H. Karadayi

Short tandem repeats haplotyping of the HLA region in preimplantation HLA matching.

Recently, preimplantation genetic diagnosis (PGD) has been considered for several indications beyond its original purpose, not only to test embryos for genetic disease but also to select embryos for a nondisease trait, such as specific human leukocyte antigen (HLA) genotypes, related to immune compatibility with an existing affected child in need of a haematopoetic stem cell (HSC) transplant. We have optimized an indirect single-cell HLA typing protocol based on a multiplex fluorescent polymerase chain reaction (PCR) of short tandem repeat (STR) markers scattered throughout the HLA complex. The assay was clinically applied in 60 cycles from 45 couples. A conclusive HLA-matching diagnosis was achieved in 483/530 (91.1%) of the embryos tested. In total, 74 (15.3%) embryos revealed an HLA match with the affected siblings, 55 (11.4%) of which resulted unaffected and 46 (9.5%) have been transferred to the patients. Nine pregnancies were achieved, five healthy HLA-matched children have already been delivered and cord blood HSCs, were transplanted to three affected siblings, resulting in a successful haematopoietic reconstruction.

Clinical aspects of preimplantation genetic diagnosis for single gene disorders combined with HLA typing

Preimplantation genetic diagnosis (PGD) for single gene disorders combined with human leukocyte antigen (HLA) matching has recently emerged as a therapeutic tool for stem cell transplantation in couples bearing an affected offspring. There may exist, however, several patient- or cycle-specific limitations for certain couples. This article documents data regarding experience of single gene disorders combined with HLA matching obtained at Istanbul Memorial Hospital, Turkey. The data were obtained from 20 couples undergoing 26 PGD-HLA cycles for thalassaemia (n = 23), Wiscott-Aldrich syndrome (n = 1) and acute lymphoblastic leukaemia (n = 2). A total of 206 embryos was biopsied on day 3 of embryo development and subsequently analysed. After the analysis, 26 (12.6%) of them were found to be both healthy and HLA compatible. In 16 embryo transfers performed, seven (43.7%) clinical pregnancies were obtained, one of which resulted in miscarriage. Ten of the 26 cycles started (38.4%) were cancelled due to a lack of suitable (mutation-free and/or HLA-compatible) embryos. The data suggest that application of PGD in combination with HLA typing is a promising therapeutic tool for an affected sibling.

Medical and social perspectives of PGD for single gene disorders and human leukocyte antigen typing

Preimplantation genetic diagnosis (PGD) for single gene disorders combined with human leukocyte antigen (HLA) typing has recently emerged as a therapeutic tool. For couples who are at risk of passing on a genetic disease to their offspring, preimplantation embryos can be selected according to their genetic status as well as a possible HLA matching with the affected sibling. Stem cells from the resulting babys umbilical cord blood have, therefore, a great therapeutic value for haematopoietic and other life threatening diseases, as stem cells in the cord blood from a HLA-compatible newborn can be used for transplantation without graft rejection, thus saving an affected childs life. However, apart from being a valuable treatment option, there exist several medical and social aspects that should be evaluated and discussed. From the ethical and the social aspects, although PGD for single gene disorders is well defined and accepted, application of PGD combined with HLA typing is less obvious and under extensive debate. This article is aimed at summarizing the current results and limitations of PGD with HLA typing that are related to the successful medical outcome. It further discusses the ethical and social issues that have recently been raised on the application of this technique.

P-39 Preimplantation genetic diagnosis for epidermolysis bullosa

embryos were transferred to the patient and a singleton pregnancy was obtained. Our patient gave birth and we confirmed the healthy birth. Conclusion: These results show the feasibility of PGD for NM, NEB gene. This technique could be applicable to families suffering from NM disease NEB gene mutation carriers as well since they share similar mutation and clinical manifestations.