 | This article contains content that is written like an advertisement .(January 2024) |
Ravgen Inc. is a privately owned biotech company founded in 2000 by Chairman and C.E.O. Dr. Ravinder Dhallan. [1] Ravgen Inc. performs research in the prenatal diagnostic field and has developed non-invasive prenatal diagnosis testing for Down Syndrome. [2]
Ravgen has published peer-reviewed articles on genetic research in publications such as the Journal of the American Medical Association in 2004, [3] The Lancet in 2007, [4] and the New England Journal of Medicine in 2012. [5] In addition, Ravgen has received some acclaim from its research on non-invasive prenatal DNA testing. [6]
Down syndrome or Down's syndrome, also known as trisomy 21, is a genetic disorder caused by the presence of all or part of a third copy of chromosome 21. It is usually associated with developmental delays, mild to moderate intellectual disability, and characteristic physical features. There are three types of Down syndrome, the most common being trisomy 21. Mosaic Down syndrome accounts for two per cent of Down syndrome cases, and Translocation Down syndrome accounts for three per cent of cases.
Amniocentesis is a medical procedure used primarily in the prenatal diagnosis of genetic conditions. It has other uses such as in the assessment of infection and fetal lung maturity. Prenatal diagnostic testing, which includes amniocentesis, is necessary to conclusively diagnose the majority of genetic disorders, with amniocentesis being the gold-standard procedure after 15 weeks' gestation.
Rh disease is a type of hemolytic disease of the fetus and newborn (HDFN). HDFN due to anti-D antibodies is the proper and currently used name for this disease as the Rh blood group system actually has more than 50 antigens and not only the D-antigen. The term "Rh Disease" is commonly used to refer to HDFN due to anti-D antibodies, and prior to the discovery of anti-Rho(D) immune globulin, it was the most common type of HDFN. The disease ranges from mild to severe, and occurs in the second or subsequent pregnancies of Rh-D negative women when the biologic father is Rh-D positive.
Prenatal testing is a tool that can be used to detect some birth defects at various stages prior to birth. Prenatal testing consists of prenatal screening and prenatal diagnosis, which are aspects of prenatal care that focus on detecting problems with the pregnancy as early as possible. These may be anatomic and physiologic problems with the health of the zygote, embryo, or fetus, either before gestation even starts or as early in gestation as practicable. Screening can detect problems such as neural tube defects, chromosome abnormalities, and gene mutations that would lead to genetic disorders and birth defects, such as spina bifida, cleft palate, Down syndrome, trisomy 18, Tay–Sachs disease, sickle cell anemia, thalassemia, cystic fibrosis, muscular dystrophy, and fragile X syndrome. Some tests are designed to discover problems which primarily affect the health of the mother, such as PAPP-A to detect pre-eclampsia or glucose tolerance tests to diagnose gestational diabetes. Screening can also detect anatomical defects such as hydrocephalus, anencephaly, heart defects, and amniotic band syndrome.
Chorionic villus sampling (CVS), sometimes called "chorionic villous sampling", is a form of prenatal diagnosis done to determine chromosomal or genetic disorders in the fetus. It entails sampling of the chorionic villus and testing it for chromosomal abnormalities, usually with FISH or PCR. CVS usually takes place at 10–12 weeks' gestation, earlier than amniocentesis or percutaneous umbilical cord blood sampling. It is the preferred technique before 15 weeks.
The triple test, also called triple screen, the Kettering test or the Bart's test, is an investigation performed during pregnancy in the second trimester to classify a patient as either high-risk or low-risk for chromosomal abnormalities.
Large for gestational age (LGA) is a term used to describe infants that are born with an abnormally high weight, specifically in the 90th percentile or above, compared to other babies of the same developmental age. Macrosomia is a similar term that describes excessive birth weight, but refers to an absolute measurement, regardless of gestational age. Typically the threshold for diagnosing macrosomia is a body weight between 4,000 and 4,500 grams, or more, measured at birth, but there are difficulties reaching a universal agreement of this definition.
The Pallister–Killian syndrome (PKS), also termed tetrasomy 12p mosaicism or the Pallister mosaic aneuploidy syndrome, is an extremely rare and severe genetic disorder. PKS is due to the presence of an extra and abnormal chromosome termed a small supernumerary marker chromosome (sSMC). sSMCs contain copies of genetic material from parts of virtually any other chromosome and, depending on the genetic material they carry, can cause various genetic disorders and neoplasms. The sSMC in PKS consists of multiple copies of the short arm of chromosome 12. Consequently, the multiple copies of the genetic material in the sSMC plus the two copies of this genetic material in the two normal chromosome 12's are overexpressed and thereby cause the syndrome. Due to a form of genetic mosaicism, however, individuals with PKS differ in the tissue distributions of their sSMC and therefore show different syndrome-related birth defects and disease severities. For example, individuals with the sSMC in their heart tissue are likely to have cardiac structural abnormalities while those without this sSMC localization have a structurally normal heart.
