Preimplantation genetic diagnosis

Preimplantation Genetic Diagnosis (PGD) is a reproductive technology used with an in vitro fertilization (IVF) cycle to increase the potential for a successful pregnancy and birth. PGD involves the genetic profiling of embryos prior to implantation and is used to screen for specific genetic conditions or chromosomal abnormalities.

History

The development of PGD began in the late 1980s. The first successful use of PGD was reported in 1990 by Alan Handyside and his team at the Hammersmith Hospital in London. This breakthrough allowed for the detection of cystic fibrosis in embryos, leading to the birth of a healthy child free from the disease.

Procedure

The PGD process involves several steps: 1. **Ovarian Stimulation**: The female partner undergoes ovarian stimulation to produce multiple eggs. 2. **Egg Retrieval**: The eggs are retrieved from the ovaries. 3. **Fertilization**: The eggs are fertilized with sperm in the laboratory to create embryos. 4. **Embryo Biopsy**: A few cells are removed from each embryo for genetic testing. 5. **Genetic Analysis**: The cells are analyzed for specific genetic conditions or chromosomal abnormalities. 6. **Embryo Transfer**: Embryos that are free of genetic conditions are selected for transfer to the uterus.

Applications

PGD is used for various purposes, including:

• **Screening for Genetic Disorders**: PGD can detect single-gene disorders such as Tay-Sachs disease, Huntington's disease, and sickle cell anemia.
• **Chromosomal Abnormalities**: PGD can identify chromosomal abnormalities such as Down syndrome and Turner syndrome.
• **HLA Matching**: PGD can be used to select embryos that are a human leukocyte antigen (HLA) match for a sibling requiring a stem cell transplant.
• **Sex Selection**: PGD can determine the sex of the embryo, which can be used for family balancing or to avoid sex-linked genetic disorders.

Ethical Considerations

The use of PGD raises several ethical issues, including:

• **Designer Babies**: Concerns about the potential for selecting non-medical traits such as intelligence or physical appearance.
• **Accessibility**: The high cost of PGD may limit access to the technology for some individuals or couples.
• **Disability Rights**: The use of PGD to prevent the birth of children with disabilities has sparked debate within the disability rights community.

Regulation

The regulation of PGD varies by country. In the United States, PGD is regulated by the Food and Drug Administration (FDA) and the Centers for Disease Control and Prevention (CDC). In the United Kingdom, PGD is regulated by the Human Fertilisation and Embryology Authority (HFEA).

See Also

• In vitro fertilization
• Genetic counseling
• Prenatal diagnosis
• Assisted reproductive technology