2011.
  • Data analysis for the blinded validation studies, manuscript preparation, journal submission by our academic clinical partners and peer-review are expected to be completed by the end of 2011.
  • Following acceptance by a peer-reviewed journal the company plans to launch its T21 test as a LDT before the end of 2011.
  • The company plans to complete the appropriate studies and documentation necessary to file for a premarket approval (PMA) for the T21 test by the end of 2012.
Expanding Diagnostic Opportunities - In order to meet anticipated demand for the LDTs the company is developing, Sequenom plans to open a second CLIA-certified laboratory in its San Diego facility. It is anticipated that this lab will be operational early in the fourth quarter of 2010.
In February 2010 the company entered into a license agreement with Optherion, under which Sequenomwas granted an exclusive, worldwide, royalty-bearing license to know-how and a consolidated portfolio of issued and pending patent rights relating to age-related macular degeneration diagnostics. This portfolio had been assembled by Optherion from a number of prominent academic institutions. The licensed patent portfolio includes 17 issued or allowed United States and foreign patents, and 68 pending United States and foreign patent applications. The license agreement covers extensive intellectual property rights for significant AMD related genetic variants. The company expects to launch an AMD LDT during the first half of 2011.
Commercial Launch - On April 19, 2010, the company announced the availability of its next generation MassARRAY platform, the MassARRAY Analyzer 4. This new high performance nucleic acid analysis platform has been designed to meet customer demand for a bench top instrument with greater flexibility across multiple applications, improved reliability and faster performance. With the capability for quantitative gene expression analysis, epigenetic nucleic acid methylation analysis as well as high-throughput genotyping and SNP fine mapping applications, the MassARRAY Analyzer 4 is designed to empower the basic and translational research community to advance findings from basic genetic and biomarker studies toward clinical utility in diagnosis, prognosis and monitoring of diseases. The MassARRAY Analyzer 4 system will be initially offered for research-use-only and, subject to FDA clearance, will be released to CLIA certified laboratories for the generation and implementation of LDTs. For more information on the MassARRAY Analyzer 4 see http://www.massarrayanalyzer.com.
The company launched the SensiGene(TM) RHD Genotyping and the Fetal Sex Determination tests in February 2010. Both of these new tests detect and analyze circulating cell-free fetal (ccff) DNA. The SensiGene RHD Genotyping test examines multiple regions of the gene that is known to be the most common genetic basis of RhD negative phenotypes. In addition to quality control metrics to ensure accuracy both tests also utilize a fetal identifier control assay to verify the presence of fetal DNA, in particular for RhD negative, female fetuses.
Litigation Update - On May 3, 2010, the U.S. District Court for the Southern District of California entered an order approving the final approval of a stipulation of settlement reached in the class action securities lawsuits related to alleged violations of federal securities laws consolidated under the caption In re Sequenom Inc. Securities Litigation. Even though the settlement has received final approval from the court, the court's approval may be subject to appeal and will not become effective until the time for appeals has lapsed without any appeal. If the settlement becomes effective, Sequenom will issue approximately 6.8 million shares of its common stock in connection with the settlement.
On May 6, 2010, Sequenom and the individual defendants entered into a stipulation of settlement that will resolve all of the pending derivative actions. The stipulation of settlement remains subject to approval by the U.S. District Court and the Superior Court of California. Subject to final approval of the stipulation of settlement, in exchange for a release of all claims by the plaintiffs and a dismissal of the derivative actions, Sequenom has agreed (i) to adopt or continue certain corporate governance measures and (ii) to pay the plaintiffs' attorneys a total of $2.5 million. A significant portion of the attorney's fees is to be paid by its insurance carriers. Sequenom has the right to elect to issue up to 200,000 shares of its common stock to pay its portion of the attorneys' fees.
In October 2009, plaintiff Xenomics, Inc. (now known as TrovaGene) filed a complaint in the Supreme Court of the State of New York naming Sequenom as the defendant alleging that Sequenom had breached the license agreement entered into by the parties on October 29, 2008, which provides Sequenom with exclusively licensed patent rights for the use of fetal nucleic acids obtained from maternal urine, and that the plaintiff has suffered damages as a result. In December 2009, Sequenom removed the case to the U.S. District Court for the Southern District of New York. On May 4, 2010, the district court granted the Sequenom's motion to dismiss the action because the license agreement specifically provides that if TrovaGene seeks to resolve a dispute arising under the agreement, it must do so by commencing an arbitration in San Diego. TrovaGene has not notified Sequenom whether it would appeal the dismissal or commence arbitration proceedings in San Diego.

Monday, May 3, 2010

Pompe’s Disease & Harrison Ford's Extraordinary Measures Movie

If you are to watch just one movie this year (an that includes the movies from last year), don’t get hooked on Watmen, Avatar, Up in the Air or other great blockbusters.  These movies are awesome, but you won’t come out of the movie with any value.  One movie to watch this year is Harrison Ford’s “Extraordinary Measures”.

