Preimplantation genetic diagnosis (pgd) is an option for carrier couples who want to assure their child’s health regarding genetic disorders before pregnancy. here we present application of molecular pgd to select healthy hla-matched embryos as a donor for bone marrow or stem cell transplantation of the affected sibling.
Methods
19 couples who had an affected child candidate for transplantation, referred to our laboratory. peripheral blood samples collected and genomic dna extracted using salting out method. mutation detection carried out using sanger sequencing. fragment analysis performed to trace defective alleles using multiplex short tandem repeats (strs). linkage analysis performed to illustrate hla haplotype. fertilization procedure carried out at in vitro fertilization (ivf) clinic. after three days one blastomere removed from each embryo. causative mutation and informative str markers associated with both disease and hla were checked for blastomeres using nested pcr. haplotype mapping performed and unaffected hla-matched embryos were selected and implanted to mother’s uterus.
Results
Since 2009 we have performed pgds combined with hla typing for 147 blastomeres. 74 of them were for beta-thalassemia carriers, 46 of them were for fanconi anaemia carriers, 19 of them were for epidermolysis bullosa carriers and 8 of them were for familial haemophagocytic lymphohistiocytosis 4 carriers.
Conclusion
Pgd combine with hla typing is a strategy to select unaffected hla-matched embryos as a donor when transplantation is the only choice. results obtained from linkage analysis and haplotype mapping in parallel with direct mutation detection make this method more accurate and reliable.
