Thursday, September 15, 2016

Prenatal and pre-implantation genetic diagnosis (Nature Reviews Genetics)

An IFV cycle can produce multiple (e.g., 5-10 for younger mothers) viable embryos. This leads to an inevitable Embryo Selection Problem. Genomic advances allow for better-informed selection, raising complex ethical issues.
Prenatal and pre-implantation genetic diagnosis

Nature Reviews Genetics 17, 643–656 (2016) doi:10.1038/nrg.2016.97
Published online 15 September 2016

The past decade has seen the development of technologies that have revolutionized prenatal genetic testing; that is, genetic testing from conception until birth. Genome-wide single-cell arrays and high-throughput sequencing analyses are dramatically increasing our ability to detect embryonic and fetal genetic lesions, and have substantially improved embryo selection for in vitro fertilization (IVF). Moreover, both invasive and non-invasive mutation scanning of the genome are helping to identify the genetic causes of prenatal developmental disorders. These advances are changing clinical practice and pose novel challenges for genetic counseling and prenatal care.
From the paper:
Whole-genome analysis of pre-implantation embryos provides information about not only the disorder tested for, but the whole genomic make-up of the embryo. This not only allows for improved selection, but also provides information on genetic variants that are associated with several non-health-related traits. These prospects raise difficult ethical questions. Some people may see this as the slippery slope towards the ‘designer child’ (REF. 136), whereas a different perspective is that it enables prospective parents and professionals to take into account the welfare of the future child. Following the principle of procreative beneficence, it is common practice to rank embryos and select the embryo with the highest chance of resulting in a healthy individual137. This raises questions as to whether prospective parents have the right to select for the best embryo and how to define ‘best’, especially in the context of genome-wide analysis.


With further technological improvements and increasing success rates, prenatal and pre-implantation diagnosis of genetic disorders will become commonplace, and with increasing public acceptance a continued growth in their implementation can be anticipated. This implementation, in turn, will reduce the frequency of rare severe inherited genetic diseases. Increasingly, more common genetic variants causing late-onset disorders (for example, BRCA1 and BRCA2) or recessive disorders (for example, cystic fibrosis) could also be selected against and will eventually become rare. In the future, new diagnostic technologies will not only provide a tool to give parents the option of an informed choice, but they will also lead towards fetal personalized medicine ...

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