A nuchal scan or nuchal translucency (NT) scan/procedure is a sonographic prenatal screening scan (ultrasound) to detect chromosomal abnormalities in a fetus, though altered extracellular matrix composition and limited lymphatic drainage can also be detected.
Noninvasive genotyping is a modern technique for obtaining DNA for genotyping that is characterized by the indirect sampling of specimen, not requiring harm to, handling of, or even the presence of the organism of interest. Beginning in the early 1990s, with the advent of PCR, researchers have been able to obtain high-quality DNA samples from small quantities of hair, feathers, scales, or excrement. These noninvasive samples are an improvement over older allozyme and DNA sampling techniques that often required larger samples of tissue or the destruction of the studied organism. Noninvasive genotyping is widely utilized in conservation efforts, where capture and sampling may be difficult or disruptive to behavior. Additionally, in medicine, this technique is being applied in humans for the diagnosis of genetic disease and early detection of tumors. In this context, invasivity takes on a separate definition where noninvasive sampling also includes simple blood samples.
Maternal–fetal medicine (MFM), also known as perinatology, is a branch of medicine that focuses on managing health concerns of the mother and fetus prior to, during, and shortly after pregnancy.
Trisomy 16 is a chromosomal abnormality in which there are 3 copies of chromosome 16 rather than two. It is the most common trisomy leading to miscarriage and the second most common chromosomal cause of it, closely following X-chromosome monosomy. About 6% of miscarriages have trisomy 16. Those mostly occur between 8 and 15 weeks after the last menstrual period.
Sequenom, Inc. is an American company based in San Diego, California. It develops enabling molecular technologies, and highly sensitive laboratory genetic tests for NIPT. Sequenom's wholly owned subsidiary, Sequenom Center for Molecular Medicine (SCMM), offers multiple clinical molecular genetics tests to patients, including MaterniT21, plus a noninvasive prenatal test for trisomy 21, trisomy 18, and trisomy 13, and the SensiGene RHD Fetal RHD genotyping test.
Prenatal sex discernment is the prenatal testing for discerning the sex of a fetus before birth.
Ravinder (Rav) Dhallan is the chairman and chief executive officer of Ravgen.
Cell-free fetal DNA (cffDNA) is fetal DNA that circulates freely in the maternal blood. Maternal blood is sampled by venipuncture. Analysis of cffDNA is a method of non-invasive prenatal diagnosis frequently ordered for pregnant women of advanced maternal age. Two hours after delivery, cffDNA is no longer detectable in maternal blood.
Dennis Yuk Ming Lo is a Hong Kong molecular biologist, and an important contributor to the development of non-invasive prenatal testing. He is the current Associate Dean (Research) and Li Ka Shing Professor of Medicine at the Chinese University of Hong Kong (CUHK), as well as the head of the Department of Chemical Pathology of CUHK and the director of the Li Ka Shing Institute of Health Sciences. His research focuses on the detection of cell-free fetal DNA in blood plasma.
Diana W. Bianchi is the director of the U.S. National Institutes of Health Eunice Kennedy Shriver National Institute of Child Health and Human Development, a post often called “the nation’s pediatrician.” She is a medical geneticist and neonatologist noted for her research on fetal cell microchimerism and prenatal testing. Bianchi had previously been the Natalie V. Zucker Professor of Pediatrics, Obstetrics, and Gynecology at Tufts University School of Medicine and founder and executive director of the Mother Infant Research Institute at Tufts Medical Center. She also has served as Vice Chair for Research in the Department of Pediatrics at the Floating Hospital for Children at Tufts Medical Center.
Noninvasive prenatal testing (NIPT) is a method used to determine the risk for the fetus being born with certain chromosomal abnormalities, such as trisomy 21, trisomy 18 and trisomy 13. This testing analyzes small DNA fragments that circulate in the blood of a pregnant woman. Unlike most DNA found in the nucleus of a cell, these fragments are not found within the cells, instead they are free-floating, and so are called cell free fetal DNA (cffDNA). These fragments usually contain less than 200 DNA building blocks and arise when cells die, and their contents, including DNA, are released into the bloodstream. cffDNA derives from placental cells and is usually identical to fetal DNA. Analysis of cffDNA from placenta provides the opportunity for early detection of certain chromosomal abnormalities without harming the fetus.
Dame Lyn Susan Chitty is a British physician and Professor of Genetics and Fetal Medicine at University College London. She is the deputy director of the National Institute for Health and Care Research Great Ormond Street Hospital Biomedical Research Centre. She is the 2022 president of the International Society for Prenatal Diagnosis. Her research considers non-invasive prenatal diagnostics. She was made a Dame in the 2022 New Year Honours.