Mark Roesler

Birth of a healthy infant following preimplantation PKHD1 haplotyping for autosomal recessive polycystic kidney disease using multiple displacement amplification.

PurposeTo develop a reliable preimplantation genetic diagnosis protocol for couples who both carry a mutant PKHD1 gene wishing to conceive children unaffected with autosomal recessive polycystic kidney disease (ARPKD).MethodsDevelopment of a unique protocol for preimplantation genetic testing using whole genome amplification of single blastomeres by multiple displacement amplification (MDA), and haplotype analysis with novel short tandem repeat (STR) markers from the PKHD1 gene and flanking sequences, and a case report of successful utilization of the protocol followed by successful IVF resulting in the birth of an infant unaffected with ARPKD.ResultsWe have developed 20 polymorphic STR markers suitable for linkage analysis of ARPKD. These linked STR markers have enabled unambiguous identification of the PKHD1 haplotypes of embryos produced by at-risk couples.ConclusionsWe have developed a reliable protocol for preimplantation genetic diagnosis of ARPKD using single-cell MDA products for PKHD1 haplotyping.

Preimplantation HLA haplotyping using tri-, tetra-, and pentanucleotide short tandem repeats for HLA matching

PurposeTo aid couples wishing to conceive children who are HLA matched to a sibling in need of a hematopoietic progenitor cell transplant, we developed a preimplantation HLA haplotype analysis of embryos that utilizes tri-, tetra-, and pentanucleotide STR markers.MethodsFor preimplantation HLA genotyping, we use polymorphic STR markers located across the HLA and flanking regions, selecting exclusively tri-, tetra-, and pentanucleotide repeats. These markers can be resolved using either capillary electrophoresis (CE) or polyacrylamide gels.ResultsWe have developed 43 reliable STR markers for preimplantation HLA matching. Selected STR markers enabled unambiguous identification of embryos whose HLA haplotypes were matched with the affected patient using polyacrylamide gel or capillary electrophoresis.ConclusionsThe use of tri-, tetra-, and pentanucleotide repeat markers and polyacrylamide gels for STR genotyping in HLA matching is a simple and cost effective approach to clinical testing.

Karyotype analysis of blighted ova in pregnancies achieved by in vitro fertilization

Pregnancies achieved by IVF and resulting in blighted ovum were karyotyped. The rate of aneuploidy was found to be 38% (5/13). In vitro fertilization does not appear to be a risk factor for chromosome anomaly in live births or miscarriages, and the data reported so far may suggest that aneuploid rates are actually lower for pregnancies achieved by IVF.

Preimplantation Genetic Testing: Current Status and Future Prospects

While in vitro fertilization (IVF) is most often employed as a remedy for infertility, a discussion of the field would not be complete if it did not address the application of IVF to avoid genetic disorders. IVF makes it possible to assess the genetic status of the embryo before establishing a pregnancy when couples are at risk for an affected child. Physicians in the field will benefit from being informed about the diverse set of molecular and cytogenetic technologies employed in preimplantation genetic diagnosis (PGD) and screening (PGS), and from understanding their relative power and limitations as tools for genetic counseling.