preimplantation genetic diagnosis
- preimplantation genetic diagnosis
a diagnostic procedure carried out on embryos at the earliest stage of development, before implantation in the uterus. Access to these early embryos requires the in vitro fertilization of egg cells: three days after fertilization one or two cells are aspirated from the six-cell embryo; alternatively, tissue is removed from an embryo at five or six days, when it has reached the blastocyst stage. Isolated cells can then be genetically analysed, allowing the transfer of selected embryos to the mother. One of the major applications of PGD is for the detection (using the FISH technique) of chromosomal abnormalities, especially aneuploidies (e.g. Down's syndrome), and the procedure is used mainly in women who have had repeated miscarriages or have failed to achieve pregnancy after several IVF treatment cycles, which could be due to the presence of such abnormalities in the embryo. PGD can also be used to detect defective genes responsible for hereditary disorders (e.g. the commonest form of cystic fibrosis, Huntington's disease) and genes associated with susceptibility to certain cancers. When a defect is detected, genetic counselling is offered.
The new mediacal dictionary.
2014.
Look at other dictionaries:
Preimplantation genetic diagnosis — In medicine and (clinical) genetics preimplantation genetic diagnosis (PGD) (or also known as Embryo Screening) refers to procedures that are performed on embryos prior to implantation, sometimes even on oocytes prior to fertilization. PGD is… … Wikipedia
preimplantation genetic diagnosis — (PGD) see prenatal diagnosis … Medical dictionary
preimplantation genetic diagnosis — (PGD) in assisted reproductive technology, the determination of chromosomal abnormalities in the embryo before it is transferred to the uterus … Medical dictionary
Preimplantation genetic haplotyping — (PGH) is a clinical method of preimplantation genetic diagnosis (PGD). PGH was first developed in 2006 at London s Guy s Hospital and greatly advances PGD by using DNA fingerprinting rather than identifying the actual genetic signature (such as… … Wikipedia
Genetic testing — (also called DNA based tests) is among the newest and most sophisticated of techniques[1] used to test for genetic disorders which involves direct examination of the DNA molecule itself. Other genetic tests include biochemical tests for such gene … Wikipedia
Preimplantation diagnosis — is the act of checking an ovum, zygote, or blastocyst for defects or diseases by cytogenetics before implanting into a womb. Preimplantation diagnosis takes place before prenatal diagnosis, which refers to a checking for defects in a fetus or… … Wikipedia
genetic screening — screening tests to discover individuals whose genotypes are associated with specific diseases. Such individuals may later develop the disease itself or pass it on to their children (see carrier). The recent use of genetic screening to diagnose… … The new mediacal dictionary
Prenatal diagnosis — Diagnosis before birth. Methods for prenatal diagnosis include ultrasound of the uterus, placenta, and/or developing fetus; chorionic villus sampling (CVS) to obtain tissue for chromosome or biochemical analysis; and amniocentesis to obtain… … Medical dictionary
Genetic disorder — For a non technical introduction to the topic, see Introduction to genetics. Genetic disorder Classification and external resources MeSH D030342 A genetic disorder is an illness caused by abnormalities in genes or … Wikipedia
Medical diagnosis — (often simply termed diagnosis) refers both to the process of attempting to determine and/or identify a possible disease or disorder (and diagnosis in this sense can also be termed (medical) diagnostic procedure), and to the opinion reached by… … Wikipedia
