IRVINE, Calif.—Molecular diagnostics company CombiMatrix Corp. announced in April the launch of a new offering: CombiPGD–Preimplantation Genetic Diagnosis (PGD) for single-gene disorders and chromosomal translocations. The test is performed before embryo implantation to identify genetic defects created via in-vitro fertilization (IVF) to prevent certain diseases or disorders from being passed on.
“We are pleased to launch another incremental revenue-producing test in the IVF market that meets a critical clinical need. The CombiPGD test rounds out our IVF test offering, where we also offer PGS [pre-implantation genetic screening] testing, parental karyotyping and miscarriage analysis testing,” Mark McDonough, president and CEO of CombiMatrix, commented in a statement. “CombiPGD allows couples who are at significant risk of having a child with a serious disorder the opportunity to gain important information about their embryos before implantation with the goal of implanting only those embryos without the disease of concern.”
CombiMatrix notes that its CombiPGD approach offers broad applicability and streamlined implementation. Rather than developing and validating PCR probes for each individual disease gene, CombiMatrix uses a genome-wide set of single nucleotide polymorphisms as markers to “track” genes with mutations from parent to child. In addition to making it possible for this test to be used for almost any single-gene disorder, it also shortens the standard eight- to 12-week waiting period for test development to under three weeks.
In terms of single-gene disorders, CombiMatrix notes that “Individuals who are identified as carriers of a recessive disorder or who are at risk for/have a dominant genetic disorder are at increased risk of having an affected child. Using DNA samples from your patient, her partner and a reference family member, PGD determines the unique chromosomal background of the disease-causing mutation(s), and utilizes this information to determine the disease status of an embryo.” Examples of single-gene disorders, also known as Mendelian disorders, include cystic fibrosis, Huntington’s disease and sickle cell disease.
Chromosome translocations are unusual arrangements of chromosomes, and occur when “a change has arisen during the making of the egg or the sperm or around the time of conception” or when “an altered chromosome arrangement has been inherited from either the mother or the father,” according to EuroGentest, a project funded by the European Commission. A balanced chromosome translocation is one in which chromosomes are rearranged but no genetic material is lost or gained. Roughly one in 500 people have translocations, as noted on the EuroGentest website. CombiMatrix explains that despite the fact that people who have a balanced chromosomal translocation don’t generally present with symptoms, “their gametes have a significantly increased chance of carrying a chromosomal imbalance.”
This test joins other implantation/fertilization testing options in CombiMatrix’s portfolio, including CombiPGS, which may help decrease the rate of implantation failure and miscarriage by enabling physicians to identify and transfer chromosomally normal embryos. The test uses chromosomal microarray analysis to assess embryos for chromosomal abnormalities, such as segmental aneuploidy and whole chromosome aneuploidy, which is the most common cause of failed implantation and/or early miscarriage. CombiMatrix notes on its website that “Chromosomal abnormalities are one of the most common reasons for implantation failure and miscarriages that occur within the first 12 weeks of pregnancy. In fact, approximately 50 to 60 percent of miscarriages that occur in the first trimester are due to a fetal chromosomal abnormality. Chromosomally abnormal embryos may not differ in overall microscopic appearance from chromosomally normal embryos, making it difficult to identify which embryo(s) have the best chance of resulting in a healthy baby. By implanting a chromosomally normal embryo, the possibility of a successful implantation and pregnancy is significantly enhanced.”
“In the last few years, we have witnessed an exponential rise in the use of carrier screening for inherited genetic diseases among patients of reproductive age,” said Dr. Matthew C. Goering, a member of CombiMatrix’s scientific advisory board, director of Clinical Embryology at the Center for Advanced Reproductive Medicine at the University of Kansas and assistant professor at the University of Kansas Department of Obstetrics and Gynecology Division of Reproductive Endocrinology and Infertility. “This growth in procreative genetic screening, along with improvements in the technology and success rates associated with IVF and embryo biopsy, have led to a significant increase in the demand for preimplantation genetic testing in our IVF practice. Genetic testing of this type is inherently challenging due to the astonishingly small size of the samples—typically just a few cells from each embryo. Thus, as the demand for this new technology has risen, so has the need for high-quality, experienced, genetic diagnostic laboratories that offer the service.”