Most critics give this movie low ratings. Just two or three stars out of five and discuss Ford’s acting and playing on public sentiment. But what the critics don’t see are two things:

1. The movie shows how bad the Pompe disease is and how important prenatal diagnostics are in our lives.

2. It shows an example of a successful biotech startup and technology progression from academia into the biotech industry, then into biopharma and then into the clinic. The movie is based on a real story of John Crawley, a father of two Pompe disease children, who started up a biotech company focusing on developing the enzyme replacement therapy, which was later acquired by Genzyme, which developd a working treatment.

Regardless how bad the acting is, this movie brings value. 

Pompe disease occurs in about 1 in 40,000 births. But since most patients don’t make it through the first year after birth and the treatment costs $300,000 per year for the rest of the patient’s life, there are only about 5,000 to 10,000 suffers of this disease.


It is extremely important to do genetic testing before conception and at the pre-implantation or prenatal level.
When both parents are carriers of the defective alpha-glucosidase gene, there is one in four chance of giving birth to the Pompe disease child and two in four chance of giving birth to the carrier of the defective gene. It is possible to avoid this by genetic analysis of both parents before conception. 

The image to the left is taken from the Tribune website. 

There should be more movies like “Extraordinary Measures”. Movie companies are too focused on creating war movies, dirty humor comedies and bloody vampire fairitales and ignore skripts that can positively influence the younger generations. There should be more movies made on genetic analysis and prenatal diagnostics.

One such skript can cover the story of Sequenom (Nasdaq: SQNM) and the colorful biography of its founder, Dr. Charles Cantor. I am sure that in a few years this company will also launch the Pompe disease test. Currently they are focusing on Down Syndrome.

Saturday, May 1, 2010

Blood-sucking animals can exchange genetic material with mammals

Interesting article in Science Daily today (based on a very credible publication in Nature). It looks like the blood-sucking animals can exchange genetic material with their hosts. Scary stuff.
If you think about it, anything that integrates into your genome (including your own transposons) can alter some of the cancer-fighting genes. So ultimately, these mosquito bites May lead to cancer.

Well, one thing is clear. You should avoid mosquito bites during pregnancy just to be on the safe side.

Here is the article: 
Scientists Uncover Transfer of Genetic Material Between Blood-Sucking Insect and Mammals
ScienceDaily (Apr. 30, 2010) — Researchers at The University of Texas at Arlington have found the first solid evidence of horizontal DNA transfer, the movement of genetic material among non-mating species, between parasitic invertebrates and some of their vertebrate hosts.

The findings are published in the April 28 issue of the journal Nature, one of the world's foremost scientific journals.
Genome biologist Cédric Feschotte and postdoctoral researchers Clément Gilbert and Sarah Schaack found evidence of horizontal transfer of transposon from a South American blood-sucking bug and a pond snail to their hosts. A transposon is a segment of DNA that can replicate itself and move around to different positions within the genome. Transposons can cause mutations, change the amount of DNA in the cell and dramatically influence the structure and function of the genomes where they reside.
"Since these bugs frequently feed on humans, it is conceivable that bugs and humans may have exchanged DNA through the mechanism we uncovered. Detecting recent transfers to humans would require examining people that have been exposed to the bugs for thousands of years, such as native South American populations," Feschotte said.
Data on the insect and the snail provide strong evidence for the previously hypothesized role of host-parasite interactions in facilitating horizontal transfer of genetic material. Additionally, the large amount of DNA generated by the horizontally transferred transposons supports the idea that the exchange of genetic material between hosts and parasites influences their genomic evolution.
"It's not a smoking gun, but it is as close to it as you can get," Feschotte said
The infected blood-sucking triatomine, causes Chagas disease by passing trypanosomes (parasitic protozoa) to its host. Researchers found the bug shared transposon DNA with some hosts, namely the opossum and the squirrel monkey. The transposons found in the insect are 98 percent identical to those of its mammal hosts.
The researchers also identified members of what Feschotte calls space invader transposons in the genome of Lymnaea stagnalis, a pond snail that acts as an intermediate host for trematode worms, a parasite to a wide range of mammals.
The long-held theory is that mammals obtain genes vertically, or handed down from parents to offspring. Bacteria receive their genes vertically and also horizontally, passed from one unrelated individual to another or even between different species. Such lateral gene transfers are frequent in bacteria and essential for rapid adaptation to environmental and physiological challenges, such as exposure to antibiotics.
Until recently, it was not known horizontal transfer could propel the evolution of complex multicellular organisms like mammals. In 2008, Feschotte and his colleagues published the first unequivocal evidence of horizontal DNA transfer.
Millions of years ago, tranposons jumped sideways into several mammalian species. The transposon integrated itself into the chromosomes of germ cells, ensuring it would be passed onto future generations. Thus, parts of those mammals' DNA did not descend from their common ancestors, but were acquired laterally from another species.
The actual means by which transposons can spread across widely diverse species has remained a mystery.
"When you are trying to understand something that occurred over thousands or millions of years ago, it is not possible to set up a laboratory experiment to replicate what happened in nature," Feschotte said.
Instead, the researchers made their discovery using computer programs designed to compare the distribution of mobile genetic elements among the 102 animals for which entire genome sequences are currently available. Paul J. Brindley of George Washington University Medical Center in Washington, D.C., contributed tissues and DNA used to confirm experimentally the computational predictions of Feschotte's team.
When the human genome was sequenced a decade ago, researchers found that nearly half of the human genome is derived from transposons, so this new knowledge has important ramifications for understanding the genetics of humans and other mammals.
Feschotte's research is representative of the cutting edge research that is propelling UT Arlington on its mission of becoming a nationally recognized research institution.
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Adapted from materials provided by University of Texas at Arlington.

