Pre-implantation HLA matching: The production of a Saviour Child.

Pre-implantation genetic diagnosis (PGD) requires the use of assisted reproductive technology (ART) to create several pre-implantation-stage embryos, followed by biopsy of embryonic cells for genetic testing and transfer of selected embryos to the womb to establish a pregnancy. HLA typing of ART-created embryos was first reported in 2001. The aim is to establish a pregnancy that is HLA-compatible with an affected sibling who requires haematopoietic stem cell transplantation. HLA-typing can be performed with or without PGD for the exclusion of a single-gene disorder. Haematopoietic stem cells collected from the umbilical cord blood or the bone marrow of the HLA-matched donor sibling born, or a combination of both sources, are used for transplantation and cure of the affected sibling. The procedure is multistep and technically challenging. All specialists involved must aim to adequately support and counsel prospective parents. Results have so far been encouraging, with many documented positive outcomes of affected children being cured.