Researchers Develop New Procedure to Screen All 46 Human Chromosomes to Identify Abnormalities in Embryos

New technology developed by researchers at Reproductive Medicine Associates

of New Jersey awarded General Program Prize Paper at American Society for

Reproductive Medicine Annual Meeting

Oct 18, 2007, 01:00 ET from Reproductive Medicine Associates of New Jersey

    WASHINGTON and MORRISTOWN, N.J., Oct. 18 /PRNewswire/ -- Researchers at
 Reproductive Medicine Associates of New Jersey (RMA) received the highest
 award for research at the American Society for Reproductive Medicine (ASRM)
 for developing a novel technology making it possible to provide accurate,
 rapid analysis of all 46 human chromosomes from a single cell taken from a
 human embryo. The ASRM Prize Paper Award is awarded to the most significant
 research in the field of human reproduction each year. This new technology
 makes it possible for the first time to fully evaluate the genetic make up
 of human embryos in a time frame which allows clinicians and scientists to
 use that information to help improve pregnancy rates, reduce miscarriage
 risk, and decrease the risk of some major congenital anomalies such as Down
     This procedure, known as "Accurate 23 chromosome aneuploidy screening
 in human blastomeres using single nucleotide polymorphisms (SNP)," provides
 fertility specialists for the first time with a rapid and accurate
 technique to assess the genetic normality of human embryos created through
 in vitro fertilization (IVF).
     The results of this research effort were presented this week at the
 American Society for Reproductive Medicine (ASRM) meeting and were awarded
 the General Program Prize Paper Award, the highest award provided by this
 international professional society. Nathan Treff, Ph.D., lead author on the
 study and a researcher in molecular genetics at RMA, delivered the results
 in an oral presentation. "Accurate and rapid identification of
 chromosomally- abnormal (aneuploid) embryos within hours after embryo
 biopsy will provide physicians with the ability to select embryos for
 transfer to the uterus based on a far more complete and accurate picture of
 their genetic health than has ever been possible," said Dr. Treff. "This
 could, in turn, allow us to reduce the number of embryos implanted while
 increasing the chances that couples treated with IVF will have a healthy
     It has been known for more than a decade that the principal reason
 human embryos fail to implant relates to the embryo having too much or too
 little genetic material. One example is Down syndrome where the embryo
 contains an extra chromosome 21. While that error is commonly known, the
 addition or loss of other chromosomes also occurs frequently, but those
 embryos generally arrest prior to implantation or result in early
 miscarriage. Unfortunately, genetically normal and abnormal embryos
 typically appear the same during the first few days of development. This
 means that embryologists and physicians cannot observe a given group of
 embryos and distinguish which are normal and have an excellent chance of
 implanting and developing into a healthy child from those which are
 abnormal and do not possess significant reproductive potential. A specific
 genetic screening test of each embryo is required.
     Currently, the most commonly used technology for chromosomal analysis
 of embryos (sometimes termed preimplantation genetic diagnosis or PGD), is
 florescent in situ hybridization (FISH). This technique assesses fewer than
 half of the 23 chromosome pairs found in the human karyotype and has a
 suboptimal error rate. This makes it possible for many genetic
 abnormalities to go undetected. Prior technologies that have attempted to
 analyze all 23 chromosome pairs have not been useful because of the length
 of time required to provide accurate results.
     "This groundbreaking research paves the way for more successful IVF
 treatments," says Dr. Richard T. Scott, founding partner of RMA. "Human
 embryos must implant within the first few days in order to achieve a
 pregnancy. This new technology developed at RMA combines for the first time
 both high accuracy and efficiency in embryonic chromosomal analysis with
 rapid assessment in a clinically-useful time frame."
     In this new process, a single cell is removed from an embryo on the
 third day of embryonic development. The 3 billion base-pairs of nucleic
 acid that make up a single copy of human DNA weigh only 6 trillionths of a
 gram, which is too small to allow analysis. It is necessary first to copy
 this code over one million times with great fidelity to accumulate
 sufficient DNA to accurately analyze the number of chromosomes present in
 the cell. This step, termed whole genomic amplification (WGA), one of many
 technologically demanding steps required for this process, has been refined
 extensively by the team at RMA. Once amplified, approximately 250,000
 different areas of the DNA, called single nucleotide polymorphisms (SNPs,
 or "snips") are individually examined and assigned a specific copy number.
 These copy numbers are then collated for each chromosome and the number of
 each individual chromosome calculated.
     This process makes it possible to identify any deviation from the
 normal copy number of two for each chromosome pair in a developing embryo.
 Copy numbers of "one" or "three or more" indicate a chromosomally-abnormal
 embryo which would generally not implant but which may implant and lead to
 subsequent miscarriage or, rarely, result in the birth of an anomalous
 child. This technology should improve delivery rates of healthy children
 for some couples who are infertile or who experience recurrent miscarriage.
     About RMA
     Reproductive Medicine Associates (RMA) of New Jersey is one of the
 world's leading centers for treatment and research in reproductive
 medicine. RMA's founding partners and physicians have helped bring more
 than 17,000 babies to loving parents. RMA is also world-renowned for having
 one of the highest success rates in the treatment of infertility.

SOURCE Reproductive Medicine Associates of New Jersey