Journal Reference:
1.    Clément Gilbert, Sarah Schaack, John K. Pace II, Paul J. Brindley, Cédric Feschotte. A role for host-parasite interactions in the horizontal transfer of transposons across phyla. Nature, 2010; 464 (7293): 1347 DOI: 10.1038/nature08939

New Recommendations for Down Syndrome: Screening Should Be Offered to All Pregnant Women (2007)

The ASOG recommendation is two years old, but is as current as it can be. Every pregnant woman should get tested for Down Syndrome



ACOG NEWS RELEASE

New Recommendations for Down Syndrome: Screening Should Be Offered to All Pregnant Women

Washington, DC -- All pregnant women, regardless of their age, should be offered screening for Down syndrome, according to a new Practice Bulletin issued today by The American College of Obstetricians and Gynecologists (ACOG). Previously, women were automatically offered genetic counseling and diagnostic testing for Down syndrome by amniocentesis or chorionic villus sampling (CVS) if they were 35 years and older.

The new ACOG guidelines recommend that all pregnant women consider less invasive screening options for assessing their risk for Down syndrome, a common disorder that is caused by an extra chromosome and can result in congenital heart defects and mental retardation. Screening for Down syndrome should occur before the 20th week of pregnancy.

"This new recommendation says that the maternal age of 35 should no longer be used by itself as a cut-off to determine who is offered screening versus who is offered invasive diagnostic testing," noted Deborah Driscoll, MD, a lead author of the document and vice chair of ACOG's Committee on Practice Bulletins-Obstetrics, which developed the Practice Bulletin with ACOG's Committee on Genetics and the Society for Maternal-Fetal Medicine.

ACOG also advises that all pregnant women, regardless of their age, should have the option of diagnostic testing. ACOG recognizes that a woman's decision to have an amniocentesis or CVS is based on many factors, such as a family or personal history of birth defects, the risk that the fetus will have a chromosome abnormality or an inherited condition, and the risk of pregnancy loss from an invasive procedure.

According to the new guidelines, the goal is to offer screening tests with high detection rates and low false positive rates that also provide patients with diagnostic testing options if the screening test indicates that the patient is at an increased risk for having a child with Down syndrome. Because of the number of multiple screening strategies currently available, the document provides ob-gyns with some suggested screening strategies that they can choose to offer in their practice to best meet the needs of their patients. The guidelines discuss the advantages and disadvantages of each screening test and some of the factors that determine which screening test should be offered, including gestational age at first prenatal visit, number of fetuses, previous obstetrical and family history, and availability of various screening tests.

The following ACOG recommendations are based on good and consistent scientific evidence:

* First-trimester screening using both nuchal translucency (NT), an ultrasound exam that measures the thickness at the back of the neck of the fetus, and a blood test is an effective screening test in the general population and is more effective than NT alone.
* Women found to be at increased risk of having a baby with Down syndrome with first-trimester screening should be offered genetic counseling and the option of CVS or mid-trimester amniocentesis.
* Specific training, standardization, use of appropriate ultrasound equipment, and ongoing quality assessment are important to achieve optimal NT measurement for Down syndrome risk assessment, and this procedure should be limited to centers and individuals meeting this criteria.
* Neural tube defect screening should be offered in the mid-trimester to women who elect only first-trimester screening for Down syndrome.

Practice Bulletin #77, "Screening for Fetal Chromosomal Abnormalities," is published in the January 2007 issue of Obstetrics & Gynecology.



Source: The American College of Obstetricians and Gynecologists is the national medical organization representing over 51,000 members who provide health care for women.
http://www.acog.org/from_home/publications/press_releases/nr01-02-07-1.cfm