Approaches to HLA-genotyping of human embryos in order to select donors for children with hematological and immunological disorders
Most hematological malignancies, primary immunodeficiencies and hematological-inherited disorders in children can be cured by hematopoietic stem cell transplantation (HSCT). In most cases an HLA-identical sibling is required. Preimplantation Genetic Diagnosis (PGD), has been introduced for couples at risk of transmitting genetic disorder to their offsprings to select unaffected embryos for transfer insuring a disease free pregnancy. PGD is performed by testing single blastomeres, removed from preimplantation embryos, obtained by In Vitro Fertilization. Recently preimplantation HLA typing has been proposed as a new application of PGD for creating a tissue matched child that can serve as a hematopoietic stem cell donor for a sick sibling in need of a stem cell transplant. This article describes the development, application and comparison of two approach­es to preimplantation HLA typing involving ASP-PCR and indirect STR-based HLA haplotyping. Indirect STR haplotyping has demonstrated an increased sensitivity (95.5%) and specificity (99%) and became a method of choice for extensive applica­tion in PGD. Developed rapid and non labour-intensive protocol for preimplantation STR-genotyping has been applied in 246 IVF/PGD cycles, resulting in birth of 45 healthy babies HLA matching to their affected siblings.