First pregnancy and life after preimplantation genetic diagnosis by polar body analysis for mucopolysaccharidosis type I.

Preimplantation genetic diagnosis (PGD) may help couples at risk to avoid pregnancies with known genetic diseases. In Germany, the only option to perform PGD is the analysis of polar bodies (PB). Mucopolysaccharidosis type I (MPS I) is an autosomal recessive lysosomal storage disorder. Q70X is one of the frequent diseases causing mutations of alpha-L-iduronidase (IDUA), leading to a severe phenotype with mental retardation and various somatic abnormalities, and making a request for PGD is understandable. Using five polymorphic DNA markers from the vicinity of IDUA, PGD on first PB was performed for a consanguineous couple, both heterozygotes of the Q70X mutation of IDUA. Sixteen first PB were obtained by laser assisted hatching of the zona pellucida. Genotyping led to the conclusion that 3/16 oocytes carried wild-type IDUA alleles. Only one of these oocytes showed pronucleus formation after intracytoplasmic sperm injection and was transferred on day 2 after oocyte retrieval. A singleton pregnancy was established. Prenatal diagnosis showed a fetus heterozygous for Q70X. For MPS I, PB analysis is a feasible way to perform PGD and it may be an acceptable alternative for couples with moral objections to embryo selection, or for countries in which genetic testing of the embryo is prohibited.

Polar body diagnosis for hemophilia a using multiplex PCR for linked polymorphic markers.

Preimplantation genetic diagnosis (PGD) is usually performed on blastomeres. In Germany, the only possibility to perform PGD is by analysis of polar bodies. We performed PGD using polar bodies in a woman who is a carrier of hemophilia A. Multiplex PCR followed by nested fluorescent PCR for five linked polymorphic markers was established. From 11 analyzed polar bodies, only 1 showed alleles linked to the mutation. The corresponding oocyte was transferred and no pregnancy was established. As seen in other investigations, the rate of heterozygous first polar bodies is surprisingly high.