STR-HLA配型試驗於胚胎著床前基因診斷(PGD)之運用

Abstract

Preimplantation HLA matching has recently emerged as a tool for couples desiring to conceive a potential donor progeny for transplantation in a sibling with a life-threatening disorder . DNA in single blastomeres removed from 8-cell embryos by embryo biopsy following in vitro fertilization (IVF) was analyzed for short tandem repeats (STR) in the HLA region to select and transfer only those embryos that were HLA matching to affected siblings . In this study , the allele frequency and the prevalence rate of seventeen short tandem repeats (STR) makers which are located in HLA complex region (6p21.3) in 100 Taiwan individuals were analyzed . The selected STR makers displayed high heterozygosity, broad distribution of alleles and identifiable allelic size ranges ; thus , obtained the accurate result for a single lymphocyte . The allele drop-out (ADO) remains a significant problem for single cell PCR and diagnosis of single-gene disorders . Biopsy is done by removing one blastomere from a cleavage-stage embryo having 6-8 cells , and can also be done at the blastocyte stage , involving the removal of multiple trophectoderm cells . In the second part of this study , we further evaluate the performance of the newly developed whole genome amplification (WGA) in DNA amplification and compared with the traditional Nested PCR strategy . The ADO rates of whole genome amplification (WGA) for a single lymphocyte and five lymphocytes were 34.0% and 20.9% , accordingly . The ADO rates of Nested PCR for a single lymphocyte and five lymphocytes were 45.4% and 27.2% , accordingly . Our data suggested that diagnostic accuracy for DNA analysis in minimal cell would be benefit significantly from the biopsy of larger number of cells (from one cell to 5 cells) and the performance could be further improved by using whole genome amplification (WGA) technique .