Review: preimplantation diagnosis of inherited disease

Growth and health outcome of 102 2-year-old children conceived after preimplantation genetic diagnosis or screening

OBJECTIVE

The major objective of this study was to determine whether the embryo biopsy procedure might cause growth restriction or affect health outcome of children.

STUDY DESIGN

Auxological data and physical findings were compared at birth and age 2 for 102 children (70 singletons and 32 twins) born after PGD/PGS and 102 matched children born after intracytoplasmic sperm injection (ICSI) in a prospective study.

RESULTS

No statistically significant differences regarding weight, height and head circumference standard deviation scores (SDS) at birth and at age two years were observed. At two years of age the mean BMI SDS tended to be lower in PGD/PGS children (p=0.058). PGD/PGS babies had been more often breastfed (p=0.013), but mostly during a shorter time. The prevalence of major as well as minor congenital anomalies, hospital admissions and surgical interventions was similar.

CONCLUSION

Children born after embryo biopsy applied in PGD/PGS present similar prenatal and postnatal growth and health outcome in the first two years of life compared to ICSI children. Up till now, PGD and PGS appear not to be associated with a higher risk for health problems.

Ethics and assisted reproduction

In vitro fertilization and assisted reproductive technology have made great progress during the last 20 years. Genetic material donation, human embryo cryopreservation, selective embryo reduction, preimplantation genetic diagnosis and surrogacy are currently practiced in many countries. On the other hand, embryo research is practiced only in a small number of nations, whereas human cloning has thus far been universally condemned. The rapid evolution and progress of all these techniques of assisted reproduction has revealed certain ethical issues that have to be addressed.

Multiplex PCR of polymorphic markers flanking the CFTR gene; a general approach for preimplantation genetic diagnosis of cystic fibrosis

Cystic fibrosis (CF) is the first monogenic disorder for which single cell preimplantation genetic diagnosis (PGD) has been successfully applied. The spectrum of mutations in CF is extremely heterogeneous, and hence, the development of mutation-specific PGD protocols is impracticable. The current study reports the development and evaluation of a general multiplex marker polymerase chain reaction (PCR) protocol for PGD of CF. Four closely linked highly polymorphic (CA)(n) repeat markers D7S523, D7S486, D7S480 and D7S490, flanking the cystic fibrosis transmembrane regulator (CFTR) gene, were used. In 99% of the single cells tested (100 leukocytes and 50 blastomeres), multiplex PCR results were obtained and the overall allelic drop out (ADO) rate varied from 2 to 5%. After validation for the presence of ADO and additional alleles, 95% of the multiplex PCR results were accepted to construct the marker genotypes. Depending on the genotype of the couple, and taking into account the embryos lost for transfer due to validation criteria (5%), ADO (0-2%) and single recombination (1.1-3%), in general >90% of the embryos could be reliably genotyped by PGD using a single blastomere. The risk of misdiagnosis equals the chance of a double recombination between informative flanking markers and is <0.05%. Therefore, this polymorphic and multi-allelic marker system is a reliable and generally applicable alternative for mutation-directed PGD protocols. Furthermore, it provides a test for the origin of the detected genotype and also gives an indication of the chromosomal ploidy status of the blastomere tested.

A historical perspective of the clinical evolution of the assisted reproductive technologies

The practice of assisted reproduction technology today is the result of the dedicated patient care, observation, research, and experimentation undertaken by previous generations of physicians. The building blocks of progress have been assembled over past decades, by scientists whose primary objective has been to push forward the frontiers of knowledge, in order to offer more effective methods of infertility treatment. And fortunately that process continues today. Amongst the many scientific developments that have led to the modern practice in assisted reproductive technology, a small number stand out as having had a unique importance. This historical review redraws the path through which in vitro fertilization went from an experimental to an accepted infertility treatment.

Triplet pregnancy with acardius acranius after preimplantation diagnosis

OBJECTIVE

To report the first case of fetal malformation after preimplantation diagnosis for Duchenne muscular dystrophy (DMD).

DESIGN

Case report.

SETTING

Perinatal center in a university hospital.

PATIENT(S)

A conductor for DMD in her third pregnancy.

INTERVENTION(S)

Preimplantation diagnosis was performed in an outside hospital. In our center, a dichorionic triplet pregnancy with acardius acranius was diagnosed. The anastomosis between the "pump"-twin and the fetus with acardius was embolized with histoacryl to prevent worsening cardiac insufficiency of the "pump"-twin.

MAIN OUTCOME MEASURE(S)

Pregnancy outcome.

RESULT(S)

The anastomosis between the "pump"-twin and the fetus with acardius was occluded successfully. Premature preterm rupture of membranes led to rapid labor and delivery at 24 + 5 weeks' gestation. The smaller girl died of severe hyaline membrane disease, whereas the other infant had no major clinical problems and has developed well.

CONCLUSION(S)

There might be an association between embryo biopsy and fetal malformations. The setting up of a birth register after embryo biopsy is strongly recommended.