Question 1

What is the Meaning of Preimplantation Genetic Diagnosis?

Accepted Answer

Preimplantation Genetic Diagnosis (PGD) is a specialized genetic test on embryos created via in vitro fertilization before uterine transfer. It identifies specific genetic conditions or chromosomal abnormalities within early-stage embryos. PGD allows prospective parents, carriers of genetic disorders, to select embryos free from particular genetic concerns, preventing disease transmission.

Question 2

What is the Context of Preimplantation Genetic Diagnosis?

Accepted Answer

PGD operates within assisted reproductive technologies, following oocyte fertilization in a laboratory. It applies to early-stage embryos, typically blastomere or trophectoderm stage, prior to uterine implantation. This intervention prevents vertical transmission of known genetic disorders, making it a key component of family planning for at-risk couples.

Question 3

What is the Significance of Preimplantation Genetic Diagnosis?

Accepted Answer

PGD's clinical importance lies in significantly reducing severe genetic diseases in children born to affected parents or carriers. It offers prospective parents a proactive measure to avoid medical and emotional challenges linked to debilitating genetic conditions, promoting healthier reproductive outcomes. This diagnostic tool directly impacts patient well-being by mitigating inherited genetic risks.

Question 4

What is the Mechanism of Preimplantation Genetic Diagnosis?

Accepted Answer

PGD involves obtaining few cells from an embryo without compromising its developmental potential. These biopsied cells undergo genetic analysis using techniques like polymerase chain reaction for single gene disorders or comprehensive chromosomal screening. The genetic profile of each embryo is determined, identifying those carrying the specific genetic variant or aneuploidy.

Question 5

What is the Application of Preimplantation Genetic Diagnosis?

Accepted Answer

PGD is applied in clinical practice for couples at high risk of transmitting monogenic disorders (e.g., cystic fibrosis, Huntington's disease) or with recurrent miscarriages due to chromosomal abnormalities. The protocol involves in vitro fertilization, embryo biopsy, genetic testing, and subsequent transfer of unaffected embryos. It offers a precise approach to reproductive risk management.

Question 6

What is the Metric of Preimplantation Genetic Diagnosis?

Accepted Answer

PGD effectiveness is assessed by successful identification of unaffected embryos, subsequent implantation rates, and live birth rate of healthy, genetically screened infants. Clinical monitoring tracks biopsied embryos, diagnostic accuracy of genetic tests, and ongoing health of children born following PGD. The ultimate metric is birth of a child free from the targeted genetic condition.

Question 7

What is the Risk of Preimplantation Genetic Diagnosis?

Accepted Answer

Potential PGD risks include low embryo damage during biopsy, potentially reducing viability or implantation. A small chance of misdiagnosis, false positive or negative, often necessitates prenatal diagnosis for confirmation. Not all embryos may be suitable for transfer, causing emotional distress. The procedure carries general IVF risks, such as ovarian hyperstimulation syndrome.

Preimplantation Genetic Diagnosis

Meaning

Context

Significance

Mechanism

Application

Metric

Risk

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