PGD Medical Abbreviation
PGD stands for Preimplantation Genetic Diagnosis (or Testing), a reproductive technology used during in vitro fertilization (IVF) to test embryos for genetic abnormalities before transfer to the uterus. 1, 2
Core Definition and Terminology
- PGD is now often referred to as PGT (Preimplantation Genetic Testing), with the terminology evolving to reflect different applications 1, 2
- The procedure involves genetic analysis of embryos created through IVF before implantation, allowing selection of unaffected embryos 3, 4
- Testing is typically performed on 1-2 cells (blastomeres) biopsied from embryos at the 6-8 cell stage (day 3) or from trophectoderm cells at the blastocyst stage 1, 5
Three Main Types of PGT
PGT-A (Aneuploidy screening): Screens embryos for chromosomal number abnormalities 2
PGT-M (Monogenic disorders): Detects single-gene disorders like cystic fibrosis, sickle cell disease, or BRCA1/2 mutations 1, 2
PGT-SR (Structural rearrangements): Identifies chromosomal structural abnormalities like translocations 3, 2
Medical Indications
The NCCN guidelines emphasize that PGT should be used for serious hereditary disorders with high penetrance, early onset, and significant morbidity/mortality 1, 6
- Couples at risk for transmitting hereditary diseases to offspring (e.g., BRCA1/2 pathogenic variants, Fanconi anemia) 1, 4
- Chromosomal translocations or structural rearrangements in parents 3, 5
- Recurrent pregnancy loss or repeated IVF failures related to chromosomal abnormalities 4, 7
- Advanced maternal age with increased aneuploidy risk 4, 5
Alternative Context: Primary Graft Dysfunction
In cardiac transplantation, PGD stands for Primary Graft Dysfunction, affecting approximately 7% or more of patients after cardiac transplantation and representing the leading cause of early mortality 1
- PGD of the right ventricle alone requires: RAP >15 mm Hg, PCWP <15 mm Hg, cardiac index <2.0 L·min⁻¹·m⁻², and either transpulmonary gradient <15 mm Hg with PASP <50 mm Hg or need for right ventricular assist device 1
- The pathogenesis involves donor factors, procedural factors, inflammatory mediators from brain death, elevated pulmonary vascular resistance, and ischemia/reperfusion injury 1
Common Pitfall
Context matters critically: In reproductive medicine/genetics, PGD refers to preimplantation genetic diagnosis 1, 2, while in cardiac transplantation, PGD means primary graft dysfunction 1. Always clarify the clinical context when encountering this abbreviation to avoid misinterpretation.