Preimplantation Genetic Testing for HLA-matching: An Overview of Clinical Application and Utility

Abstract

Preimplantation Genetic Testing for Human Leucocyte Antigen-matching (PGT-HLA), first reported in 2001, has been one of the most controversial PGT applications. The procedure aims to identify an embryo that is not only healthy but also HLA-matched with a sibling in the family in need of hematopoietic stem cell transplantation (HSCT), considering that sibling HSCT stands the highest chance of success in comparison to alternative approaches of donor selection. HLA-typing can be performed with or without PGT for the exclusion of a monogenic disorder (PGT-M). The diagnostic PGT approach has greatly evolved over the years. HLA haplotyping by linkage analysis has been the most commonly applied generic approach to date but nowadays newer techniques (SNP arrays, NGS) are also being applied. PGT-HLA is a complex procedure that must be very well orchestrated between specialists of many different disciplines to ensure that successful HSCT is completed in time for the maximum benefit of the recipient. This review discusses the procedure and methodology of PGT, clinical application, and utility of PGT-HLA, and underlines how, despite the limitations, it has been a successful and realistic approach for many couples.